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Publication Date: 2026
Biomass and Bioenergy (09619534) 204
This study focuses on the simultaneous production of biobutanol and biodiesel, viable alternatives to gasoline and diesel used in urban settings, aiming to enhance valorization of municipal solid waste (MSW) as the feedstock. The process involves a multi-stage pretreatment including simultaneous extraction of inhibitors and lipids, dilute acid and crude glycerol pretreatment, and enzymatic hydrolysis followed by anaerobic fermentation using Clostridium acetobutylicum for biobutanol production. The use of crude glycerol, a biodiesel byproduct, as a green solvent in the pretreatment, reduces the need for traditional costly solvents. Optimal conditions were determined for the highest production of acetone, butanol, and ethanol (ABE) were lipid extraction and inhibitor removal by ethanol followed by 1 % w/w dilute acid pretreatment at 120 °C for 10 min. Under these conditions, fermentation of the pretreatment liquid yielded concentrations of 5.42 g/L acetone, 11.32 g/L butanol, and 1.35 g/L ethanol. Moreover, fermentation of the hydrolysate resulted in concentrations of 2.13 g/L acetone, 4.28 g/L butanol, and 0.78 g/L ethanol. Moreover, the optimal conditions for biodiesel production were determined as methanol-to-oil ratio of 9.14:1, temperature of 59.5 °C, catalyst percentage of 0.886 %, and reaction time of 67 min. Under these conditions, a high yield of biodiesel (96.91 %) was achieved from the extracted oil using ethanol:acetone ratio of 1:3. Overall, this integrated approach produced 137.2 g of ABE and 75.1 g of biodiesel per kg of MSW, demonstrating the potential of MSW as a sustainable feedstock for dual-grade biofuel production. © 2025 Elsevier Ltd
Publication Date: 2025
Industrial Crops and Products (09266690) 223
The laccase enzyme is considered as a highly effective catalyst with extensive applications in lignin degradation and sustainable energy production from lignocellulosic biomass. This study presents a novel approach for the degradation of phenolic compounds found in the structure of lignocellulosic biomasses by using laccase immobilized on the surface of nanocellulose-functionalized magnetic nanoparticles (Fe3O4@NC@Enz). The synthesis of this nanobiocatalyst was confirmed through various characterization techniques. Under optimal immobilization conditions, incubation time of 8 hours and enzyme concentration of 2 mg/mL, an impressive immobilization yield of 93.26 % and a relative activity of 90.32 % were achieved. The immobilized laccase demonstrated a storage stability of 68.9 % of its initial activity over a 60-day storage period and exhibited superior stability to that of the free enzyme under various pH and temperature conditions. This study investigated the application of Fe3O4@NC@Enz for degrading phenolic compounds, achieving a notable degradation rate of 84.74 % of the total polyphenol content in the lignin structure while retaining 72.4 % of its catalytic activity after 12 reuse cycles. The immobilized laccase was also effective in both delignification and detoxification of corncob, reaching rates of 72 % and 86.69 %, respectively, after 12 hours of incubation. In conclusion, the findings underscore the effectiveness of the Fe3O4@NC@Enz to improve enzyme stability, activity, and reusability, offering a promising approach for the efficient delignification and detoxification of lignocellulosic biomasses. © 2024 The Authors
Publication Date: 2025
Biofuels, Bioproducts and Biorefining (1932104X)
Efficient hydrolysis of hemicellulose to fermentable carbohydrates is crucial for producing butanol from lignocellulose. This study investigates hydrothermal pretreatment catalyzed by dilute trifluoroacetic acid (DTFA) to enhance the hydrolysis of hemicellulose in corncob. DTFA pretreatment generated a fermentable hemicellulose hydrolysate containing 75–80% xylan as xylose and a glucan-rich solid. Pretreatment at 150 °C with 0.05 M trifluoroacetic acid released 80% xylan, yielding 23 g L−1 xylose and 13.8 g L−1 other sugars. Enzymatic hydrolysis of the 65.5% glucan solid yielded a cellulosic hydrolysate with 26 g L−1 glucose. DTFA pretreatment improved hydrolysis efficiency by 243% over untreated corncob and 62% over dilute sulfuric acid pretreatment. Acetone–butanol–ethanol (ABE) fermentation of the hydrolysates by Clostridium acetobutylicum produced 7.8–7.9 g L−1 ABE, utilizing 97% glucan and 75% xylan. The process was assessed based on the concentration of inhibitors and fermentable sugars. Dilute trifluoroacetic acid pretreatment yields 187 g of ABE per kg of corncob, compared with 42 g for DSA. © 2025 Society of Industrial Chemistry and John Wiley & Sons Ltd.
Publication Date: 2025
Biomass and Bioenergy (09619534) 200
This study investigates a sequential process using triticale straw (TSW) as a substrate, integrating acetone-butanol-ethanol (ABE) fermentation with in-situ butanol extraction, followed by oleaginous fermentation of the residual medium containing volatile fatty acids (VFAs) to produce single-cell oil (SCO). Using XAD-4 Amberlite adsorbent for in-situ ABE separation, the residual broth was converted to SCO by Cryptococcus aureus. Pretreatment of the straw with either dilute acid (1 % H2SO4) or alkaline (1 % NaOH) was followed by enzymatic hydrolysis using Cellic® CTec2 enzymes, achieving a glucose yield of 85 % at the optimal condition (170 °C, 1 %NaOH). The untreated TSW showed a total sugar concentration of 4.12 g/L after 72 h, with production of 0.68 g/L butanol, 0.17 g/L ethanol, and 0.70 g/L SCO in the subsequent fermentation stage. Pretreatment significantly enhanced ABE production, with dilute acid pretreatment generating 28.0 g/L of total sugars and resulting in 9.0 g/L of solvents in the subsequent ABE fermentation. The highest ABE production (11.82 g/L) was obtained from the alkali-pretreated straw at 170 °C. XAD-4 Amberlite further increased ABE concentration to 12.97 g/L. Optimal biomass and lipid production (9.96 g/L and 3.25 g/L, respectively) were also attained following alkaline pretreatment. These results demonstrate the potential of triticale straw for sustainable butanol and lipid production. © 2025 Elsevier Ltd
Publication Date: 2025
Bioresource Technology (0960-8524) 419
Tannin-containing sorghum grains, suitable for acetone-butanol-ethanol (ABE) production by Clostridium acetobutylicum, have required pretreatment to eliminate tannins inhibiting the strain's amylolytic activity. This study investigates biobutanol production enhancement by immobilizing enzymes on polydopamine-functionalized polyethersulfone (PES) membranes with magnetic nanoparticles for Separated Hydrolysis and Fermentation (SHF) and Simultaneous Saccharification and Fermentation (SSF) processes. After multi-stage hot water treatment, TG3 sorghum (from the third stage) was used, where the enzyme-immobilized PES membrane produced 4.75 g/L of ABE (3.24 g/L butanol) under SSF, 0.85 g/L under SHF, and 1.1 g/L under simple fermentation. For TG6 (from the sixth stage), 3.23, 1.29, and 1.25 g/L of ABE was produced under SSF, SHF, and simple fermentation, respectively. This enhanced performance is due to the reduced enzyme inhibition. Reusability experiments showed that the membrane retained 30 % of initial activity after three cycles. These findings suggest that enzyme-immobilized membranes can intensify ABE production and enable integrated cell recovery. © 2025 Elsevier Ltd
Publication Date: 2025
Nature Food (26621355) 6(4)pp. 323-330
Food loss and waste (FLW) valorization remains challenging due to mixed properties and composition arising from seasonal and regional variations in food production. Here we examine the capacities of 3D printing for valorizing FLW streams, with a focus on FLW-based bioinks. We consider how waste management practices, 3D printing technology and emerging FLW valorization techniques could address challenges concerning raw material sourcing, improved material printability and suitable mechanical properties. Bioink ingredients incorporating biologically active compounds derived from FLW streams could offer tailored functionalities, supporting food preservation and economic, health and environmental sustainability benefits in line with the Sustainable Development Goals. © Springer Nature Limited 2025.
Publication Date: 2025
pp. 409-445
This chapter introduces life cycle assessment (LCA) as a critical tool for evaluating the environmental sustainability of lignin-driven materials. It begins by explaining the motivation behind sustainable product development, followed by a structured overview of LCA fundamentals, including its evolution, purpose, benefits, and standard methodologies. It explores the four ISO-standardized phases of LCA—goal and scope definition, life cycle inventory, life cycle impact assessment, and interpretation—using accessible language and practical illustrations. Special emphasis is given to the applicability of LCA in assessing lignin-derived materials, such as resins, fuels, and bio-based polymers, underscoring lignin’s role in replacing petrochemical feedstocks. A curated review of published LCA studies showcases methodological diversity and key findings across different lignin-based applications. To consolidate learning, a comprehensive case study guides readers through each LCA phase for a wood-based biorefinery that produces lignin as a coproduct. This hands-on section includes data collection, system modeling in SimaPro, and result interpretation, reinforcing conceptual understanding through practice. Overall, the chapter serves as both an introduction and a practical guide for using LCA in lignin-based sustainability research and innovation. © 2026 Elsevier Inc. All rights reserved.
Publication Date: 2025
Journal of Environmental Chemical Engineering (22133437) 13(3)
The trade-off between lignin incineration for energy and its valorization for biofuels and biochemicals is a central challenge in lignocellulosic biorefineries. This study introduces the lignin first-lignin modification (LF-LM) method - an enhanced version of the lignin-first (LF) method that improves lignin recovery and quality - offering a promising alternative to incineration and conventional LF strategies. To identify the most sustainable lignin utilization route, we performed a combined life cycle assessment (LCA) and techno-economic analysis (TEA) of four scenarios using sugarcane bagasse: (1) dilute acid (DA) pretreatment with lignin incineration (SC-base); (2) DA pretreatment with lignin pyrolysis (SC-1); (3) glycerol organosolv (GO) pretreatment with lignin pyrolysis (SC-2); and (4) PEG-assisted GO pretreatment with lignin pyrolysis (SC-3). The environmental impacts were evaluated using ReCiPe 2016 (H) in SimaPro, and the economic performance was assessed by calculating the ethanol minimum selling price (EMSP) via discounted cash flow analysis, supported by simulations in SuperPro Designer v9.0. Results show that SC-3 reduced total environmental damage by 36.66% and EMSP by 30.62% compared to SC-base, driven primarily by reductions in CO2 emissions and improvements in energy integration. Human health impacts accounted for over 90% of total environmental damage across all scenarios. Although SC-3 incurred higher capital costs, its environmental and economic advantages make it the most sustainable option. This study highlights the critical role of lignin valorization and process integration in improving the viability of second-generation ethanol production and underscores LF-LM as a superior strategy for sugarcane-based biorefineries. © 2025 Elsevier Ltd.
Publication Date: 2025
International Journal of Biological Macromolecules (01418130) 289
Microbial production of xanthan gum from forage sorghum straw (FSS) was investigated. The important aspect investigated was the synthesis of xanthan gum using hemicellulose as a substrate (hemicellulose-derived xanthan), a process that has been relatively underexplored in the existing literature. Xanthomonas campestris ATCC 33913 and an isolated strain from orange peel, identified as X. axonopodis, were utilized for xanthan production. The FSS hydrolysate obtained by treatment under 120 °C for 30 min and overliming, yielded xanthan gum concentration of 7.1 g/L for X. campestris and 6.9 g/L for X. axonopodis. The lower molecular weights of xanthan gum produced from FSS (590 kDa for X. campestris and 550 kDa for the isolated X. axonopodis), compared to those from glucose suggest distinct advantages for specialized applications. Xanthan gum from FSS also possessed a higher ratio of acetate to pyruvate, ranging from 1.5:1 to 1.91:1 for X. axonopodis and from 1.33:1 to 1.75:1 for X. campestris. This characteristic renders it an attractive choice for certain applications in the food industry. By utilizing this strain, 11.71 g of hemicellulose-derived xanthan gum and 13.8 g of cellulose-derived xanthan gum per 100 g of FSS were obtained, indicating a conversion rate of 25.51 %. © 2024 Elsevier B.V.
Publication Date: 2025
pp. 357-407
This chapter provides a comprehensive introduction to technoeconomic analysis (TEA) as applied to lignin-derived materials, emphasizing its role in evaluating the feasibility and economic viability of emerging biobased technologies. It systematically presents the TEA framework, covering process modeling, mass and energy balances, capital and operating cost estimation, and profitability metrics such as net present value, internal rate of return, minimum selling price, and payback period. Practical guidance is offered on simulation tools, including Aspen Plus and SuperPro Designer, along with methodologies for uncertainty and sensitivity analysis. Special attention is given to technology readiness levels, scale-up considerations, and commercial analysis—highlighting the importance of aligning technical development with market dynamics and investment criteria. Through detailed explanations and real-world case studies the chapter illustrates how TEA supports decision-making across the research, development, and deployment spectrum. Ultimately, it establishes TEA as a critical tool for guiding lignin valorization toward commercially competitive and environmentally sustainable outcomes. © 2026 Elsevier Inc. All rights reserved.
Publication Date: 2024
Renewable and Sustainable Energy Reviews (1364-0321) 189
The utilization of renewable fuel alternatives holds promise for reducing the financial burden of regulatory compliance and the social responsibility associated with greenhouse gas emissions. Hydrothermal liquefaction (HTL) is one of the most versatile technologies for converting renewable biomass feedstocks (especially in the wet state) into biofuel (biocrude oil) in a compact plant. Therefore, this review is devoted to thoroughly reviewing and critically discussing biocrude oil production from biomass feedstocks through the HTL process. This review starts by discussing the principles of biomass HTL processing and product upgrading, aiming to provide a grounded and broad understanding of current developments in this domain. The data reported in the published literature are analyzed and visualized in order to scrutinize the effects of the main process parameters on the quantity, quality, cost, and environmental impacts of resultant biofuels. Higher biocrude oil yields are obtained at temperatures, pressures, and residual times between 300 and 350 °C, 24–27 MPa, and 15–25 min, respectively. Concerning yield and calorific value, biocrude oil derived from homogeneous catalysts demonstrates figures of 23.6 % and 32.1 MJ/kg, whereas that from heterogeneous catalysts exhibits percentages of 66.8 % and 40 MJ/kg, respectively. The challenges and prospects for the future development of biocrude oil are also discussed. HTL has a long way to go before being used for biofuel production on a large scale. Future studies appear to be directed towards the use of HTL technology under the biorefinery framework to maximize the exploitation of biomass into value-added products, while minimizing waste generation. © 2023 Elsevier Ltd
Publication Date: 2024
Process Safety and Environmental Protection (17443598) 190pp. 1440-1449
The utilization of biogas as a renewable energy source necessitates a reduction in its CO2 content. “Ex-situ biomethanation” is employed to convert CO2 in biogas to CH4 through hydrogenotrophic methanogens. In this study, a biogas stream (32–36 % CO2) originating from cow manure digestion was subjected to treatment in a trickle bed bioreactor (4 liters). The presence of microorganisms on the packing material was confirmed by using a 16 S rRNA test and SEM images. This study stands out by considering all four combinations of thermophilic and mesophilic conditions, monitoring the transition and steady-state phases in a two-reactor series setup. The mesophilic-thermophilic mode yielded the highest purity (92 %) with an 86 % CO2 conversion rate and an energy density of 13,870 kJ/m3. Additionally, the performance consistency was also assessed using a larger TBB (8 liters). Extending the residence time, the thermophilic-thermophilic mode yielded the highest CH4 concentration at 98 %. The 16 S rRNA results revealed that, influenced by the designated growth conditions encompassing culture media, pH, temperature, and reactor retention time, an enrichment of hydrogenotrophic methanogens occurred. Furthermore, promising results in terms of CH4 concentration and process efficiency were demonstrated by the trickled bed bioreactor employing liquid-in-gas dispersion. © 2024 The Institution of Chemical Engineers
Publication Date: 2024
Process Safety and Environmental Protection (17443598) 187pp. 398-407
Bio-hydrogen (bio-H2) production from dark co-fermentation of pruning wastes, from pine, cypress, and berry trees, and food-rich municipal solid waste (FMSW) was evaluated as a promising way to combine waste management and renewable energy production. The inoculum was initially optimized by heat-shock pretreatment at 65, 75, 85, and 95 ℃ for 15, 30, and 45 min to maximize bio-H2 yields. The optimum pretreatment conditions (75 °C for 45 min) were applied for dark co-fermentation analyses. The highest bio-H2 production yield of 84 ± 6 mL/g VS was obtained by dark co-fermentation of 20 g/L pruning wastes and FMSW under initially neutral conditions. The fermentation of individual substrates led to 40.9, 0.2, 0.1, and 0.2 mL/g VS from FMSW, pine, berry, and cypress, respectively, 85% lower than that obtained through dark co-fermentation. Therefore, co-processing of a “stiff substrate”, lignocellulose, with a “loose part”, starchy FMSW, leads to a higher bio-H2 yield. Dark co-fermentation led to the bio-conversion of more than 76% of starch, 31% of glucan, and 41% of hemicellulose, besides 41% lignin removal. The modified Gompertz model (MGM) and Logistic model (MLM) were well-fitted on kinetic data (with R2 values ≥0.98), and the kinetic parameters were calculated. © 2024
Publication Date: 2024
Biomass and Bioenergy (09619534) 186
Synergy in the co-processing of lignocellulosic wastes and municipal biowaste (MB) can unlock their potential for biobutanol production. This study assessed the potential for biobutanol production through the co-processing of lignocellulosic waste and MB. Specifically, it compared the co-processing of paper waste with MB to that of garden waste and MB. Ethanol organosolv pretreatment served as a dual-function process for both pretreatment and detoxification purposes. Initial fermentation of hydrolysates from untreated paper waste using Clostridium acetobutylicum produced 0.9 g/L of acetone and ethanol but no detectable butanol. Organosolv pretreatment led to a significant increase in acetone and ethanol production but did not yield butanol. Co-processing paper waste with MB using organosolv pretreatment resulted in the production of 2.8–3.2 g/L butanol, along with increased acetone and ethanol production. Furthermore, co-processing a 1:1 (w/w) mixture of paper waste and MB under mild and severe pretreatment conditions produced 45.5 g and 43.4 g butanol, respectively, compared to 34.8 g and 14.4 g butanol when processing these waste streams separately. The study also explored the positive impact of co-processing garden waste with MB, a distinct lignocellulosic source, enhancing acetone-butanol-ethanol (ABE) yield by 27–40%. These findings highlight the potential of synergistic waste co-processing for achieving a more suitable balance of nutrients to enhance biobutanol and ABE production from biowastes. Additionally, the simultaneous treatment of lignocellulosic waste and municipal biowaste offers a simplified approach to waste processing, contributing to advancements in sustainable biomass utilization and bioenergy production. © 2024 Elsevier Ltd
Publication Date: 2024
Food Packaging and Shelf Life (2214-2894) 43
Food fraud is a pressing global challenge with far-reaching implications, necessitating robust preventive measures. The safeguarding of consumers from hazardous products, the preservation of supply chain integrity, and the assurance of fair competition all rely on effective anti-fraud strategies. Intelligent packaging technologies are pivotal in reducing food fraud through anti-tampering measures and traceability. However, standalone intelligent packaging technologies cannot alone establish comprehensive traceability within the food chain. This review asserts that integrating blockchain and artificial intelligence (AI) technologies can bolster traceability and combat food fraud. Blockchain enhances transparency, while AI enables precise analysis of extensive datasets. This comprehensive review critically examines the potential of combining blockchain and AI technologies with intelligent packaging to address food fraud. It thoroughly delineates the strengths and limitations of these technologies in detecting and mitigating fraud across the supply chain. The amalgamation of diverse technologies within intelligent packaging presents a holistic approach to mitigating significant fraud, contingent upon the effective resolution of technical, cost, and safety challenges. In conclusion, integrating sophisticated technologies into intelligent packaging offers a promising avenue to effectively combat food fraud, instill consumer trust, and maintain the integrity of the food supply chain. © 2024 Elsevier Ltd
Publication Date: 2024
Biomass and Bioenergy (09619534) 191
Construction of a green, economical, and energy-efficient lignocellulose pretreatment process is the core to improve the economic feasibility of the second-generation bioethanol production. This study presents an effective strategy for bioethanol production based on microwave-assisted Diisopropylammonium hydrosulfate ([DIP][HSO4]) pretreatment. The mechanisms for the depolymerization of the lignocellulose matrix in the novel pretreatment process were proposed by characterize the fractionated pulp and lignin. In this process, the effect of microwave power on mono-sugars production was also investigated. Results indicated that substantial removal of hemicellulose and lignin by 63.75 wt% and 59.36 wt %, respectively, were realized at 170 W for 3 min, which afforded to 69.69 % and 73.78 % of glucan and xylan recoveries in subsequent saccharification. Ethanol fermentation performances of the enzymatic hydrolysate of the pretreated pulps were evaluated using a C5/C6 co-assimilation Saccharomyces cerevisiae YL23. 34.35 g L−1 of ethanol with a yield of 0.42 g g−1 (total monomer sugars in hydrolysate) was received in the end fermentation broth using the fed-batch hydrolysate containing total 80.88 g L−1 of mono-sugars. Correspondingly, 12.01 g of bioethanol and 13.12 g of technical lignin were co-generated from 100 g of dried corn stover. © 2024
Publication Date: 2024
Fuel (0016-2361) 364
A multi-stage approach was evaluated for biohydrogen production from organic fraction of municipal solid waste and pruning, including pine, cypress, and mulberry wastes. The process consists of three stages: “starchy dark fermentation”, “intermediary autogenous acidic pretreatment”, and “lignocellulosic dark fermentation”. These stages synergistically contribute to the efficient conversion of organic waste into biohydrogen, offering an innovative solution for waste management while promoting sustainable energy production. In the first stage, easily degradable materials (starch) were utilized and converted into biohydrogen, underscoring the necessity of preventing their loss during the subsequent pretreatment stage. In the first stage, 72–78 % of starch was consumed, yielded 494–2,274 mL biohydrogen per 100 g waste. The second stage involved improving the structure of lignocellulose-rich solids through the application of volatile fatty acid-rich liquor generated in the first stage for pretreatment. In the second stage, the substrate was subjected to 120–180 °C for 60 min to pretreat the lignocelluloses catalyzed by the volatile fatty acids generated in the first stage. The third stage produced 119–3,154 mL biohydrogen from 100 g waste. At optimum conditions, the three-stage process yielded an overall of 5,228 mL hydrogen from 100 g of untreated substrate, 2.4-fold higher than one-stage dark fermentation. © 2024 Elsevier Ltd
Publication Date: 2024
Biofuels, Bioproducts and Biorefining (1932104X) 18(5)pp. 1554-1564
The production of value-added products from sewage sludge is considered to be one of the solutions for the sustainable management of sludge in wastewater treatment plants (WWTPs). The presence of carbon, nitrogen, and phosphorus sources has made the sewage sludge of WWTPs a valuable and low-cost substrate for the production of fermentative products. In the current study, a process was developed for microbial lipid production from two types of sewage sludge from a WWTP in northern Isfahan: anaerobic digester inlet sludge (DIS) and anaerobic digester outlet sludge (DOS). This process was based on the release of volatile fatty acids (VFAs) from the sludge by combinations of γ-ray irradiation, anaerobic digestion, and acidogenic fermentation followed by utilization of VFAs in a microbial process by the oleaginous yeast Cryptococcus aureus UIMC65. After γ-ray irradiation, the acidogenic fermentation of the treated sludge released 72% of the organic matter content of the sludge with acidification efficiency of 12% leading to 0.516 g L−1 VFAs. The oleaginous fermentation of the released VFAs for 7 days was accompanied by production of 1.58 g L−1 dry cell biomass with 40% lipid content. The results of this study indicate that the sewage sludge from urban WWTP has the potential to be used for the production of microbial lipids. © 2024 Society of Industrial Chemistry and John Wiley & Sons Ltd.
Publication Date: 2023
International Journal of Biological Macromolecules (01418130) 236
Large amounts of agricultural waste, especially marine product waste, are produced annually. These wastes can be used to produce compounds with high-added value. Chitosan is one such valuable product that can be obtained from crustacean wastes. Various biological activities of chitosan and its derivatives, especially antimicrobial, antioxidant, and anticancer properties, have been confirmed by many studies. The unique characteristics of chitosan, especially chitosan nanocarriers, have led to the expansion of using chitosan in various sectors, especially in biomedical sciences and food industries. On the other hand, essential oils, known as volatile and aromatic compounds of plants, have attracted the attention of researchers in recent years. Like chitosan, essential oils have various biological activities, including antimicrobial, antioxidant, and anticancer. In recent years, one of the ways to improve the biological properties of chitosan is to use essential oils encapsulated in chitosan nanocarriers. Among the various biological activities of chitosan nanocarriers containing essential oils, most studies conducted in recent years have been in the field of antimicrobial activity. It was documented that the antimicrobial activity was increased by reducing the size of chitosan particles in the nanoscale. In addition, the antimicrobial activity was intensified when essential oils were in the structure of chitosan nanoparticles. Essential oils can increase the antimicrobial activity of chitosan nanoparticles with synergistic effects. Using essential oils in the structure of chitosan nanocarriers can also improve the other biological properties (antioxidant and anticancer activities) of chitosan and increase the application fields of chitosan. Of course, using essential oils in chitosan nanocarriers for commercial use requires more studies, including stability during storage and effectiveness in real environments. This review aims to overview recent studies on the biological effects of essential oils encapsulated in chitosan nanocarriers, with notes on their biological mechanisms. © 2023 Elsevier B.V.
Publication Date: 2023
International Journal of Biological Macromolecules (01418130) 242
Depending on its physicochemical properties and antibacterial activities, chitosan can have a wide range of applications in food, pharmaceutical, medicine, cosmetics, agriculture, and aquaculture. In this experimental study, chitosan was extracted from shrimp waste through conventional extraction, microwave-assisted extraction, and conventional extraction under microwave process conditions. The effects of the heating source on the physicochemical properties and antibacterial activity were investigated. The results showed that the heating process parameters affected the physicochemical properties considerably. The conventional procedure yielded high molecular weight chitosan with a 12.7 % yield, while the microwave extraction procedure yielded a porous medium molecular weight chitosan at 11.8 %. The conventional extraction under microwave process conditions led to medium molecular weight chitosan with the lowest yield (10.8 %) and crystallinity index (79 %). Antibacterial assessment findings revealed that the chitosan extracted using the conventional method had the best antibacterial activity in the agar disk diffusion assay against Listeria monocytogenes (9.48 mm), Escherichia coli. (8.79 mm), and Salmonella Typhimurium (8.57 mm). While the chitosan obtained by microwave-assisted extraction possessed the highest activity against E. coli. (8.37 mm), and Staphylococcus aureus (8.05 mm), with comparable antibacterial activity against S. Typhimurium (7.34 mm) and L. monocytogenes (6.52 mm). Moreover, the minimal inhibitory concentration and minimal bactericidal concentration assays demonstrated that among the chitosan samples investigated, the conventionally-extracted chitosan, followed by the chitosan extracted by microwave, had the best antibacterial activity against the target bacteria. © 2023
Publication Date: 2023
Biotechnology Advances (0734-9750) 66
Chitin, as the main component of the exoskeleton of Arthropoda, is a highly available natural polymer that can be processed into various value-added products. Its most important derivative, i.e., chitosan, comprising β-1,4-linked 2-amino-2-deoxy-β-d-glucose (deacetylated d-glucosamine) and N-acetyl-d-glucosamine units, can be prepared via alkaline deacetylation process. Chitosan has been used as a biodegradable, biocompatible, non-antigenic, and nontoxic polymer in some in-vitro applications, but the recently found potentials of chitosan for in-vivo applications based on its biological activities, especially antimicrobial, antioxidant, and anticancer activities, have upgraded the chitosan roles in biomaterials. Chitosan approval, generally recognized as a safe compound by the United States Food and Drug Administration, has attracted much attention toward its possible applications in diverse fields, especially biomedicine and agriculture. Despite some favorable characteristics, the chitosan's structure should be customized for advanced applications, especially due to its drawbacks, such as low drug-load capacity, low solubility, high viscosity, lack of elastic properties, and pH sensitivity. In this context, derivatization with relatively inexpensive and highly available mono- and di-saccharides to soluble branched chitosan has been considered a "game changer". This review critically scrutinizes the emerging technologies based on the synthesis and application of lactose- and galactose-modified chitosan as two important chitosan derivatives. Some characteristics of chitosan derivatives and biological activities have been detailed first to understand the value of these natural polymers. Second, the saccharide modification of chitosan has been discussed briefly. Finally, the applications of lactose- and galactose-modified chitosan have been scrutinized and compared to native chitosan to provide an insight into the current state-of-the research for stimulating new ideas with the potential of filling research gaps. © 2023 Elsevier Inc.
Publication Date: 2023
pp. 1-333
Higher Alcohols Production Platforms: From Strain Development to Process Design comprehensively covers the production of higher alcohols, from the fundamentals to the latest research. Bringing together experts from industry and academia, the book sheds light on the practical aspects of higher alcohol production and offers a roadmap for researchers to follow. In addition to the fundamentals of higher alcohol production, readers are presented with detailed information on up and downstream processes, including microbial processes and the various production pathways available. A discussion of metabolic pathways has a dedicated chapter, as do C2, C3-C8, and C4 sugar fermentation platforms. A lifecycle assessment is also presented, addressing the energy, environmental, social and economic factors in the sustainability of higher alcohol production. Readers will find this to be a unique and comprehensive reference on the production of higher alcohols that will be of interest to students, researchers and industry professionals involved in bioenergy and renewable energy, and more. © 2024 Elsevier Inc. All rights reserved.
Publication Date: 2023
pp. 1-17
Alcohols have high potential as fuels, solvents, and building blocks for the production of a wide range of chemicals. To become a proper fuel, candidates should pass several assessments based on the physical properties such as density and viscosity and chemical properties such as combustion energy. The primary aliphatic alcohols between C3 and C7, the so-called higher alcohols, have recently attracted interest owing to their possible production from renewable carbohydrate resources through microbial pathways. In this chapter, different features of the higher alcohols are discussed to assess their potential as liquid fuels, reagents in synthetic chemistry, or solvents in industry. The considerable potentials of higher alcohols justify the enormous research efforts on developing synthetic pathways for their efficient microbial synthesis. © 2024 Elsevier Inc. All rights reserved.
Publication Date: 2023
pp. 271-303
One of the most current discussions in the transportation sector is air pollution caused by diesel engines. In fact, even with the advances in engine technologies, the combustion of diesel in internal combustion engines leads to the significant release of toxic gases into the atmosphere, such as particulate matter and nitrogen oxide, posing threats to human health and the environment. Although researchers proposed replacing petroleum-based diesel with bio-based diesel, technical, environmental, and economic challenges make their sustainability questionable. In line with that, more sustainable techniques have been introduced to reduce the toxic gas emissions from diesel combustion. Modifying diesel properties using fuel additives or reformulation is a straightforward and economical alternative among these techniques. Various additives, such as oxygenated, cetane number improvers, metal-based compounds, antioxidants, lubricity improvers, and cold flow improvers, are commercially used to improve diesel properties. Among these, higher alcohols as oxygenated additives due to their higher oxygen content and latent heat than diesel can shift the combustion process toward lower temperatures, lowering particulate matter and nitrogen oxide emissions. Despite the promising results offered by higher alcohols as fuel additives for diesel, the sustainability of their production from an environmental, economic, and social point of view should not be neglected. In better words, the decision-making process should not focus on the effects of higher alcohols on exhaust pollutants only, but also it should consider the principles of sustainable development in the background process of higher alcohols, that is, a cradle-to-grave approach. Life cycle sustainability assessment is a valuable tool to address this problem through systematical evaluation of environmental, economic, and social background processes or production of higher alcohols. This chapter aims to better understand the environmental, economic, and social aspects of higher alcohol production based on a life cycle sustainability assessment approach. © 2024 Elsevier Inc. All rights reserved.
Publication Date: 2023
International Journal of Biological Macromolecules (01418130) 239
Chitosan is one of the valuable products obtained from crustacean waste. The unique characteristics of chitosan (antimicrobial, antioxidant, anticancer, and anti-inflammatory) have increased its application in various sectors. Besides unique biological properties, chitosan or chitosan-based compounds can stabilize emulsions. Nevertheless, studies have shown that chitosan cannot be used as an efficient stabilizer because of its high hydrophilicity. Hence, this review aims to provide an overview of recent studies dealing with improving the emulsifying properties of chitosan. In general, two different approaches have been reported to improve the emulsifying properties of chitosan. The first approach tries to improve the stabilization property of chitosan by modifying its structure. The second one uses compounds such as polysaccharides, proteins, surfactants, essential oils, and polyphenols with more wettability and emulsifying properties than chitosan's particles in combination with chitosan to create complex particles. The tendency to use chitosan-based particles to stabilize Pickering emulsions has recently increased. For this reason, more studies have been conducted in recent years to improve the stabilizing properties of chitosan-based particles, especially using the electrostatic interaction method. In the electrostatic interaction method, numerous research has been conducted on using proteins and polysaccharides to increase the stabilizing property of chitosan. © 2023
Publication Date: 2023
pp. 99-123
Ethanol has the largest-volume production among the biotechnological products. Worldwide production of ethanol has increased almost three times during the last 15 years. Even though the technology for industrial ethanol production is quite mature, efforts have been made in order to enhance the production yield and productivity as well as decrease the production costs. The knowledge of commercial-scale cultivation and utilization of yeasts for ethanol production as well as the advances achieved in strain and process development can shed light on the way of higher alcohol development. In this chapter, the technologies for enhanced ethanol production, for example, process design challenges and engineering microorganisms, are discussed. © 2024 Elsevier Inc. All rights reserved.
Publication Date: 2023
pp. 125-156
By the start of the 21st century, biobutanol attracted interests as a drop-in liquid fuel that can be produced from renewable carbohydrate resources. A wide range of research studies dedicated to reviving the old acetone-butanol-ethanol (ABE) fermentation. ABE fermentation has been widely utilized all over the world at commercial scale during World War I and World Ward II for its acetone production but lost its economic vitality in the competition with petrochemical industry. In the search for a sustainable route from renewable resources to liquid biofuels, ABE fermentation attracted interests for n-butanol production. With such a unique industrial background, ABE fermentation has been targeted by some companies to be revived as an industrial process. Furthermore, the development of recombinant stains for the production of isobutanol had promising results and commercialized by two American companies. In this chapter, different aspects of microbial production of n-butanol and isobutanol are presented. © 2024 Elsevier Inc. All rights reserved.
Publication Date: 2023
Trends in Biotechnology (0167-7799) 41(6)pp. 785-797
Chitosan, an amino polysaccharide mostly derived from crustaceans, has been recently highlighted for its biological activities that depend on its molecular weight (MW), degree of deacetylation (DD), and acetylation pattern (AP). More importantly, for some advanced biomaterials, the homogeneity of the chitosan structure is an important factor in determining its biological activity. Here we review emerging enzymes and cell factories, respectively, for in vitro and in vivo preparation of chitosan oligosaccharides (COSs), focusing on advances in the analysis of the AP and structural modification of chitosan to tune its functions. By ‘mapping’ current knowledge on chitosan's in vitro and in vivo activity with its MW and AP, this work could pave the way for future studies in the field. © 2022 Elsevier Ltd
Publication Date: 2022
Nature Food (26621355) 3(10)pp. 822-828
Crustacean waste, consisting of shells and other inedible fractions, represents an underutilized source of chitin. Here, we explore developments in the field of crustacean-waste-derived chitin and chitosan extraction and utilization, evaluating emerging food systems and biotechnological applications associated with this globally abundant waste stream. We consider how improving the efficiency and selectivity of chitin separation from wastes, redesigning its chemical structure to improve biotechnology-derived chitosan, converting it into value-added chemicals, and developing new applications for chitin (such as the fabrication of advanced nanomaterials used in fully biobased electric devices) can contribute towards the United Nations Sustainable Development Goals. Finally, we consider how gaps in the research could be filled and future opportunities could be developed to make optimal use of this important waste stream for food systems and beyond. © 2022, Crown.
Publication Date: 2022
Renewable and Sustainable Energy Reviews (1364-0321) 156
The growing volume of municipal solid waste (MSW) generated worldwide often undergoes open dumping, landfilling, or uncontrolled burning, releasing massive pollutants and pathogens into the soil, water, and air. On the other hand, MSW can be used as a valuable feedstock in biological and thermochemical conversion processes to produce bioenergy carriers, biofuels, and biochemicals in line with the United Nations’ Sustainable Development Goals (SDGs). Valorizing MSW using advanced technologies is highly energy-intensive and chemical-consuming. Therefore, robust and holistic sustainability assessment tools should be considered in the design, construction, and operation phases of MSW treatment technologies. Exergy-based methods are promising tools for achieving SDGs due to their capability to locate, quantify, and comprehend the thermodynamic inefficiencies, cost losses, and environmental impacts of waste treatment systems. Therefore, the present review paper aims to comprehensively summarize and critically discuss the use of exergetic indicators for the sustainability assessment of MSW treatment systems. Generally, consolidating thermochemical processes (mainly incineration and gasification) with material recycling methods (plastic waste recovery), heat and power plants (steam turbine cycle and organic Rankine cycle), modern power technologies (fuel cells), and carbon capture and sequestration processes could improve the exergetic performance of MSW treatment systems. Typically, the overall exergy efficiency values of integrated MSW treatment systems based on the incineration and gasification processes were found to be in the ranges of 17–40% and 22–56%, respectively. The syngas production through the plasma gasification process could be a highly favorable waste disposal technique due to its low residues and rapid conversion rate; however, it suffers from relatively low exergy efficiency resulting from its high torch power consumption. The overall exergy efficiency values of integrated anaerobic digestion-based MSW processing systems (34–73%) were generally higher than those based on the thermochemical processes. Exergy destruction and exergy efficiency were the most popular exergetic indicators used for decision-making in most published works. However, exergoeconomic and exergoenvironmental indices have rarely been used in the published literature to make decisions on the sustainability of waste treatment pathways. Future studies need to focus on developing and realizing integrated waste biorefinery systems using advanced exergy, exergoeconomic, and exergoenvironmental methods. © 2021 Elsevier Ltd
Publication Date: 2022
Journal of Health System Research (27834093) 18(1)pp. 46-53
Background: The potato plant tuber is typically used at a rate of half million tons per year. However, its significant biomass in the form of leaf and stem of the plant is mainly unused. Different components of potato plant contain relatively high amount of toxic glycoalkaloids which limit the use of this biomass for various usages such as animal feed. These lignocellulosic wastes, 1 to 4 times the edible glands of the plant, can be utilized for production of biological butanol as an advanced biofuel, along with acetone and ethanol. Methods: In this study, extraction of acetone, ethanol, and methanol was used for reduction of glycoalkaloid content of biomass. The grinded leaves and stems were subjected to extraction of glycoalkaloids by solvent using Soxhlet, and then, before and after extraction of glycoalkaloids, were subjected to fermentation by Clostridium acetobutylicum. In addition, prior to fermentation, two stages of inhibitor removal and dilute acid pretreatment (1 wt%) at 180 ºC were performed for 1 hour to improve the yield of biological acetone, butanol, and ethanol (ABE) production. Findings: Leave and stem biomass of potato plant contained 74 and 48 mg/g glycoalkaloids, respectively. Butanol production was completely stopped in presence of higher than 0.07 mg/l glycoalkaloid in the fermentation media. After removing the inhibitors by solvents, fermentation led to the production of 3.2 and 3.8 g/l biological ABE from leaves and stems of potato plant, respectively. The amount of ABE production from leaves and stems after inhibitor removal increased by a factor of 4.7 and 2.4, respectively. Use of two consecutive stages of inhibitor removal and dilute acid pretreatment led to 14-and 4.7-fold higher ABE production from leaves and stems, respectively. Conclusion: Low glycoalkaloid content as a toxic substance can lead to complete disruption of the fermentation process. In addition, this substance can be removed using solvents and this renewable source can be used as one of the highly-produced wastes in the agricultural sector and as an important and inexpensive raw material for biofuel production. © 2022, Isfahan University of Medical Sciences(IUMS). All rights reserved.
Publication Date: 2022
International Journal of Biological Macromolecules (01418130) 207pp. 324-332
The recently developed technologies for immobilization of cellulase may address the challenges in costly hydrolysis of cellulose for cellulosic butanol production. In this study, a “hybrid” hydrolysis was developed based on chemical hydrolysis of cellulose to its oligomers followed by enzymatic post-hydrolysis of the resulting “soluble oligomers” by cellulase immobilized on chitosan-coated Fe3O4 nanoparticles. This hybrid hydrolysis stage was utilized in the process of biobutanol production from a waste textile, jeans waste, leading to selective formation of glucose and high yield of butanol production by Clostridium acetobutylicum. After validating the immobilization process, the optimum immobilization parameters including enzyme concentration and time were achieved on 8 h and 15.0 mg/mL, respectively. The reusability of immobilized enzyme showed that immobilized cellulase could retain 51.5% of its initial activity after three times reuses. Dilute acid hydrolysis of regenerated cellulose at 120–180 °C for 60 min 0.5–1.0% phosphoric acid led to less than 10 g/L glucose production, and enzymatic post-hydrolysis of the oligomers resulted in up to 51.5 g/L glucose. Fermentation of the hydrolysate was accompanied by 5.3 g/L acetone-butanol-ethanol (ABE) production. The simultaneous co-saccharification and fermentation (SCSF) of soluble and insoluble oligomers of cellulose led to 17.4 g/L ABE production. © 2022
Publication Date: 2022
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 435-453
Ethanol, as a neat chemical or gasoline blend, is the most consumed liquid biofuel for transportation purposes. At present, ethanol is industrially produced from sugar- and starch-based substrates, and ethanol production from lignocelluloses and algae is envisaged over the future. An industrial ethanol-producing microorganism, Saccharomyces cerevisiae, is well-known for ethanol production. However, some Zygomycetes and Ascomycetes species have emerged as ethanol producers. The advantages of using these fungi are high ethanol yield, titer and productivity, high tolerance to inhibitory chemicals in the fermentation broth, and having valuable fungal biomass as a by-product of fermentation. In addition, filamentous fungi may facilitate the production of n-butanol, as an advanced biofuel, from waste materials through different approaches. In this chapter, the production of ethanol by filamentous fungi and the potential roles of fungi in n-butanol production are discussed. © 2023 Elsevier Inc. All rights reserved.
Publication Date: 2022
Renewable and Sustainable Energy Reviews (1364-0321) 167
Liquid transportation biofuel production is a promising strategy to reduce greenhouse gas emissions. Hydrothermal gasification (HTG) has shown great potential as an effective method for valorizing wet biomass. The high-quality syngas produced using the HTG process can be chemically/biochemically converted to liquid biofuels. Therefore, this paper aims to comprehensively review and critically discuss syngas production from biomass using the HTG process and its conversion into liquid biofuels. The basics and mechanisms of biomass HTG processing are first detailed to provide a comprehensive and deep understanding of the process. Second, the effects of the main operating parameters on the performance of the HTG process are numerically analyzed and mechanistically discussed. The syngas cleaning/conditioning and Fischer-Tropsch (FT) synthesis are then detailed, aiming to produce liquid biofuels. The economic performance and environmental impacts of liquid biofuels using the HTG-FT route are evaluated. Finally, the challenges and prospects for future development in this field are presented. Overall, the maximum total gas yield in the HTG process is obtained at temperature, pressure, and residence time in the range of 450–500 °C, 28–30 MPa, and 30–60 min, respectively. The highest C5+ liquid hydrocarbon selectivity in the FT process is achieved at temperatures between 200 and 240 °C. Generally, effective conversion of biomass to syngas using the HTG process and its successful upgrading using the FT process can offer a viable route for producing liquid biofuels. Future studies should use HTG technology in the biorefinery context to maximize biomass valorization and minimize waste generation. © 2022 Elsevier Ltd
Publication Date: 2021
Renewable Energy (0960-1481) 171pp. 971-980
Despite its advantages, lignocellulosic butanol cannot become a real alternative without processes for obtaining credits from non-cellulosic fraction of lignocellulose. In this study, the process of “cellulosic butanol” was integrated with “hemicellulosic methane” process, i.e., anaerobic digestion (AD), for higher energy return on investment (EROI). Aqueous pretreatment was evaluated as a connecting chain between the processes. The alkaline (1% NaOH), acidic (1% H2SO4), and neutral (autohydrolysis) pretreatments were utilized at 140, 160, and 180 °C for bioenergy recovery from triticale straw. Enzymatic hydrolysis of the straw pretreated by alkaline (180 °C), dilute acid (140 °C), and autohydrolysis (180 °C) and fermentation of the hydrolysates by Clostridium acetobutylicum led to 13.6, 8.5, and 10.2 g/L acetone-butanol-ethanol (ABE), respectively. AD of the liquors remained after pretreatment by alkaline, dilute acid, and autohydrolysis led to 83–121, 240–247, and 380–430 mL/g VSS methane leading to more than 60% increase in EROI. © 2021 Elsevier Ltd
Publication Date: 2021
Advanced Materials Technologies (2365709X) 6(10)
It is predicted that the future of energy will mainly rely on batteries such as vanadium redox flow batteries (VRFBs), and its related research has already attracted significant attention. The primary function of a membrane in VRFBs is to control proton transport between the half-cells and to hinder admixing the anolyte and catholyte at the same time. However, to develop a low-cost and energy-efficient VRFB, other membrane roles are crucial. The combination of a highly stable backbone of polytetrafluoroethylene with hydrophilic perfluorinated-vinyl-polyether side chains equipped with sulfonic acid groups (Nafion membranes) has led to a breakthrough in the field. However, suffering from high cost and low selectivity, these perflurinated membranes are not properly qualified for VRFBs. Sulfonation of aromatic hydrocarbon polymers is suggested as cost-effective alternative chemistry for VRFBs’ membrane design. Further tunning the performance of the membrane and VRFB is obtained through designing their microstructure by different tools, especially adjusting the degree of sulfonation and degree of branching, utilizing additional membrane layers, and incorporation of particles in the polymer matrix. In this review, the studies performed to develop membranes for VRFBs are discussed as a road map for the development of advanced membranes qualified for VRFBs. © 2021 Wiley-VCH GmbH
Publication Date: 2021
Renewable and Sustainable Energy Reviews (1364-0321) 149
Bioenergy systems are expected to expand over the coming decades due to their potential to address energy security and environmental pollution challenges. Nevertheless, any renewable energy project can only survive if approved environmentally superior to its conventional counterparts. Life cycle assessment (LCA) is an internationally standardized and validated methodology to evaluate and quantify the environmental impacts of bioenergy systems. However, due to its methodological scope, the LCA method measures only the environmental consequences of the target products of energy systems. The LCA approach can neither allocate the environmental impacts at the component level nor measure the environmental impacts of intermediate products. These challenges can be substantially resolved by systematically integrating the LCA approach with the thermodynamically-rooted exergy, offering a powerful environmental sustainability assessment tool known as “exergoenvironmental analysis“. Due to the unique methodological and conceptual characteristics of exergoenvironmental analysis in revealing the possibilities and trends for improvement, it has recently received increasing attention to mitigate the environmental impacts of bioenergy systems. Therefore, this review is aimed to thoroughly summarize and critically discuss the evaluation of sustainability aspects of bioenergy systems based on exergoenvironmental analysis. The pros and cons of using exergoenvironmental analysis in bioenergy research are also outlined to identify possible future directions for the field. Overall, exergoenvironmental analysis can offer more detailed information on the environmental consequences of each flow and component of bioenergy production plants, thereby diagnosing the breakthrough points for additional environmental improvements. © 2021 Elsevier Ltd
Publication Date: 2021
Frontiers in Bioengineering and Biotechnology (22964185) 9
The bioconversion of lignocellulose into monosaccharides is critical for ensuring the continual manufacturing of biofuels and value-added bioproducts. Enzymatic degradation, which has a high yield, low energy consumption, and enhanced selectivity, could be the most efficient and environmentally friendly technique for converting complex lignocellulose polymers to fermentable monosaccharides, and it is expected to make cellulases and xylanases the most demanded industrial enzymes. The widespread nature of thermophilic microorganisms allows them to proliferate on a variety of substrates and release substantial quantities of cellulases and xylanases, which makes them a great source of thermostable enzymes. The most significant breakthrough of lignocellulolytic enzymes lies in lignocellulose-deconstruction by enzymatic depolymerization of holocellulose into simple monosaccharides. However, commercially valuable thermostable cellulases and xylanases are challenging to produce in high enough quantities. Thus, the present review aims at giving an overview of the most recent thermostable cellulases and xylanases isolated from thermophilic and hyperthermophilic microbes. The emphasis is on recent advancements in manufacturing these enzymes in other mesophilic host and enhancement of catalytic activity as well as thermostability of thermophilic cellulases and xylanases, using genetic engineering as a promising and efficient technology for its economic production. Additionally, the biotechnological applications of thermostable cellulases and xylanases of thermophiles were also discussed. Copyright © 2021 Ajeje, Hu, Song, Peter, Afful, Sun, Asadollahi, Amiri, Abdulkhani and Sun.
Publication Date: 2020
Industrial Crops and Products (09266690) 151
Hemicellulose is a cheap and abundant substrate for biofuel production. However, industrial scale production of biofuels from hemicellulose is relatively inefficient because of expensive pretreatment processes and poor pentoses utilization by most microorganisms. In this study, a cost-effective autohydrolysis process using water as the only reagent to hydrolyze lignocellulose was exploited. Sweet sorghum stalk was also utilized as an economic source of hemicellulose. The autohydrolyzed lignocellulosic compounds from sweet sorghum were used as substrate in acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobutylicum which is able to ferment pentoses and hexoses into ABE. Separation of 79 % of hemicellulose and roughly 20 % of cellulose from sweet sorghum stalk was detected as a desirable result for autohydrolysis at 210 °C; however, over-production of inhibitors made it an inappropriate pretreatment for ABE fermentation. No butanol production was detected in autohydrolysates of 210 °C, even after using detoxification methods for inhibitory compounds removal. On the other hand, only 20 % of sweet sorghum's bagasse hemicellulose was separated at 150 °C; yet, it was detected as the most desirable hydrolysate for ABE fermentation. Nevertheless, inherent inefficiency of C. acetobutylicum to ferment xylo-oligomers (as the sole carbon source) led to less than 1 g/L of ABE production in autohydrolysates at 150 °C. Co-fermentation of these hydrolysates with sorghum grain starch was investigated as a solution and it significantly increased the ABE production up to 8.3 g/L. Furthermore, the synergistic effect of co-fermentation was investigated where 35 % improvement in ABE production was detected. Accordingly, xylose utilization increased from 45 % to 80 %. © 2020 Elsevier B.V.
Publication Date: 2020
Renewable Energy (0960-1481) 160pp. 269-277
Potato peel waste (PPW) is a carbohydrate-rich waste from potato industries, which is an environmental threat worldwide. In this study, it was evaluated for biobutanol production via acetone-butanol-ethanol fermentation by Clostridium acetobutylicum. The results showed that PPW contained a considerable amount of glycoalkaloids, severe inhibitors for the bacterium. Thus, three processes, i.e., dilute acid pretreatment (Process I), the inhibitors extraction followed by dilute acid hydrolysis (Process II) and ethanol organosolv pretreatment (Process III), were employed before hydrolysis and fermentation to produce ABE. The extraction of glycoalkaloids with ethanol, dilute acid hydrolysis at 180 °C for 60 min, and enzymatic hydrolysis led to a hydrolysate with 36 g/L glucose, which was successfully fermented to 11.6 g/L ABE. In process II, the organosolv pretreatment led to the removal of the major fraction of inhibitors, in the range of 77–88% of glycoalkaloids. The enzymatic hydrolysis of PPW pretreated with 75% ethanol at 180 °C for 60 min resulted in a fermentable hydrolysate with 38 g/L glucose. The fermentation of overall hydrolysate resulted in a high ABE concentration of 24.8 g/L, indicating that PPW is an appropriate substrate for butanol production after the removal of its bacterial inhibitors. © 2020 Elsevier Ltd
Publication Date: 2020
Biotechnology and Bioengineering (00063592) 117(2)pp. 392-405
Clostridium acetobutylicum is widely used for the microbial production of butanol in a process known as acetone–butanol–ethanol (ABE) fermentation. However, this process suffers from several disadvantages including high oxygen sensitivity of the bacterium which makes the process complicated and necessitate oxygen elimination in the culture medium. Nesterenkonia sp. strain F has attracted interests as the only known non-Clostridia microorganism with inherent capability of butanol production even in the presence of oxygen. This bacterium is not delimited by oxygen sensitivity, a challenge in butanol biosynthesis, but the butanol titer was far below Clostridia. In this study, Nesterenkonia sp. strain F was cocultivated with C. acetobutylicum to form a powerful “coculture” for butanol production thereby eliminating the need for oxygen removal before fermentation. The response surface method was used for obtaining optimal inoculation amount/time and media formulation. The highest yield, 0.31 g/g ABE (13.6 g/L butanol), was obtained by a coculture initiated with 1.5 mg/L Nesterenkonia sp. strain F and inoculated with 15 mg/L C. acetobutylicum after 1.5 hr in a medium containing 67 g/L glucose, 2.2 g/L yeast extract, 4 g/L peptone, and 1.4% (vol/vol) P2 solution. After butanol toxicity assessment, where Nesterenkonia sp. strain F showed no butanol toxicity, the coculture was implemented in a 2 L fermenter with continual aeration leading to 20 g/L ABE. © 2019 Wiley Periodicals, Inc.
Publication Date: 2020
Biochemical Engineering Journal (1873295X) 164
The microbial pathway of butanol biosynthesis is a unique route for the production of a biomass-derived advanced biofuel with high potential to be utilized in place of the fossil fuels. In the present study, Nesterenkonia sp. strain F was applied as a beneficial partner for Clostridium acetobutylicum in “starch-to-butanol process”. The capability of Nesterenkonia sp. strain F in secreting organic solvent-tolerant amylase was utilized for upgrading the yield of solvent, i.e., acetone, butanol, and ethanol (ABE), production under aerobic conditions. Monitoring the amylolytic activity and glucose concentration throughout the micro-aerobic co-culture revealed higher amylase activity and glucose concentration in comparison with the monoculture. The co-culture led to 63% higher amylase activity through the microaerobic cultivation on starch. After optimizing the conditions with response surface methodology (RSM), 10.6 g/L butanol was produced from untreated potato starch (UPS) with a high yield of 0.23 g ABE/g starch, leading to 30% improvement in ABE production. To assess its performance at larger scale, the fermentation was conducted in a 5 L fermenter continually aerated with a rate of 0.05 vvm and 150 rpm. This led to production of 9.7 g/L butanol, 5.0 g/L acetone, and 0.3 g/L ethanol with a yield and productivity of 0.20 g/g and 0.21 g/L.h, respectively. Furthermore, ABE production from tannin-containing sorghum grain was improved by about 3-fold. © 2020 Elsevier B.V.
Publication Date: 2020
Fuel (0016-2361) 263
Butanol attracted interests as a drop-in biofuel obtainable from cellulosic wastes. However, the process typically used for cellulose bioconversion, i.e., separate hydrolysis and fermentation (SHF) of pretreated cellulose (Process I), is insufficient for energy-efficient production of fuel grade butanol due to the limited obtainable butanol titer. Recently, post-hydrolysis of chemically formed water-soluble cellulose oligomers was suggested for acetone-butanol-ethanol (ABE) production in SHF mode of operation (Process II). In this study, it was found that simultaneous saccharification and fermentation of the soluble oligomers (oligomeric-SSF) (Process III) and simultaneous co-saccharification and fermentation (SCSF) of soluble oligomers along with regenerated cellulose (Process IV) are promising alternatives for upgrading the titer and yield of cellulosic butanol production by Clostridium acetobutylicum. In Process III, utilizing the oligomeric hydrolysate obtained through dilute acid hydrolysis at 120 °C for 60 min using 1% acid through oligomeric-SSF led to 14.2 g/L ABE production, i.e., 65% higher than Process I. In addition, using the oligomeric hydrolysate in SCSF resulted in 24 g/L ABE (16 g/L butanol) production with an overall yield of 182 g ABE/kg cellulose. Process IV showed 191% higher titer and 14% higher yield of ABE production, compared with Process I. © 2019 Elsevier Ltd
Publication Date: 2020
Industrial Crops and Products (09266690) 145
Different process alternatives were assessed for production of hemicellulosic and cellulosic butanol from sweet sorghum bagasse (SSB) based on integration of autohydrolysis, enzymatic hydrolysis, and ABE fermentation. The liquor obtained through single or two-stage autohydrolysis was subjected to post-hydrolysis using a commercial hemicellulases blend and fermentation by Clostridium acetobutylicum. The pretreated solids obtained at each stage of autohydrolysis were also used for ABE production through separated hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) using a commercial cellulase blend. The two-stage autohydrolysis (at 150 °C for 30 min; 120 °C for 60 min) followed by enzymatic post-hydrolysis resulted in 6.6 g/L sugar and fermented to 4.6 g/L ABE. On the other hand, enzymatic hydrolysis and ABE fermentation of the pretreated SSB led to 4.7–5.4 g/L ABE. In this process, 32 g hemicellulosic and 85 g cellulosic ABE were produced from each kg SSB. Besides, other thirteen process alternatives were compared based on the overall yield of ABE production from SSB. In the most compact process, the four enzymatic hydrolysis and fermentation stages were combined into a single stage named “simultaneous co-saccharification and fermentation (SCSF)" leading to 21−22 g ABE/kg SSB. © 2019 Elsevier B.V.
Publication Date: 2020
Biofuel Research Journal (22928782) 7(4)pp. 1256-1266
Butanol is a key microbial product that provides a route from renewable carbohydrate resources to a "drop-in" liquid biofuel, broadening its market in the near future. The acceptable performance of butanol as a neat or a blended fuel in different engines both from the technical and environmental points of view has attracted a wide range of research for reviving the old acetone-butanol-ethanol (ABE) fermentation. In this review, recent findings on fuel characteristics of butanol, different generations of substrate for large scale butanol production, and alternative process designs for upstream, mainstream, and downstream operations have been critically reviewed and discussed. In the upstream, studies devoted to designing and optimization of pretreatments based on prerequisites of butanol production, e.g., maximizing cellulose and hemicellulose recovery and minimizing lignin degradation, are presented. In the mainstream, different microbial systems and process integrations developed for facilitating ABE production (e.g., in-situ butanol removal) are scrutinized. Finally, innovations in ABE recovery and purification as "Achilles Heel" of butanol production processes which directly controls the energy return on investment (EROI), are reviewed and discussed © 2020, Biofuel Research Journal. All Rights Reserved.
Publication Date: 2020
Waste Management (0956-053X) 118pp. 45-54
Co-processing of lignocellulosic wastes, e.g., garden and paper wastes, and the organic matters fraction of municipal solid waste (OMSW) in an integrated bioprocess is a possible approach to realize the potential of wastes for biobutanol production. Dilute acid pretreatment is a multi-functional stage for breaking the recalcitrant lignocellulose's structure, hydrolyzing hemicellulose, and hydrolyzing/solubilizing starch, leading to a pretreated solid and a rich hydrolysate. In this study, dilute-acid pretreatment of the combination of wastepaper and OMSW, composite I, as well as garden waste and OMSW, composite II, at severe conditions resulted in “pretreatment hydrolysates” containing 33.7 and 19.4 g/L sugar along with 18.9 and 33.2 g/L soluble starch, respectively. In addition, the hydrolysis of solid remained after the pretreatment of composite I and II resulted in “enzymatic hydrolysates” comprising 19.4 and 33 g/L sugar, respectively. The fermentation of the pretreatment hydrolysates and enzymatic hydrolysates resulted in 3.5 and 6.4 g/L ABE from composite I and 15 and 5.2 g/L ABE from composite II, respectively. In this process, 148 and 173 g ABE (60 and 100 g gasoline equivalent/kg) was obtained from each kg composite I and composite II, respectively, where co-processing of OMSW with lignocellulosic wastes resulted in 10 and 49% higher ABE than that produced from the individual substrates. © 2020 Elsevier Ltd
Publication Date: 2019
2025 29th International Computer Conference, Computer Society of Iran, CSICC 2025 pp. 109-133
Renewable resources should gradually take the responsibility of supplying global energy demands. Alcohols are among the chemicals that can be produced from renewable resources and utilized as liquid fuels with a number of advantages. However, a diverse set of qualifications is required for the alcoholic fuels. Ethanol is industrially produced from sugary and starchy resources. Nevertheless, there are obstacles standing in the way of fuel-grade ethanol progression. Recently, butanol, the product of acetone-butanol-ethanol (ABE) fermentation, has attracted interest for its potential as a fuel. ABE fermentation with clostridia has interesting features for the bioconversion of wastes. Unlike most ethanol-producing microorganisms, clostridia are able to produce the solvents from pentoses and starch as effective as hexoses. This chapter focuses on different aspects of biobutanol production. After summarizing the history, traditional and recently patented technologies are reviewed. Alternative substrates and the important features of microorganisms are discussed. The chapter concludes with advances obtained in lignocelluloses utilization and novel microorganisms. © 2019 Elsevier Inc. All rights reserved.
Publication Date: 2019
Cellulose (09690239) 26(7)pp. 4479-4494
A process consisting of regeneration of crystalline cellulose, dilute-phosphoric acid hydrolysis of regenerated cellulose to soluble oligomers, and enzymatic post-hydrolysis of soluble oligomers in the absence of disturbing solid particles was evaluated as a process alternative for upgrading the obtainable sugar concentration and facilitating the long-term enzymatic hydrolysis of cellulose by utilizing soluble oligomers instead of insoluble particles. Cellulose was regenerated though phosphoric acid-acetone process, i.e., dissolution into 21 g/g acid at 50 °C for 60 min and precipitation by adding 41 g/g acetone. Regenerated cellulose was hydrolyzed at 120, 150 or 180 °C for 30 or 60 min using 0.5 or 1% phosphoric acid. After filtration, the hydrolysates were subjected to 10 or 15 FPU/g cellulase. Dilute-acid hydrolysis of regenerated cellulose with 0.5% acid at 180 °C, 30 min, and 10% solid loading resulted in an '‘oligomeric hydrolysate’' with 44.6 g/L soluble oligomers. Enzymatic posthydrolysis of soluble oligomers resulted in a '‘monomeric hydrolysate’' containing as high as 47 g/L glucose and cellobiose. In the hydrolysis, 429 g sugar was released at high concentration from one kg crystalline cellulose. The hydrolysates were subjected to fermentation by Clostridium acetobutylicum, where oligomeric hydrolysates showed poor fermentability. The fermentation of monomeric hydrolysates obtained by dilute-acid hydrolysis (120 °C, 60 min, and 0.5% acid) and post-hydrolysis (15 filter paper unit/g) resulted in 6.1 g/L acetone-butanol-ethanol. Besides other potential advantages, this hydrolysis approach resulted in relatively high concentration of glucose which may facilitate cellulosic butanol production. © Springer Nature B.V. 2019.
Publication Date: 2018
Energy Conversion and Management (0196-8904) 157pp. 396-408
The biodegradable fraction of municipal solid waste (BMSW), dominantly composed of starchy and lignocellulosic materials, has high potential to be used for liquid biofuel production. Hot water or dilute acid treatment at high temperature was utilized for the solubilization or hydrolysis of the starch fraction and pretreatment of the lignocellulosic fraction. The treatment liquor, which was rich in sugars and starch, was evaluated for acetone, butanol, and ethanol (ABE) production by Clostridium acetobutylicum, and it was found that phenolic compounds, especially tannins, critically inhibited the butanol production. To improve ABE production, the extraction of phenolic compounds prior to hot water or dilute acid treatment was evaluated. Among the evaluated extractants, i.e., acetone, ethanol, butanol, and water, ethanol showed the highest amount of tannin extraction, resulting in an 87% reduction in tannin content. Dilute acid treatment of the ethanol extracted BMSW at 140 °C for 60 min resulted in a liquor containing 23 g/L glucose and 41 g/L soluble starch, which was fermented to the highest ABE concentration of 17 g/L with productivity of 0.24 g/L/h. The fermentation of liquor obtained by dilute acid treatment of butanol, acetone, and water-extracted BMSW was accompanied by 9, 6, and 4 g/L ABE production. Even by hot water treatment, the liquor obtained from ethanol extracted BMSW was fermented to the highest ABE concentration of 8 g/L. In addition to the liquor, the pretreated lignocellulosic material was subjected to enzymatic hydrolysis and ABE fermentation, leading to production of 5–6 g/L ABE. This process resulted in the production of 83.9 g butanol, 36.6 g acetone, and 20.8 g ethanol from each kg of BMSW. Moreover, the co-production of ethanol by ABE fermentation reduced concerns about organic extractor loss in the extraction process, which was inescapable in the tannin extraction process. © 2017 Elsevier Ltd
Publication Date: 2018
Journal of Cleaner Production (0959-6526) 193pp. 459-470
To move biobutanol toward a commercialized biofuel, its production process should be developed based on renewable and cost-effective carbon sources. In this study, it was shown that cotton, a commodity that typically ends in landfill sites or incinerators, can be utilized as a feasible source after the phosphoric acid-acetone process. The treatment with phosphoric acid (19 g/g) resulted in 94% cotton dissolution after 60 min, and the addition of acetone (41 g/g) was accompanied by 97% precipitation. Enzymatic hydrolysis of regenerated cellulose (15 filter paper unit per mL (FPU/mL)) followed by fermentation by Clostridium acetobutylicum resulted in 5.4 g/L acetone-butanol-ethanol (ABE). In this process, 208 g acid and 138 FPU cellulase were used for production of each g ABE. Increasing enzyme dosage to 25 FPU/g resulted in 79% higher butanol production (161 g ABE/kg). Through cyclic acid re-concentration, phosphoric acid consumption decreased to 82 g/g ABE. Furthermore, by applying an additional dilute phosphoric acid pretreatment, the enzyme consumption reduced to 113 FPU/g ABE. © 2018 Elsevier Ltd
Publication Date: 2018
Bioresource Technology (0960-8524) 270pp. 702-721
Butanol is acknowledged as a drop-in biofuel that can be used in the existing transportation infrastructure, addressing the needs for sustainable liquid fuel. However, before becoming a thoughtful alternative for fossil fuel, butanol should be produced efficiently from a widely-available, renewable, and cost-effective source. In this regard, lignocellulosic materials, the main component of organic wastes from agriculture, forestry, municipalities, and even industries seems to be the most promising source. The butanol-producing bacteria, i.e., Clostridia sp., can uptake a wide range of hexoses, pentoses, and oligomers obtained from hydrolysis of cellulose and hemicellulose content of lignocelluloses. The present work is dedicated to reviewing different processes containing pretreatment and hydrolysis of hemicellulose and cellulose developed for preparing fermentable hydrolysates for biobutanol production. © 2018 Elsevier Ltd
Publication Date: 2018
Bioresource Technology (0960-8524) 270pp. 236-244
Municipal solid waste (MSW) was used as a source for biobutanol production via acetone, butanol, and ethanol (ABE) fermentation. Organosolv pretreatment was used for simultaneous extraction of inhibitors, particularly tannins, and pretreatment of lignocellulosic fraction prior to hydrolysis. The hydrolysates of the pretreated MSW contained appreciable amounts of sugars and soluble starch together with a tolerable amount of inhibitors for Clostridium acetobutylicum. The hydrolysate obtained from MSW pretreated with 85% ethanol at 120 °C for 30 min fermented to the highest ABE concentration of 13.06 g/L with the yield of 0.33 g/g carbon source. Through this process, 102.4 mg butanol, 40.16 mg acetone, and 13.14 mg ethanol were produced from each g of organic fraction of MSW (OFMSW). The pretreatment at mild conditions with higher ethanol concentration accompanied with the lowest glucose yield (0.145 g/g) and the highest starch recovery resulted in the uppermost ABE yield of 0.16 g/g OFMSW. © 2018 Elsevier Ltd
Publication Date: 2018
Industrial Crops and Products (09266690) 125pp. 473-481
Sweet sorghum plant, a widely grown energy crop, was utilized through a biorefinery process, by which its grains were hydrolyzed by the crude amylases produced from its bagasse. The hemicellulosic part of the bagasse was hydrolyzed with 0.5–1.0% sulfuric acid at 140–180 °C for 30–60 min and applied for amylase production using halotolerant bacterium Nesterenkonia sp. strain F. In the hydrolysate obtained at 140 °C for 60 min using 1% acid, Nesterenkonia showed 73.3 U/mL amylase activity by the consumption of 16.2 g/L xylose and 8.3 g/L other sugars. Supplementation of the hydrolysates with sorghum grain resulted in 38–67% higher amylase production. Furthermore, addition of biocompatible surfactants of Tween 20 and Tween 80 (0.1 g/L) increased the activity to 93 and 97 U/mL, respectively. The resulting crude enzyme was used in the process of ethanol production from both tannin-containing and tannin-free sorghum grains (6%), leading to 17.7 and 17.0 g/L bioethanol production, respectively. Through the cultivation of Nesterenkonia on the hemicellulosic hydrolysates, 5–10 g/L volatile fatty acids (VFA), 0.36–0.69 g/L acetone-butanol-ethanol (ABE), and 468–721 mg/L single cell protein (SCP) were also produced. The obtained SCP contained most of the essential amino acids and relatively high amounts of phenylalanine (8%), threonine (7%), methionine (6%), and lysine (6%). © 2018 Elsevier B.V.
Publication Date: 2017
Journal of Cleaner Production (0959-6526) 166pp. 1428-1437
Acetone–butanol–ethanol (ABE) production from grains, bagasse, and juice of sweet sorghum was conducted by Clostridium acetobutylicum. Delignification with acetone, one of the ABE fermentation products, was evaluated as a pretreatment for the improvement of ABE production from bagasse. Different modes of hydrolysis and fermentation of “separate hydrolysis and fermentation (SHF)” (process I), “simultaneous saccharification and fermentation (SSF)” (process II), and “simultaneous saccharification and co-fermentation (SSCF)” (process III) were compared for ABE production from delignified bagasse. Direct ABE fermentation of stalks without juice extraction was also evaluated (process IV). Along with the stalks, the starchy grains of the sorghum plant were directly utilized in the ABE fermentation. Total concentration of acetone, butanol, and ethanol (ABE) of 10.6 g/L, containing 3.17 g/L acetone, 6.34 g/L butanol, and 1.06 g/L ethanol, was obtained through SSF process at pH 5.8 and 37 °C from the bagasse pretreated at 180 °C for 60 min. Through the SSCF process, solvents production was increased by 27–36% as compared to the SSF. From each kg sweet sorghum plant, 156, 136, 101, and 110 g total acetone, butanol, and ethanol (g ABE) was produced through process I, II, III, and IV, respectively. It was concluded that utilizing all parts of sweet sorghum plant, as an energy crop, is a promising approach for ABE production. © 2017 Elsevier Ltd
Publication Date: 2017
Industrial Crops and Products (09266690) 108pp. 225-231
Industrial scale production of biobutanol has been hampered by substrate cost and availability. Sweet sorghum grain is an inexpensive substrate for acetone-butanol-ethanol (ABE) production by Clostridium acetobutylicum. Amylolytic activity of C. acetobutylicum eliminates the need for the hydrolysis of starchy grain prior to fermentation. However, untreated grain contains phenolic compounds, i.e. tannins, which exhibit inhibitory effects against amylolytic activity and ABE fermentation. Less than 3 g/L ABE was obtained from untreated sweet sorghum grain at different substrate concentrations. Concentration of 0.2 mM gallic acid equivalent (GAE) of sorghum tannins was detected as the critical concentration which inhibits severely ABE fermentation. Applying a multi-stage hot water treatment resulted in tannins removal and significant enhancement in total ABE production up to 18 g/L. For efficient butanol production from 40, 60, and 80 g/L sorghum grain, hot water treatment with two, five, and six stages were found to be essential for efficient butanol production, respectively. Moreover, the amylolytic activity of C. acetobutylicum was inhibited by sorghum grain tannins, more than twice as high as the effects on the ABE fermentation pathway. Furthermore, unlike most substrates, sweet sorghum grain could provide all nutrients required for ABE fermentation, eliminating the need for supplementing expensive additional nutrients. © 2017 Elsevier B.V.
Publication Date: 2016
Applied Energy (0306-2619) 168pp. 216-225
Development of efficient and cost-effective pretreatment prior to hydrolysis is essential for the economical production of biobutanol from lignocelluloses. In this study, acetone pretreatment with a number of advantages over the other pretreatments was used to improve enzymatic hydrolysis and fermentation with Clostridium acetobutylicum for acetone-butanol-ethanol (ABE) production from sweet sorghum bagasse (SSB). Using the pretreatment at 180 °C for 60 min, the yield of enzymatic hydrolysis of SSB was improved to 94.2%, leading to a hydrolysate with 36.3 g/L total sugar, which was subsequently fermented to 11.4 g/L ABE. This process resulted in the production of 78 g butanol, 35 g acetone, 12 g ethanol, 28 g acetic acid, and 6 g butyric acid from each kg of SSB. Through the pretreatment, 143 g lignin per kg of SSB was dissolved into the solvent, with the potential to be recovered as unaltered pure lignin. Furthermore, the co-production of acetone by the ABE fermentation alleviated the concern about unavoidable solvent loss in the pretreatment, i.e., 24 g acetone/kg SSB, using an integrated process for biobutanol production from SSB. The energy equivalent obtained in the form of butanol and ethanol (72 g gasoline equivalent/kg SSB) was higher than that obtainable via ethanolic fermentation (less than 70 g/kg SSB). © 2016 Elsevier Ltd.
Publication Date: 2016
Industrial and Engineering Chemistry Research (15205045) 55(17)pp. 4836-4845
A two-stage pretreatment, i.e., autohydrolysis and organosolv delignification, was used prior to enzymatic hydrolysis and fermentation by Clostridium acetobutylicum for the improvement of acetone, butanol, and ethanol (ABE) production from rice straw, pine, and elm. Through the autohydrolysis, a liquid, "autohydrolysate", containing 2-7 g/L sugar and 13-27 g/L oligomer, and a pretreated solid were obtained. The solid was subjected to organosolv delignification leading to 490-600 g of pretreated lignocelluloses (70%-74% cellulose) and 100-140 g lignin from each kilogram of lignocelluloses. The pretreated lignocelluloses were hydrolyzed to "cellulosic hydrolysates" and fermented to 6-10 g/L ABE. Through this process, 70-123 g of ABE was produced from each kilogram of lignocelluloses. "Overall hydrolysates" with further sugar concentrations of 16-50 g/L were obtained by hydrolysis of pretreated solid in the autohydrolysate. The yield of ABE production was progressed to 133 g ABE/kg elm by fermenting its overall hydrolysate. © 2016 American Chemical Society.
Publication Date: 2016
Scientific Reports (20452322) 6
The moderately halophilic bacterium Nesterenkonia sp. strain F, which was isolated from Aran-Bidgol Lake (Iran), has the ability to produce acetone, butanol, and ethanol (ABE) as well as acetic and butyric acids under aerobic and anaerobic conditions. This result is the first report of ABE production with a wild microorganism from a family other than Clostridia and also the first halophilic species shown to produce butanol under aerobic cultivation. The cultivation of Nesterenkonia sp. strain F under anaerobic conditions with 50 g/l of glucose for 72 h resulted in the production of 105 mg/l of butanol, 122 mg/l of acetone, 0.2 g/l of acetic acid, and 2.5 g/l of butyric acid. Furthermore, the strain was cultivated on media with different glucose concentrations (20, 50, and 80 g/l) under aerobic and anaerobic conditions. Through fermentation with a 50 g/l initial glucose concentration under aerobic conditions, 66 mg/l of butanol, 125 mg/l of acetone, 291 mg/l of ethanol, 5.9 g/l of acetic acid, and 1.2 g/l of butyric acid were produced. The enzymes pertaining to the fermentation pathway in the strain were compared with the enzymes of Clostridium spp., and the metabolic pathway of fermentation used by Nesterenkonia sp. strain F was investigated.
Publication Date: 2015
Chemical Engineering Science (00092509) 137pp. 722-729
Acetone, butanol, and ethanol (ABE) were produced from softwood pine and hardwood elm using autohydrolysis pretreatment, enzymatic hydrolysis, and fermentation by Clostridium acetobutylicum. The solid residue obtained by autohydrolysis, "pretreated solids", was hydrolyzed using a mixture of two commercially available cellulases leading to production of 162. g sugar from each kg pine and 295. g sugar from each kg elm in the form of "cellulosic hydrolysates". The fermentation of cellulosic hydrolysates resulted in the production of 79.3 and 117.6. g ABE from each kg of pine and elm, respectively. Through the autohydrolysis, between 187 to 195. g soluble sugars and oligomers was also released from each kg of the materials into the liquid streams named "autohydrolysates". Enzymatic hydrolysis of pretreated solid residue in the autohydrolysate liquor resulted in hydrolysates with total sugar concentration of 21-23. g/l, named "overall hydrolysates". In this process, 51% of the oligomers of pine autohydrolysate were converted to monomeric sugars and subsequently used for ABE production. Therefore, the fermentation of the overall hydrolysates resulted in the production of 104.5 and 43.4. g ABE from each kg of pine and elm, respectively. © 2015 Elsevier Ltd.
Publication Date: 2015
Bioprocess and Biosystems Engineering (16157605) 38(10)pp. 1959-1972
A suitable pretreatment is a prerequisite of efficient acetone-butanol-ethanol (ABE) production from wood by Clostridia. In this study, organosolv fractionation, an effective pretreatment with ability to separate lignin as a co-product, was evaluated for ABE production from softwood pine and hardwood elm. ABE production from untreated woods was limited to the yield of 81 g ABE/kg wood and concentration of 5.5 g ABE/L. Thus, the woods were pretreated with aqueous ethanol at elevated temperatures before hydrolysis and fermentation to ABE by Clostridium acetobutylicum. Hydrolysis of pine and elm pretreated at 180 °C for 60 min resulted in the highest sugar concentrations of 16.8 and 23.2 g/L, respectively. The hydrolysate obtained from elm was fermented to ABE with the highest yield of 121.1 g/kg and concentration of 11.6 g/L. The maximum yield of 87.9 g/kg was obtained from pine pretreated for 30 min at 150 °C. Moreover, structural modifications in the woods were investigated and related to the improvements. The woody biomasses are suitable feedstocks for ABE production after the organosolv pretreatment. Effects of the pretreatment conditions on ABE production might be related to the reduced cellulose crystallinity, reduced lignin and hemicellulose content, and lower total phenolic compounds in the hydrolysates. © 2015 Springer-Verlag Berlin Heidelberg.
Publication Date: 2014
BioMed Research International (23146141) 2014
Organosolv pretreatment was used to improve solid-state anaerobic digestion (SSAD) formethane production fromthree different lignocellulosic substrates (hardwood elm, softwood pine, and agricultural waste rice straw). Pretreatments were conducted at 150 and 180°C for 30 and 60 min using 75% ethanol solution as an organic solvent with addition of sulfuric acid as a catalyst. The statistical analyses showed that pretreatment temperature was the significant factor affecting methane production. Optimum temperature was 180°C for elmwood while it was 150°C for both pinewood and rice straw. Maximum methane production was 152.7, 93.7, and 71.4 liter per kg carbohydrates (CH), which showed up to 32, 73, and 84% enhancement for rice straw, elmwood, and pinewood, respectively, compared to those from the untreated substrates. An inverse relationship between the total methane yield and the lignin content of the substrates was observed. Kinetic analysis of the methane production showed that the process followed a first-order model for all untreated and pretreated lignocelluloses. Copyright © 2014 Safoora Mirmohamadsadeghi et al.
Publication Date: 2014
Bioresource Technology (0960-8524) 152pp. 450-456
Acetone-butanol-ethanol (ABE) was produced from rice straw using a process containing ethanol organosolv pretreatment, enzymatic hydrolysis, and fermentation by Clostridium acetobutylicum bacterium. Pretreatment of the straw with 75% (v/v) aqueous ethanol containing 1% w/w sulfuric acid at 150. °C for 60. min resulted in the highest total sugar concentration of 31. g/L in the enzymatic hydrolysis. However, the highest ABE concentration and productivity (10.5. g/L and 0.20. g/L. h, respectively) were obtained from the straw pretreated at 180. °C for 30. min. Enzymatic hydrolysis of the straw pretreated at 180. °C for 30. min with 5% solid loading resulted in glucose yield of 46.2%, which was then fermented to 80.3. g butanol, 21.1. g acetone, and 22.5. g ethanol, the highest overall yield of ABE production. Thus, the organosolv pretreatment can be applied for efficient production of the solvents from rice straw. © 2013 Elsevier Ltd.
Publication Date: 2013
Industrial and Engineering Chemistry Research (15205045) 52(33)pp. 11494-11501
Pretreatment with N-methylmorpholine-N-oxide (NMMO), phosphoric acid, and sodium hydroxide was evaluated for improvement of dilute-acid hydrolysis of cotton fiber, the most difficult to break down cellulose. The pretreatments improved the yield of glucose formation by acid hydrolysis. Compared to the other methods, phosphoric acid pretreatment resulted in higher glucose yields and minimal byproduct formations by hydrolysis under milder conditions. Furthermore, the solid residue of the hydrolysis was subjected to enzymatic hydrolysis in order to convert the remaining cellulose to glucose. Different combinations of parameters in dilute-acid and enzymatic hydrolysis were considered for obtaining a high glucose yield with minimal enzyme loading. A process involving phosphoric acid pretreatment, dilute-acid hydrolysis, and enzymatic hydrolysis using only 5 FPU/g cellulase and 10 IU/g β-glucosidase resulted in total glucose yield of 95.4%, and fermentation of the hydrolysates resulted in a yield of 458 g of ethanol/kg of initial cellulose (0.47 g ethanol/g glucose). © 2013 American Chemical Society.
Publication Date: 2013
Fuel (0016-2361) 112pp. 8-13
Rice straw was hydrolyzed and fermented to acetone, butanol, and ethanol by Clostridium acetobutylicum bacterium. Concentrated phosphoric acid and alkaline treatment with NaOH were used for pretreatment of the straw prior to enzymatic hydrolysis using commercial cellulase and β-glucosidase. The enzymatic hydrolysates were then anaerobically fermented by C. acetobutylicum. Hydrolysis of the alkaline pretreated straw resulted in production of 163.5 g glucose from each kg of untreated rice straw which was then fermented to 45.2 g butanol, 17.7 g acetone, and 1.2 g ethanol. Additionally, concentrated phosphoric acid pretreatment and subsequent hydrolysis resulted in production of 192.3 g glucose from each kg straw from which 44.2 g butanol, 18.2 g acetone, and 0.6 g ethanol were produced after 72 h fermentation. Increasing the produced ABE from less than 10 g to higher than 62 g from each kg straw by the treatments suggested the alkaline and phosphoric acid pretreatments as promising processes for efficient production of ABE from rice straw. © 2013 Elsevier Ltd. All rights reserved.
Publication Date: 2010
Carbohydrate Research (00086215) 345(15)pp. 2133-2138
5-Hydroxymethylfurfural (HMF) and furfural, both of which can be derived from renewable sources, are key components for the production of different chemicals and fuels. In this study, rice straw, a cheap, abundant, and mainly unused agricultural waste, is converted to furans by a dilute acid hydrolysis process. The highest yield of HMF in a single-phase hydrolysis was 15.3 g/kg straw, attained at 180 °C during 3 h with 0.5% sulfuric acid, while the maximum yield of furfural, 59 g/kg straw, was obtained at 150 °C during 5 h. Different extracting solvents, including 2-PrOH, 1-BuOH, methyl isobutyl ketone (MIBK), and acetone at 180 °C for 3 h as well as tetrahydrofuran (THF) at 150 °C for 5 h were examined in biphasic systems. Use of the solvents generally improved the production of HMF compared to the single aqueous phase process. The best results of HMF production, more than 59 g/kg straw, were obtained in the systems containing either 2-PrOH or 1-BuOH. Using THF as an extracting solvent, a relatively high furfural yield, 118.2 g/kg straw, was obtained, and 96% of furfural produced in this system was extracted into THF during the process. © 2010 Elsevier Ltd. All rights reserved.
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