Articles
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
Bioresource Technology (09608524)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
Materials Today Communications (23524928)44
During the last decade, researchers have developed synthetic substances that mimic the properties of enzymes due to the limitations of natural enzymes. This has led to the creation of nanozymes, nanomaterials with enzyme-like catalytic properties. Herein, iron oxide nanozymes (Fe3O4) with peroxidase-like activity (POD) were synthesized via a single-step solvothermal process. Subsequently, these nanozymes were surface-functionalized with nanocellulose, a biocompatible and biodegradable biopolymer, to examine its influence on POD-like activity. A significant 42.7 % increase in specific POD-like activity was observed for Fe3O4 nanozymes functionalized with nanocellulose (Fe3O4@NC), accompanied by a six-fold enhancement in maximum velocity (vmax) for the 3,3′,5,5′-tetramethylbenzidine (TMB) substrate. The Fe3O4@NC nanozymes were capable of utilizing intracellular hydrogen peroxide (H2O2) and generating highly reactive oxygen species through the Fenton reaction and enhanced POD-like activity, leading to the elimination of MCF-7 breast cancer cells via chemodynamic therapy. Furthermore, the incorporation of doxorubicin, an anticancer drug, into Fe3O4@NC nanozymes demonstrated a synergistic effect on chemo/chemodynamic cancer therapy. Concluded, the Fe3O4@NC nanozyme/nanocarrier exhibits considerable potential as an effective therapeutic agent for cancer cells, particularly when employed in conjunction with chemo/chemodynamic therapy. © 2025 Elsevier Ltd
Rezaie, H.,
Abbasi kajani, A.,
Jafarian, F.,
Asgari, S.,
Taheri kafrani, A.,
Bordbar, A. Journal of Biotechnology (01681656)387pp. 23-31
Enzyme immobilization in membrane bioreactors has been considered as a practical approach to enhance the stability, reusability, and efficiency of enzymes. In this particular study, a new type of hybrid membrane reactor was created through the phase inversion method, utilizing hybrid of graphene oxide nanosheets (GON) and polyether sulfone (PES) in order to covalently immobilize the Candida rugosa lipase (CRL). The surface of hybrid membrane was initially modified by (3-Aminopropyl) triethoxysilane (APTES), before the use of glutaraldehyde (GLU), as a linker, through the imine bonds. The resulted enzymatic hybrid membrane reactors (EHMRs) were then thoroughly analyzed by using field-emission scanning electron microscopy (FE-SEM), contact angle goniometry, surface free energy analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, attenuated total reflection (ATR), and energy-dispersive X-ray (EDX) spectroscopy. The study also looked into the impact of factors such as initial CRL concentration, storage conditions, and immobilization time on the EHMR's performance and activity, which were subsequently optimized. The results demonstrated that the CRLs covalently immobilized on the EHMRs displayed enhanced pH and thermal stability compared to those physically immobilized or free. These covalently immobilized CRLs could maintain over 60% of their activity even after 6 reaction cycles spanning 50 days. EHMRs are valuable biocatalysts in developing various industrial, environmental, and analytical processes. © 2024 Elsevier B.V.
