Microchemical Journal (0026265X)
In this study, ultrasound-assisted emulsification microextraction with solidification of a sedimentary drop of ionic liquid (USAEME-SSIL) was used to extract fat-soluble vitamins from aqueous samples. For the first time, an amphiphilic ionic liquid, 2-thiahexadecyl-1-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([mimSC16][NTf2]), was employed as a solvent in USAEME-SSIL method. The amounts of extracted vitamins were determined by high performance liquid chromatography (HPLC) and Ultraviolet –Visible detection. Effect of several parameters on USAEME-SSIL extraction efficiency including type and amount of ionic liquid, pH, temperature, time of sonication and centrifuging were optimized. The optimum conditions were 20 mg [mimSC16][NTf2], solution temperature of 50 °C, 10.00 mL of sample solution with pH = 6 containing 15 % (w/v) NaCl, sonication time of 4 min and centrifugation at 4000 rpm for 7 min. The calibration curves were plotted using the internal standard method. The findings indicated that all curves displayed linearity within the range of 0.50 to 4.00 mg L -1 (R2 > 0.9982). This technique demonstrated excellent consistency (%RSD ≤ 1.21), low limits of detection (LOD < 76.50 µg/L), high accuracy (recoveries > 92.40 %), and significant enrichment factors (EF > 13.50). The application of this method proved successful in analyzing fat-soluble vitamins in pharmaceutical samples. © 2024 Elsevier B.V.
Hemati S.,
Heidari, M.,
Momenbek, F.,
Khodabakhshi a., A.,
Fadaei A. PLoS ONE (19326203)(9 September)
Oil spills from pipeline accidents can have long-lasting health effects on residents of polluted regions. Assessing the potential health risk of these accidents is crucial for effective environmental health management. This study analyzed the concentration of 2-OHNAP in urine and hair as biomarkers of PAHs exposure among the people living in a region with frequent oil pipeline incident in Iran. Fifty pairs of hair and urine samples were collected from residents along with demographic information and dietary habits via a questionnaire. The concentration of 2-OHNAP was analyzed using high performance liquid chromatography coupled with fluorescence detector (HPLC-FLD). 2-OHNAP was detected in 100% of urine and 88% of hair samples. The mean concentration of 2-OHNAP in urine was 16.65 ± 21.98 μg/g creatinine and in hair was 8.16±7.62 ng/g dry weight (dw). However, there was no significant correlations between the levels of 2-OHNAP in urine and hair. The mean values of HQ and CR were below 1 and 10−6, respectively. Moreover, some simulated health risk indices were near the threshold levels, and the carcinogenic risk above 70% of the simulated CRs was above 10−6 as well. Therefore, the health risk attributed to the exposure to the parent compound of 2-OHNAP in the study area is currently acceptable, but it is not negligible and may be worsened in the future. This study provides a valuable scientific information for regional decision makers and stakeholders about human health programs and identification of environmental health priorities. © 2024 Hemati et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Kazemi, Z.,
Amiri rudbari, H.,
Moini, N.,
Momenbek, F.,
Carnamucio, F.,
Micale, N. Molecules (14203049)29(2)
Indole is an important element of many natural and synthetic molecules with significant biological activity. Nonetheless, the co-presence of transitional metals in organic scaffold may represent an important factor in the development of effective medicinal agents. This review covers some of the latest and most relevant achievements in the biological and pharmacological activity of important indole-containing metal complexes in the area of drug discovery. © 2024 by the authors.
Journal of Chromatography A (00219673)
A novel azo-linked porous organic polymer (AL-POP) was synthesized from caffeic acid and benzidine via an azo-coupling reaction and characterized by FTIR, SEM-EDS, BET, TGA, XRD and zeta potential analysis. AL-POPs were incorporated into melamine sponges and used for pipette tip micro solid-phase extraction (PT-MSPE) of six types of B vitamins (including thiamine, riboflavin, nicotinamide, pyridoxine, folic acid, and cyanocobalamin). After extraction, the samples were analyzed using high performance liquid chromatography-diode array detection (HPLC-DAD) system. The effect of AL-POP composition on the extraction efficiency (EE) of vitamins was investigated and benzidine to caffeic acid mol ratio of 1.5, 3.35 mmol of NaNO2 and reaction time of 8 h were selected as optimum conditions. The efficiency of the extraction process was improved by optimizing various parameters such as the amount of sorbent, pH and ionic strength of the sample, sample volume, number of sorption and desorption cycles, type of wash solvent, and type and volume of eluent solvent. Linearity (R2≥0.9987), Limit of detection (LOD) (11.88–18.97 ng/mL), limit of quantification (LOQ) (39.62–63.23 ng/mL), and enrichment factor (EF) (1.27–4.31) were obtained using calibration curves plotted under optimum conditions. Recovery values of these six B vitamins in the spiked multivitamin syrup samples varied from 80.01% to 108.35%, with a relative standard deviation (RSD) below 5.44%. Eventually, the optimized method was successfully used to extract and quantify the B vitamins in multivitamin syrup and non-alcoholic beer. © 2024 Elsevier B.V.
International Journal of Environmental Science and Technology (17351472)21(15)pp. 9377-9390
Antibiotics as micro-pollutants enter the environment through pharmaceutical effluents, human urine and faeces, and sweat and increase antibiotic resistance genes. The purpose of this study was to isolate amoxicillin (AMX) and co-amoxiclav (AMC) biodegrading bacteria from agricultural soil. From 15 isolates, Stenotrofomonas maltophilia strain DF1 (accession no. MW898434) was identified by phenotypic and molecular methods as the best degrading strain in the base mineral medium contained AMX or AMC. S. maltophilia strain DF1 was capable of removing 88.7% (w/v) of 43 ppm AMX and nearly 100% (w/v) of 15.2 ppm clavulanic acid after 72 h, which was measured by UV spectrophotometry and HPLC analysis. The maximum antibiotic biodegradation for S. maltophilia DF1 strain by one factor at a time was obtained after 72 h, without any additional carbon source, at 150 rpm shaking, the inoculum size of 5% (v/v), pH 7, and temperature 30 °C. According to the one-way ANOVA, the pH was affected on the AMX and AMC biodegradation. Optimal condition AMX and AMC biodegradation were determined by response surface method (RSM) with Design Expert12 software for three factors included inoculum level (1, 3, 5% (v/v)), pH (6.5, 7.25, and 8), and incubation time (40, 55, 70 h). Optimum degradation of AMC predicted by RSM at pH 7.12, inoculum level 4.78% (v/v), and 60.19 h. According to the results of this study, microbial degradation of AMX and AMC by S. maltophilia DF1 is a suitable strategy for the elimination of these micropollutants from aquatic media in aerobic conditions. Graphical abstract: (Figure presented.) © The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University 2024.
Abdulkhani, A.,
Khorasani Z.,
Hamzeh Y.,
Momenbek, F.,
zadeh Z.E. Biomass Conversion and Biorefinery (21906815)(7)
Black liquor is the by-product of the pulping process where the lignin, hemicellulose, and extractive materials are separated from wood to produce paper pulp. As one of the primary lignin sources, black liquor is considered an important energy source from biomass to produce biofuels and value-added chemicals. However, soda alkaline lignin has limited industrial applications due to its insolubility in water and lack of reactivity. Therefore, chemical modification is essential to enhance its industrial applications. In this study, alkali lignin from bagasse was modified through sulfonation, sulfomethylation, and amination processes using different reaction conditions. The structural analysis of obtained products was investigated by FTIR and 1H-NMR. The molecular weight distribution and thermal stability of the water-soluble products were analyzed using gel permeation chromatography (GPC) and thermogravimetric analysis (TGA), respectively. The elemental analysis was used to measure the elements (CHNSO) of the obtained water-soluble derivatives. The chemical structure analysis of the samples with FTIR and 1HNMR confirmed the modification processes. The results indicate that modification led to increased water solubility and a decrease in the precipitation pH of lignin samples, due to the introduction of sulfonate and amin functunal groups on lignin. In addition, the molecular weight and thermal stability of modified lignins were increased due to the presence of sulfonate and amine groups compared to unmodified lignin. Graphical abstract: (Figure presented.). © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022.
Separation and Purification Technology (13835866)
An extraction-electrooxidation (E-EODS) system is introduced for the removal of dibenzothiophene (DBT) from model fuel (DBT in n-hexane). The process is run in an electrochemical cell as a batch reactor, where, the model fuel is in contact with an appropriate immiscible polar solvent composed of acetonitrile and water (MeCN-water, 90:10% v/v) that serves as both the extraction solvent and electrochemical medium. The electrochemical oxidation of DBT, which is extracted into the MeCN-water phase, enhances the continuous removal of DBT from the model fuel phase. The effects of the composition of the extraction solvent, applied potential and the process time on DBT removal efficiency are assessed. The results indicate that with the selection of the MeCN-water, 90:10 v/v in a 1:1 ratio respect to the model fuel, this extraction method yields about 100% extraction efficiency within 5 h, at 25 °C at 2.9 V and atmospheric pressure as determined by HPLC technique. Cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) techniques are applied to identify the electrochemical oxidation products of DBT. The electrochemical oxidation-derived extraction process through this method is innovative and feasible for deep desulfurization of liquid fossil fuels. © 2021
Nasrollahzadeh, M.,
Bidgoli N.S.S.,
Shafiei N.,
Momenbek, F. International Journal of Biological Macromolecules (01418130)
This study is aimed at the investigation of the preparation of sulfated lignin (SL) as a Bronsted acid catalyst for the preparation of 5-hydroxymethylfurfural (5-HMF). SL was characterized by different methods including FT-IR, FESEM, XRD, and EDS analyses. It shows promising results after 60 min of reaction at 140 °C, reaching 100% conversion of fructose precursor and 99% yield of 5-HMF, with a fructose: catalyst mass ratio of 10:6. © 2021 Elsevier B.V.
Journal Of Biological Inorganic Chemistry (09498257)23(2)pp. 181-192
The interaction of three complexes [Zn(II), Cu(II), and V(IV)] derived from an asymmetric bidentate Schiff-base ligand with DNA and HSA was studied using fluorescence quenching, UV–Vis spectroscopy, viscosity measurements, and computational methods [molecular docking and our Own N-layered Integrated molecular Orbital and molecular Mechanics (ONIOM)]. The obtained results revealed that the DNA and HSA affinities for binding of the synthesized compounds follow as V(IV) > Zn(II) > Cu(II) and Zn(II) > V(IV) > Cu(II), respectively. The distance between these compounds and HSA was obtained based on the Förster’s theory of non-radiative energy transfer. Furthermore, computational molecular docking was carried out to investigate the DNA- and HSA-binding pose of the compounds. Molecular docking calculations showed that H-bond, hydrophobic, and π-cation interactions have dominant role in stability of the compound–HSA complexes. ONIOM method was utilized to investigate the HSA binding of the compounds more precisely in which molecular-mechanics method (UFF) and semi-empirical method (PM6) were selected for the low layer and the high layer, respectively. The results show that the structural parameters of the compounds changed along with binding, indicating the strong interaction between the compounds with HSA and DNA. Viscosity measurements as well as computational docking data suggest that all metal complexes interact with DNA, presumably by groove-binding mechanism. © 2017, SBIC.
Electroanalysis (15214109)29(1)pp. 272-279
A simple, stable and recoverable sensor is developed based on selective and covalent immobilization of dopamine (DA) on the gold (Au) electrode modified by mercaptopropionic acid (MPA) self-assembled monolayers and then, activated with 1-ethyl-3(3-(dimethylamino)propyl)-carbodiimide hydrochloride (EDC)/n-hydroxysuccinimide (NHS) activators. Fabrication steps and analytical application of this modified electrode toward quantitative determination of DA in the presence of ascorbic and uric acids are verified by cyclic and differential pulse voltammetry (CV and DPV) methods in the absence of any redox probe. The oxidation peak current of adsorbed DA changed linearly with the concentration of DA in the range of 0.5 to 600.0 μM with a detection limit of 0.064 μM, and the RSDs varied from 1.4 to 3.5 % for n=3 at each point. Finally, the fabricated sensor is used successfully for electroanalytical determination of DA in human blood plasma and pharmaceutical injection real samples. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Biotechnology Letters (15736776)38(3)pp. 503-508
Objectives: To engineer the yeast Saccharomyces cerevisiae for the heterologous production of linalool. Results: Expression of linalool synthase gene from Lavandula angustifolia enabled heterologous production of linalool in S. cerevisiae. Downregulation of ERG9 gene, that encodes squalene synthase, by replacing its native promoter with the repressible MET3 promoter in the presence of methionine resulted in accumulation of 78 µg linalool l−1 in the culture medium. This was more than twice that produced by the control strain. The highest linalool titer was obtained by combined repression of ERG9 and overexpression of tHMG1. The yeast strain harboring both modifications produced 95 μg linalool l−1. Conclusions: Although overexpression of tHMG1 and downregulation of ERG9 enhanced linalool titers threefold in the engineered yeast strain, alleviating linalool toxicity is necessary for further improvement of linalool biosynthesis in yeast. © 2015, Springer Science+Business Media Dordrecht.
Journal of AOAC International (10603271)(2)
Methyl silane coated Fe3O4 magnetic nanoparticles were used for simultaneous extraction of the fat-soluble vitamins (FSVs). The amounts of extracted vitamins were determined by HPLC. The synthesized Fe3O4 nanoparticles were coated with silica and then modified with trimethoxymethylsilane (TMMS). The prepared particles were characterized by different methods. The best amounts of silica and TMMS in sorbent synthesis were 1.2 and 0.5 mL, respectively. The optimum pH values for the sample solution and washing buffer were 5 and 3, respectively. Application of 100 mg sorbent, 700 μL tetrahydrofuran, 5-fold dilution of the sample solution, and 1 min for sorption and desorption times were among the best conditions. At the optimum conditions, the calibration plots for each vitamin were obtained with good linearity (R2>0.9992) and suitable linear ranges. This method has a low LOD (<76.1 μg/mL), acceptable repeatability (RSD <5.63%) and reproducibility (RSD <4.71%), and good accuracy (recovery >90.3%). Preconcentration of low concentrations of vitamin D3 was performed, and results showed 3.7 times greater sensitivity after preconcentration. Finally, the amounts of the FSVs in pharmaceutical formulations were determined using the proposed method, and results showed good agreement with those reported by manufacturers.
Teimouri A.,
Mazaheri M.,
Chermahini A.N.,
Salavati, H.,
Momenbek, F. Journal of the Taiwan Institute of Chemical Engineers (18761070)
An efficient process for the conversion of glucose into 5-hydroxymethylfurfural (HMF) was studied in various solvents. Nano-POM/nano-ZrO2/nano-γ-Al2O3 catalysts were prepared and characterized by N2 physical adsorption, FTIR, X-ray diffraction and scanning electron microscopic techniques. The reaction time, reaction temperature and catalyst reuse cycle toward the reaction performance were investigated in detail. An HMF yield of 60.1% was achieved at 190 °C for 4 h. © 2014 Taiwan Institute of Chemical Engineers.
Journal of Liquid Chromatography and Related Technologies (10826076)(14)
In an effort to reduce the total amount of organic solvent required for the elution of fat-soluble vitamins (FSVs) in reversed-phase liquid chromatography separation, a systematic approach was developed using a mixture of methanol, water, and an alkanol as the mobile phase. In the optimization procedure, a five-parameter retention model was developed and the statistical evaluation of model, revealed that the variations of retention times of each vitamins caused by addition of alkanols to the mobile phase were predicted with an average relative deviation of 1.83%. For this model, all the and values for all vitamins were higher than 0.9839 and 0.9798, respectively, and lack of fit (LOF) values were not statistically significant. A mobile phase containing methanol/octanol/water (86:9:5) was proposed as the optimum mobile phase composition using grid search method and a good agreement was observed between predicted and experimental response values (relative error =-0.734%). Using this optimum condition, the simultaneous separation of six FSVs was achieved in 9.94 min. The results showed an improvement in the separation of FSVs and in reduction of the total amount of organic solvent used for separation with addition of low amount of alkanols as additive to the mobile phase. © 2015 Taylor & Francis Group, LLC.
Analytical And Bioanalytical Chemistry Research (2383093X)(2)
In this project, eggshell membrane was used as a solid phase extraction sorbent for extraction of morphine followed by HPLC analysis. At first, raw eggshell membrane was used and then, because of low adsorption of morphine on untreated eggshell membrane ( < 70%), modification of eggshell membrane surface was carried out using different surfactants and amines. The amine modified eggshells characterized by Furrier transform infrared spectroscopy and UV-Vis diffuse reflectance spectroscopy resulted in better adsorption of morphine. The effects of different factors on extraction efficiencies were investigated. Based on experimental results 20 ml of glutaraldehyde (35% V/V) and 2 mmoles of normal hexane amine have been chosen as the best condition for chemical modification. The optimum pH values for sample solution and washing buffer were 8. Application of 300.0 mg sorbent, 6 ml methanol as desorbing solvent, 0.5 ml of 5 mg l-1 morphine sample solution and 6 min for sorption and desorption times were among the best conditions for morphine preconcentration. At the optimum conditions, the calibration plot of morphine was obtained with good linearity (R2 = 0.9990) and using this plot, figures of merit of the proposed method were evaluated. The proposed method presents suitable working linear ranges (0.5-10, mg l-1), good limit of detection (0.095 mg l-1), acceptable repeatability (%RSD ≤ 4.50) and good accuracy (recovery = 101.6%). Finally, the amount of spiked morphine to saliva as a real sample was determined using this method.
Amin, M.M.,
Hatamipour, M.S.,
Momenbek, F.,
Nourmoradi, H.,
Farhadkhani, M.,
Mohammadi-moghadam, F. Scientific World Journal (23566140)2014
The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater. © 2014 Mohammad Mehdi Amin et al.
Mohammadi-moghadam, F.,
Amin, M.M.,
Khiadani, M.,
Momenbek, F.,
Nourmoradi, H.,
Hatamipour, M.S. Journal Of Environmental And Public Health (16879805)2013
The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR) as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R) isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants. © 2013 Fazel Mohammadi-Moghadam et al.
Ashengroph, M.,
Nahvi i., I.,
Zarkesh-esfahani, H.,
Momenbek, F. Applied Biochemistry and Biotechnology (15590291)(1)
To screen strains of halotolerant or halophile bacteria which are able to convert isoeugenol to vanillin, 36 different strains of bacteria isolated from the salty environments in Iran were investigated. During growth on isoeugenol, a moderately halotolerant Gram-negative coccobacil showed capability of converting isoeugenol to vanillin. Based on morphological, physiological, and phylogenetic studies, strain CSW4 was classified as a bacterium belonging to the genus Psychrobacter. The bioconversion products were confirmed by thin-layer chromatography, high-performance liquid chromatography, and spectral data obtained from UV/Vis spectroscopy, FTIR, and mass-spectroscopy. Using growing cells, vanillin reached its maximum level of 88.18 mg L -1 after 24 h of reaction time in the presence of 1 g L -1 isoeugenol, resulting in a molar yield of 10.2%. The use of resting cells led to the optimal yield of vanillin (16.4%) which was obtained after 18-h reaction using 1 g L -1 isoeugenol and 3.1 g of dry weight of cells per liter harvested at the end of the exponential growth phase. To improve vanillin yield, the effect of substrate concentration on vanillin production under resting cells conditions was also investigated. Using 10 g L -1 isoeugenol, the maximal vanillin concentration (1.28 g L -1) was achieved after a 48-h reaction, without further optimization. The present study brings the first evidence for biotransformation of isoeugenol to vanillin in the genus Psychrobacter. © 2011 Springer Science+Business Media, LLC.
Ashengroph, M.,
Nahvi i., I.,
Zarkesh-esfahani, H.,
Momenbek, F. Annals of Microbiology (18692044)(2)
There is a growing interest in exploiting microbial bioconversions for the production of high value-added products such as vanillin and vanillic acid. We conducted this study to screen strains of bacteria which are able to degrade ferulic acid, and to evaluate the possibility of forming vanillic acid via conversion of ferulic acid under resting cell conditions. Twenty-seven different strains of bacteria were isolated from different samples which in turn were collected from a variety of sites in Iran and examined for bioconversion of ferulic acid into vanillic acid by thinlayer chromatography (TLC) and high-performance liquid chromatography (HPLC) analyses. Based on TLC and HPLC analyses, the strain SHL1 giving highest vanillic acid yield was selected and identified as Bacillus licheniformis (GenBank accession number HQ111516) based on morphological and physiochemical characteristics and its 16S rDNA gene sequence. In the presence of 1 g/l ferulic acid, vanillic acid reached amaximum value of 494 mg/l (molar yield of 60%) after 45 h of reaction time using resting cells of strain SHL1 without further optimization. The present study gives the first evidence for ferulic acid biotransformation by B. licheniformis. © Springer-Verlag and the University of Milan 2011.
Amin, M.M.,
Faraji M.,
Momenbek, F.,
Hasanzadeh A.,
Sadani M. International Journal of Environmental Health Engineering (22779183)(1)
Aims: The aim of this study is to determine the PCE biodegradation potential in an Anaerobic Migrating Blanket Reactor (AMBR) that has not been used so far for the bioremediation of this compound, in high concentration, and to evaluate the system performance. Materials and Methods: This study was an Experimental Interventional study that was done from April 2010 to March 2011, in the Isfahan University of Medical Sciences. The AMBR was used in a type of laboratory scale, with a volume of 10 L, which was divided into four compartments, for the biological degradation of PCE in a synthetic substrate. The startup was done using anaerobic digested sewage sludge. The performance of the reactor was evaluated during four periods, with a PCE loading rate of 3.75 until 75 mg PCE/L.d. The hydraulic retention time (HRT) was 32 hours. Results: Optimum chemical oxygen demand (COD) removal efficiency was obtained, 98%, with an organic loading rate (OLR) equal to 3.1 g COD/L.d. For PCE removal, the optimum efficiency was observed to be 99.8%, with a PCE loading rate equal to 37.5 mg PCE/L.d. The average COD and PCE removal rates for the whole activity period of the reactor were 91.4 and 99.5%, respectively; 1.1 ± 0.7% from the influent PCE was adsorbed on the biomass and 20% was found in the headspace. Conclusions: The AMBR reactor, which provides full-scale studies and uses real industrial wastewater polluted with PCE, is a simple, efficient, and reliable method for the treatment of PCE. © 2012 Medknow. All Rights Reserved.
Ashengroph, M.,
Nahvi i., I.,
Zarkesh-esfahani, H.,
Momenbek, F. Current Microbiology (14320991)(3)
Candida galli strain PGO6 isolated from oil-contaminated water is the first isolated yeast strain which is capable to form vanillin and vanillic acid during isoeugenol biotransformation. The products were confirmed by thin-layer chromatography (TLC), changes in the UV absorption pattern and high-performance liquid chromatography (HPLC). The phenotypic and physiochemical characteristics as well as molecular phylogenetic analysis based on amplification the ITS1-5.8S-ITS2 rDNA regions indicated the isolated strain PGO6 was identified as C. galli (GenBank accession number HM641231). Resting cells of C. galli PGO6 from the late-exponential of growth phase were used as biocatalysts for the biotransformation of isoeugenol. The optimal molar conversion of vanillin (48%) and vanillic acid (19%) was obtained after a 30 h incubation using 0.1% (v/v) of isoeugenol and 6 mg of dry weight of cells per ml without further optimization. Under these conditions, the total amount of vanillin and vanillic acid was 583 mg l-1. Further biotransformation was carried out using 0.5% (v/v) of isoeugenol under the resting cells conditions, yielding a vanillin concentration of 1.12 g l-1 (molar yield 25.7%) after 60 h incubation. This study brings the first evidence for biotransformation of isoeugenol to vanillin and vanillic acid by a yeast strain. © 2010 Springer Science+Business Media, LLC.
Ashengroph, M.,
Nahvi i., I.,
Zarkesh-esfahani, H.,
Momenbek, F. New Biotechnology (18764347)(6)
In this study a novel strain was isolated with the capability to grow on eugenol as a source of carbon and energy. This strain was identified as Pseudomonas resinovorans (GenBank accession no. HQ198585) based on phenotypic characterization and phylogenetic analysis of 16S rDNA gene. The intermediates coniferyl alcohol, coniferyl aldehyde, ferulic acid, vanillin and vanillic acid were detected in the culture supernatant during eugenol biotransformation with this strain. The products were confirmed by thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and spectral data achieved from UV-vis, FTIR and mass spectroscopy. Using eugenol as substrate and resting cells of P. resinovorans SPR1, which were harvested at the end of the exponential growth phase, without further optimization 0.24. g/L vanillin (molar yield of 10%) and 1.1. g/L vanillic acid (molar yield of 44%) were produced after 30. h and 60. h biotransformation, respectively. The current work gives the first evidence for the eugenol biotransformation by P. resinovorans. © 2011 Elsevier B.V.
Chermahini A.N.,
Teimouri A.,
Momenbek, F.,
Zarei A.,
Dalirnasab Z. Journal of Heterocyclic Chemistry (19435193)(4)
In this study, the possibility of 5-substituted 1-H-tetrazoles synthesis using clays as catalyst was investigated. The reaction of a series of aromatic nitriles with sodium azide was catalyzed by montmorillonite K-10 or kaolin clays in water or DMF as solvent. Conventional heating or ultrasonic irradiation was used to promote reaction. The amount of nitrile to sodium azide mole ratio, amount of catalyst, reaction time, and solvent type were optimized. The versatility of this method was checked by using various nitriles, which showed reasonable yields of tetrazole formation. It was found that using nitriles with electron-with-drawing groups result in both higher yields and lower reaction times. The catalysts could be reused several times without significant loss of their catalytic activity. Compared to conventional heating, ultrasonic irradiation reduced reaction times and increased catalyst activity. The present procedure is green and offers advantages, such as shorter reaction time, simple workup, and recovery and reusability of catalyst. © 2010 HeteroCorporation.
Ashengroph, M.,
Nahvi i., I.,
Zarkesh-esfahani, H.,
Momenbek, F. Biocatalysis and Biotransformation (10292446)(5-6)
The popular demand for natural food additives has resulted in a number of processes for producing natural vanillin. Although there are chemical procedures and plant sources for vanillin production, microbial bioconversions are being sought as a suitable 'natural' alternative. The present paper describes the conversion of isoeugenol to vanillin by a novel bacterial strain isolated from soil. The strain was identified as Pseudomonas sp. strain KOB10 based on morphological and physiochemical characteristics and its 16S rDNA gene sequence. We optimized medium composition for vanillin production using a Taguchi experimental design. Eight factors, i.e. isoeugenol, glycerol, tryptone, K2HPO4, KH2PO4, Cu2, Mg2 and Ca2 concentrations, were selected and experiments based on an orthogonal array layout of L18 (2 2 × 36) were performed. Analysis of the experimental data using the Taguchi method indicated that Cu2 and glycerol concentrations had the highest impact on isoeugenol conversion into vanillin at a substrate concentration of 0.9 g L-1. Under the optimized conditions, growing cells of Pseudomonas sp. strain KOB10 produced 0.153 g vanillin L-1 from 0.9 g isoeugenol L-1, with a molar yield of 18.3% after incubation for 48 h. To improve the vanillin yield, the effect of other bioconversion parameters including time of isoeugenol addition, initial isoeugenol concentration and conversion time was studied; the results showed a maximum concentration of 3.14 g vanillin L-1 after a total incubation time of 88 h with 15 g isoeugenol L-1, which corresponded to a molar yield of 22.5%. Further standardization and optimization for vanillin production was challenging. © 2010 Informa UK, Ltd.
Journal of Chromatography A (00219673)(24)
An environmentally benign and simple method has been proposed for separation and determination of fat-soluble vitamins using isocratic microemulsion liquid chromatography. Optimization of parameters affecting the separation selectivity and efficiency including surfactant concentration, percent of cosurfactant (1-butanol), and percent of organic oily solvent (diethyl ether), temperature and pH were performed simultaneously using genetic algorithm method. A new software package, MLR-GA, was developed for this purpose. The results indicated that 73.6mM sodium dodecyl sulfate, 13.64% (v/v) 1-butanol, 0.48% (v/v) diethyl ether, column temperature of 32.5°C and 0.02M phosphate buffer of pH 6.99 are the best conditions for separation of fat-soluble vitamins. At the optimized conditions, the calibration plots for the vitamins were obtained and detection limits (1.06-3.69μgmL-1), accuracy (recoveries>94.3), precision (RSD<3.96) and linearity (0.01-10mgmL-1) were estimated. Finally, the amount of vitamins in multivitamin syrup and a sample of fish oil capsule were determined. The results showed a good agreement with those reported by manufactures. © 2010 Elsevier B.V.
Darvishi F.,
Nahvi i., I.,
Zarkesh-esfahani, H.,
Momenbek, F. Journal of Biomedicine and Biotechnology (11107243)
The nonconventional yeast Yarrowia lipolytica degrades very efficiently hydrophobic substrates to produce organic acids, single-cell oil, lipases, and so forth. The aim of this study was to investigate the biochemical behavior and simultaneous production of valuable metabolites such as lipase, citric acid (CA), and single-cell protein (SCP) by Yarrowia lipolytica DSM 3286 grown on various plant oils as sole carbon source. Among tested plant oils, olive oil proved to be the best medium for lipase and CA production. The Y. lipolytica DSM 3286 produced 34.6 ± 0.1 U/mL of lipase and also CA and SCP as by-product on olive oil medium supplemented with yeast extract. Urea, as organic nitrogen, was the best nitrogen source for CA production. The results of this study suggest that the two biotechnologically valuable products, lipase and CA, could be produced simultaneously by this strain using renewable low-cost substrates such as plant oils in one procedure. Copyright © 2009 Farshad Darvishi et al.
Chermahini A.N.,
Ghaedi A.,
Teimouri A.,
Momenbek, F.,
Dabbagh H.A. Journal of Molecular Structure: THEOCHEM (01661280)(1-3)
In this study the density functional theory at B3LYP/6-31++G(d,p) level was employed to evaluate the hydrogen bonding between tetrazole dimers in the gas phase. Four cyclic dimers including one 1H-1H and three 2H-2H dimers were considered. The N...H-N hydrogen bonding which studied in the self assembled structures has been estimated from stabilization energies. The calculated hydrogen-bonding energies of various tetrazole dimers showed a cooperative interaction in the cyclic ones. It was found that 1H-1H dimers are more stable and introduction of an electron-releasing group (ERG) into the tetrazole rings resulted in the formation of more stable hydrogen bonding. Harmonic frequencies of monomers and dimers were calculated and it was found that change in the complexation vibrations is sensitive to the strength of the N...H-N hydrogen bondings. Natural population analysis was performed to predict electrostatic interactions in the cyclic H-bonded complexes. © 2008 Elsevier B.V. All rights reserved.
Acta Chromatographica (12332356)(16)
A micellar liquid chromatographic procedure is described for simultaneous determination of sugars previously derivatized with 4-aminobenzoic acid ethyl ester (4-ABEE). The optimized conditions, determined by use of the super-modified simplex method, were temperature 30°C, mobile phase containing 17.3 mM sodium dodecyl sulfate, 0.01 M phosphate buffer, pH 6.69, and 7.73% (v/v) ethanol, and UV detection at 307 nm. The 4-ABEE derivatives were separated in 10 min but a peak assigned to excess reagent appears at 13 min. Analytical data including linearity (r > 0.9987), limit of detection (35.47-81.74 μg mL-1), precision (RSD < 5.73%), and accuracy, measured by determination of recovery (>91%), support the usefulness of the proposed method for measuring sugars. When the proposed method was applied to the analysis of sugars in an infant formula and a sample of sorghum syrup the results were in good agreement with the content reported by manufacturer and with results obtained by refractive index detection.
Analytical and Bioanalytical Chemistry (16182642)(3)
In this study the possibility of derivatizing sugars using microwave irradiation was investigated. The amount of reagent, irradiation intensity, and derivatization time were optimized. In the derivatization of sugars with p-nitroaniline the reaction is complete within 5min at 600W when the p-nitroaniline-to-sugar and NaBH3CN-to-sugar mole ratios were above 1.4 and 3.1, respectively. A Doehlert design was used to optimize the mobile phase for separation of p-nitroaniline-labeled sugars; and the best separation was obtained by use of 0.01molL-1 acetate buffer at pH 4.40 containing 11.0% acetonitrile. Analysis using this method was highly sensitive and analysis time was short. Finally, a food sample was analyzed using the proposed method.
Journal of Pharmaceutical and Biomedical Analysis (07317085)(2)
A rapid method has been described for separation and determination of Vitamins A and E using micellar liquid chromatography (MLC). Influence of temperature of column and addition of organic modifiers on separation efficiency was investigated. A temperature of 30°C and 1-butanol modifier was selected. Optimization of the parameters affecting the separation including percent of organic modifier, pH of the mobile phase, concentration of surfactant, and flow rate of the mobile phase was performed simultaneously using the super-modified simplex (SMS) procedure. Results showed that 11.7% 1-butanol, 76.9 mM sodium dodecyl sulphate (SDS), pH of 6.73 and a flow rate of 1.35 ml min-1 are the best conditions for separation of these compounds. The analytical parameters including linearity, r > 0.9990; limit of detection 1.71 and 4.52 μg ml-1 for A and E, respectively; precision of the method, R.S.D. < 2.85%; and recovery, more than 90%, show that the method is useful for measuring these compounds in pharmaceutical preparations. © 2004 Elsevier B.V. All rights reserved.
Annali di Chimica (00034592)(11)
Separation of six vitamers of vitamin B6 was performed by RP- HPLC using micellar mobile phase, UV and electrochemical detection. Effect of temperature, type and amount of organic modifier in mobile phase on efficiency and asymmetry factor showed that, the appropriate conditions were temperature of 35°C and 3.0-5.0% (v/v) 1-butanol in mobile phase. Variations of selectivity factor versus 1-butanol concentration, pH of mobile phase, and SDS concentration was investigated and the following optimized conditions were selected for the separation: 3.0% (v/v) 1-butanol, pH=5.5 and 65 mM SDS in mobile phase. Electrochemical behavior of vitamers in optimized mobile phase was investigated using cyclic voltammetry, and potential of +1.2 V versus Ag/AgCl(Sat.) was chose as working potential. Finally, separation of B6 vitamers using UV detection at 254 nm and electrochemical detection at +1.2 V was compared.
Analytical and Bioanalytical Chemistry (16182642)(3)
A super-modified simplex (SMS) method has been used to optimize the mobile phase used for separation of seven water-soluble vitamins in multivitamin tablets by gradient micellar liquid chromatography (MLC) with ultraviolet (UV) detection at 254, 295, and 361 nm. Effect of column temperature and addition of organic modifier to the mobile phase on separation efficiency were investigated: the appropriate conditions used were a temperature of 35°C and 1-butanol modifier. The sodium dodecyl sulfate (SDS) concentration, pH, and 1-butanol% in the mobile phase were chosen for simultaneous optimization using the SMS method. The optimum mobile phase was found to be 16 mmol L-1 (mM) SDS, 0.02 M phosphate buffer, pH 3.6, and a gradient of 3.5-10% (v/v) butanol. The total analysis time for vitamins was 75 min. The analytical parameters including linearity (r>0.9970), limit of detection (0.12-50 μg mL-1), precision of method (relative standard deviation (RSD) <8.90%), and accuracy obtained by the recovery assay (88-103%) support the usefulness of the proposed method for the determination of the water-soluble vitamins. © Springer-Verlag 2004.
