Medical and Biomedical Researches

A mathematical model of ethanol fermentation from cheese whey : II. Simulation and comparison with e

June 27th, 2008
A mathematical model of ethanol fermentation from cheese whey : II. Simulation and comparison with experimental data. A cybernetic model for microbial growth on mixed substrates, was used to simulate the anaerobic fermentation of cheese whey and multiple sugars in semisynthetic media byKluyveromyces marxianus CBS 397. ...

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A mathematical model of ethanol fermentation from cheese whey : I: Model development and parameter e

June 27th, 2008
A mathematical model of ethanol fermentation from cheese whey : I: Model development and parameter estimation. The cybernetic approach to modeling of microbial kinetics in a mixedsubstrate environment has been used in this work for the fermentative production of ethanol from cheese whey. In this system, ...

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Performance of coimmobilized yeast and amyloglucosidase in a fluidized bed reactor for fuel ethanol

June 27th, 2008
Performance of coimmobilized yeast and amyloglucosidase in a fluidized bed reactor for fuel ethanol production. The performance of coimmobilizedSaccharomyces cerevisiae and amyloglucosidase (AG) was evaluated in a fluidized-bed reactor. Soluble starch and yeast extracts were used as feed stocks. Conversion of soluble starch streams to ethanol ...

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Evaluation of PTMSP membranes in achieving enhanced ethanol removal from fermentations by pervaporat

June 27th, 2008
Evaluation of PTMSP membranes in achieving enhanced ethanol removal from fermentations by pervaporation. The use of membrane processes for the recovery of fermentation products has been gaining increased acceptance in recent years. Pervaporation has been studied in the past as a process for simultaneous fermentation and ...

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Biogas production fromJatropha curcas press-cake.

June 27th, 2008
Biogas production fromJatropha curcas press-cake. Seeds of the tropical plantJatropha curcas (purge nut, physic nut) are used for the production of oil. Several methods for oil extraction have been developed. In all processes, about 50% of the weight of the seeds remain as a press cake ...

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Enzyme-supported oil extraction fromJatropha curcas Seeds.

June 27th, 2008
Enzyme-supported oil extraction fromJatropha curcas Seeds. Jatropha curcas is a tropical plant widely distributed in arid areas. The seeds contain about 55% of oil, which is mainly used for the production of soap as a fuel and after transesterification as biodiesel. Various methods for recovering of ...

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Membrane-mediated extractive fermentation for lactic acid production from cellulosic biomass.

June 27th, 2008
Membrane-mediated extractive fermentation for lactic acid production from cellulosic biomass. Lactic acid production from cellulosic biomass by cellulase andLactobacillus delbrueckii was studied in a fermenter-extractor employing a microporous hollow fiber membrane (MHF). This bioreactor system was operated under a fed-batch mode with continuous removal of lactic ...

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Potassium acetate by fermentation withClostridium thermoaceticum.

June 27th, 2008
Potassium acetate by fermentation withClostridium thermoaceticum. Potassium acetate is currently made by reacting petroleum-based acetic acid with potassium hydroxide. An alternate process, anaerobic fermentation of dextrose withClostridium thermoaceticum, could be used and could possibly be cheaper. Growth characteristics and productivity of the fermentation were optimized to ...

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Lipase production byPenicillium restrictum in a bench-scale fermenter : Effect of carbon and nitroge

June 27th, 2008
Lipase production byPenicillium restrictum in a bench-scale fermenter : Effect of carbon and nitrogen nutrition, agitation, and aeration. A preliminary screening work selectedPenicillium restrictum as a promising micro-organism for lipase production. The physiological response of the fungus towards cell growth and enzyme production upon variable carbon ...

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The effect of pectinase on the bubble fractionation of invertase from alpha-amylase.

June 27th, 2008
The effect of pectinase on the bubble fractionation of invertase from alpha-amylase. Fermentation broth normally contains many extracellular enzymes of industrial interest. To separate such enzymes on-line could be useful in reducing the cost of recovery as well as in keeping their yield at a maximum ...

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Production of fumaric acid by immobilized rhizopus using rotary biofilm contactor.

June 27th, 2008
Production of fumaric acid by immobilized rhizopus using rotary biofilm contactor. Rotary biofilm contactor (RBC) is a reactor consisting of plastic discs that act as supports for micro-organisms. The discs are mounted on a horizontal shaft and placed in a medium-containing vessel. During nitrogen-rich growth phase, ...

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Measurement of the steady-state shear characteristics of filamentous suspensions using turbine, vane

June 27th, 2008
Measurement of the steady-state shear characteristics of filamentous suspensions using turbine, vane, and helical impellers. The impeller viscometer technique is frequently used to characterize the rheology of filamentous suspensions in order to avoid difficulties encountered with conventional instruments. This work presents the results of experiments conducted ...

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Effect of impeller geometry on gas-liquid mass transfer coefficients in filamentous suspensions.

June 27th, 2008
Effect of impeller geometry on gas-liquid mass transfer coefficients in filamentous suspensions. Volumetric gas-liquid mass transfer coefficients were measured in suspensions of cellulose fibers with concentrations ranging from 0 to 20 g/L. The mass transfer coefficients were measured using the dynamic method. Results are presented for ...

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Cellulose production based on hemicellulose hydrolysate from steam-pretreated willow.

June 27th, 2008
Cellulose production based on hemicellulose hydrolysate from steam-pretreated willow. The production cost of cellulolytic enzymes is a major contributor to the high cost of ethanol production from lignocellulosics using enzymatic hydrolysis. The aim of the present study was to investigate the cellulolytic enzyme production ofTrichoderma reesei ...

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Experimental data analysis : An algorithm for determining rates and smoothing data.

June 27th, 2008
Experimental data analysis : An algorithm for determining rates and smoothing data. Reaction rate determination from experimental data is generally an essential part of evaluating enzyme or microorganism growth kinetics and the effects on them. Commonly used methods include forward, centered, or backward finite difference equations ...

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Acetobacter cellulosic biofilms search for new modulators of cellulogenesis and native membrane trea

June 27th, 2008
Acetobacter cellulosic biofilms search for new modulators of cellulogenesis and native membrane treatments. Since natural substances like pseudoxanthins exert a positive effect on the cellulogenic ability ofAcetobacter xylinum when producing cellulosic pellicles suitable for skin burn therapy, new defined and complex modulators were sought. Ca(2+) and ...

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Polysaccharide hydrolase folds diversity of structure and convergence of function.

June 27th, 2008
Polysaccharide hydrolase folds diversity of structure and convergence of function. Polysaccharide glycosyl hydrolases are a group of enzymes that hydrolyze the glycosidic bond between carbohydrates or between a carbohydrate and a noncarbohydrate moiety. Here we illustrate that traditional schemes for grouping enzymes, such as by substrate ...

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Astaxanthinogenesis in the yeastPhaffia rhodozyma : Optimization of low-cost culture media and yeast

June 27th, 2008
Astaxanthinogenesis in the yeastPhaffia rhodozyma : Optimization of low-cost culture media and yeast cell-wall lysis. Astaxanthin is a diketo-dihydroxy-carotenoid produced byPhaffia rhodozyma, a basidiomicetous yeast. A low-cost fermentation medium consisting of raw sugarcane juice and urea was developed to exploit the active sucrolytic/urelolytic enzyme apparatus inherent ...

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Corn steep liquor as a cost-effective nutrition adjunct in high-performanceZymomonas ethanol ferment

June 27th, 2008
Corn steep liquor as a cost-effective nutrition adjunct in high-performanceZymomonas ethanol fermentations. The ethanologenic bacteriumZymomonas mobilis has been demonstrated to possess several fermentation performance characteristics that are superior to yeast. In a recent survey conducted by the National Renewable Energy Laboratory (NREL),Zymomonas was selected as the ...

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Optimization of seed production for a simultaneous saccharification cofermentation biomass-to-ethano

June 27th, 2008
Optimization of seed production for a simultaneous saccharification cofermentation biomass-to-ethanol process using recombinantZymomonas. The five-carbon sugarD: -xylose is a major component of hemicellulose and accounts for roughly one-third of the carbohydrate content of many lignocellulosic materials. The efficient fermentation of xylose-rich hemicellulose hydrolyzates (prehydrolyzates) represents an ...

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Stabilization and reutilization ofBacillus megaterium glucose dehydrogenase by immobilization.

June 27th, 2008
Stabilization and reutilization ofBacillus megaterium glucose dehydrogenase by immobilization. Glucose dehydrogenase (GDH) fromBacillus megaterium was immobilized using aminopropyl controlled-pore silica (CPS, average pore sizes of 170 and 500 A) as a support and glutaraldehyde as a bifunctional crosslinking agent. The CPS-immobilized enzyme could be reused 12 ...

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Enhanced cofermentation of glucose and xylose by recombinantSaccharomyces yeast strains in batch and

June 27th, 2008
Enhanced cofermentation of glucose and xylose by recombinantSaccharomyces yeast strains in batch and continuous operating modes. Agricultural residues, such as grain by-products, are rich in the hydrolyzable carbohydrate polymers hemicellulose and cellulose; hence, they represent a readily available source of the fermentable sugars xylose and glucose. ...

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Fermentation of biomass-derived glucuronic acid bypet expressing recombinants ofE. coli B.

June 27th, 2008
Fermentation of biomass-derived glucuronic acid bypet expressing recombinants ofE. coli B. The economics of large-scale production of fuel ethanol from biomass and wastes requires the efficient utilization of all the sugars derived from the hydrolysis of the heteropolymeric hemicellulose component of lignocellulosic feedstocks. Glucuronic and 4-0-methyl-glucuronic ...

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Production of alpha-terpineol fromEscherichia coli cells expressing thermostable limonene hydratase.

June 27th, 2008
Production of alpha-terpineol fromEscherichia coli cells expressing thermostable limonene hydratase. The genes encoding a thermostable limonene hydratase have been located on a cloned fragment inEscherichia coli conferring growth on limonene and production of the monoterpenes perillyl alcohol and alpha-terpineol. Whole cell bioconversion studies at elevated temperature ...

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Asparaginase II ofSaccharomyces cerevisiae : GLN3/JURE2 Regulation of a Periplasmic Enzyme.

June 27th, 2008
Asparaginase II ofSaccharomyces cerevisiae : GLN3/JURE2 Regulation of a Periplasmic Enzyme. The production of some extracellular enzymes is known to be negatively affected by readily metabolized nitrogen sources such as NH4+ although there is no consensus regarding the involved mechanisms. Asparaginase II is a periplasmic enzyme ...

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