Noppol Leksawasdi

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(R)-Phenylacetylcarbinol [(R)-PAC)] is the chiral precursor for the production of the pharmaceuticals ephedrine and pseudoephedrine. Reaction conditions were improved to achieve increased (R)-PAC levels in a simple batch biotransformation of benzaldehyde emulsions and pyruvate, using partially purified pyruvate decarboxylase (PDC) from the filamentous(More)
A model has been developed for the fermentation of mixtures of glucose and xylose by recombinant Zymomonas mobilis strain ZM4(pZB5), containing additional genes for xylose assimilation and metabolism. A two-substrate model based on substrate limitation, substrate inhibition, and product (ethanol) inhibition was evaluated, and experimental data was compared(More)
Cellulase-free xylanase production by thermophilic Streptomyces thermovulgaris TISTR1948 was cultivated in a basal medium with rice straw as sole source of carbon and as an inducible substrate. Variable medium components were selected in accordance with the Plackett-Burman experimental design. The optimization conditions of physical factors (pH and(More)
Initial rate and biotransformation studies were applied to refine and validate a mathematical model for enzymatic (R)-phenylacetylcarbinol (PAC) production from pyruvate and benzaldehyde using Candida utilis pyruvate decarboxylase (PDC). The rate of PAC formation was directly proportional to the enzyme activity level up to 5.0 U ml-1 carboligase.(More)
It is believed that high concentrations of sodium chloride (NaCl) suppress the biosynthesis of exopolysaccharide (EPS) in lactic acid bacteria (LAB). Nevertheless, overproduction of EPSs due to high salinity stress in solid state fermentation performed on an agar surface was demonstrated in this study using a response surface methodology via a central(More)
Microbial extracellular polymeric substances (EPS) are potential biosorbents for metal remediation and recovery. The Langmuir and Freundlich kinetics of Mn(II) binding by the EPS from a novel Mn(II) oxidising strain of Rhizobium etli were determined. Maximum manganese specific adsorptions (q max) decreased in the sequence: sulphate (62 mg Mn per g EPS) >(More)
Cassava starch was melt-blended with glycerol (70/30wt%/wt%) at 140°C to prepare thermoplastic starch (TPS). Chitosan (CTS) was premixed with starch and glycerol, in acidified water (lactic acid 2wt%), at 1, 5 and 10wt%/wt%. TPS/CTS was then melt-blended (160°C) with polyethylene-graft-maleic anhydride (PE-MAH). Phase determination and scanning electron(More)
Cheese whey contains a high organic content and causes serious problems if it is released into the environment when untreated. This study aimed to investigate the optimum condition of lactic acid production using the microaerobic sequencing batch reactor (microaerobic SBR) in a nonsterile system. The high production of lactic acid was achieved by(More)
The optimal culture condition for extracellular recombinant single chain variable fragment anti HIV-1 p17 protein (scFv anti-p17) production in Escherichia coli HB2151 was investigated by the sequential simplex optimization (SS) method. Five variable parameters were submitted in the fermentation process. The most favorable condition obtained from 19(More)
Two amylases, amylase I and amylase II from Bacillus subtilis strain FP-133, were purified to homogeneity and characterized. Their stabilities toward temperature, pH, and organic solvents, and their substrate specificities toward polysaccharides and oligosaccharides were similar. Under moderately high salt conditions, both amylases were more stable than(More)