The positive effect of the decreased NADPH-preferring activity of xylose reductase from Pichia stipitis on ethanol production using xylose-fermenting recombinant Saccharomyces cerevisiae.
We focused on the effects of a mutation of xylose reductase from Pichia stipitis (PsXR) on xylose-to-ethanol fermentation using recombinant Saccharomyces cerevisiae transformed with PsXR and PsXDH (xylitol dehydrogenase from P. stipitis) genes. Based on inherent NADH-preferring XR and several site-directed mutagenetic studies using other aldo-keto reductase enzymes, we designed several single PsXR mutants. K270R showing decreased NADPH-preferring activity without a change in NADH-preferring activity was found to be a potent mutant. Strain Y-K270R transformed with K270R PsXR and wild-type PsXDH showed a 31% decrease in unfavorable xylitol excretion with 5.1% increased ethanol production as compared to the control in the fermentation of 15 g l(-1) xylose and 5 g l(-1) glucose.
Watanabe
Seiya
S
Faculty of Engineering, Kyoto University, Kyoto, Japan.
Pack
Seung Pil
SP
Saleh
Ahmed Abu
AA
Annaluru
Narayana
N
Kodaki
Tsutomu
T
Makino
Keisuke
K
D000449:Aldehyde Reductase / Q000235:genetics* / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D016254:Mutagenesis, Insertional; D009249:NADP / Q000378:metabolism*; D010843:Pichia / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism*
D000431:Ethanol; D009249:NADP; D014994:Xylose; D000449:Aldehyde Reductase