86 results about "Xylose Reductase" patented technology

The present invention relates to a method for preparing an ethanol producing, xylose utilizing strain of Saccharomyces cerevisiae comprising genes for overexpression of xylose reductase, xylitol dehydrogenase and xylulokinase, wherein in addition to said genes for production o phosphoacetyltransferase, and acetaldehyde dehydrogenase are introduced and optionally overexpressed.

Production of ethanol using a strain of xylose-utilizing Zymomonas with a genetic modification of the glucose-fructose oxidoreductase gene was found to be improved due to greatly reduced production of xylitol, a detrimental by-product of xylose metabolism synthesized during fermentation.

Described are recombinant yeast which ferment xylose to ethanol and which maintain their ability to do so when cultured for numerous generations in non-selective media. The preferred yeast contain multiple copies of integrated genes encoding xylose reductase, xylitol dehydrogenase, and xylulokinase fused to promoters which are non-glucose inhibited and which do not require xylose for induction. Also described are preferred methods for integrating multiple copies of exogenous DNA into host cells by transforming cells with replicative / integrative vectors, and then replicating the cells a number of times under selective pressure to promote retention of the vector in subsequent generations. The replicated vectors thus serve to integrate multiple copies of the exogenous DNA into the host cells throughout the replication / selection phase. Thereafter the selective pressure can be removed to promote loss of the vector in subsequent generations, leaving stable integrants of the exogenous DNA.

The present invention relates to a method for obtaining a recombinant yeast of Saccharomyces cerevisiae, which ferments lignocellulose raw materials to ethanol, including introducing DNA into a yeast so as to cause the yeast to have introduced genes encoding xylose reductase, xylitol dehydrogenase and xylulokinase.

A new xylose reductase encoding gene from Neurspora crassa was heterologously expressed in E. coli as a His-tag fusion protein and subsequently purified in high yield. This xylose reductase was shown to have a high turnover rate and catalytic efficiency, high stability at room temperature, broad pH profile, and a preference of NADPH over NADH. This enzyme is utilized in production of xylitol and other sugar alcohols such as sorbitol and also in the metabolic enhancement of organisms used for fermentation of plant biomass into ethanol.