73 results about "Xylitol dehydrogenase" 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.

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.

Disclosed herein are Xylitol dehydrogenase-inactivated and arabinose reductase-inhibited mutant of Candida tropicalis, a method of producing a high yield of xylitol using the same, and xylitol produced by the method. More specifically, disclosed are a method for producing a high yield of xylitol, in which a high concentration of xylose contained in a biomass hydrolyzate is converted to xylitol using xylitol dehydrogenase-inactivated mutant of Candida tropicalis, without controlling dissolved oxygen to a low level, as well as xylitol produced according to the method. Also disclosed are a xylitol production method, in which the production of byproduct arabitol, which is produced when using a biomass as a substrate and adversely affects the yield of xylitol, is significantly reduced through the use of Candida tropicalis mutant ara-89 (KCTC 11136bp) having an inhibited activity of arabinose reductase converting arabinose to arabitol, thus increasing xylitol productivity, as well as xylitol produced by the method.

A method for producing a strain of Saccharomyces cerevisiae with introduced genes coding for xylose reductase, xylitol dehydrogenase and xylulokinase and with improved ethanol production, improved xylose conversion and reduced xylitol production is described. The method comprises culturing the cells in a repetitive batch series in a medium at a xylose concentration of about 15-25 g / l and at a temperature of about 28-32° C., and thereafter lowering the xylose concentration in at least one step at a temperature of about 28-32° C. to obtain an increased selection pressure for improved xylose fermentation,improved ethanol production and reduced xylitol production, and continuing the culturing of the cells in said repetitive batch series. Further, strains of Saccharomyces cerevisiae obtained by the method according to the invention are described.