Escherichia coli contains a cold osmotic shock-releasable binding protein for D-XylOSe which has been purified and characterized. The D-xylose-binding protein has an apparent molecular weight of 37,000 as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino acid analysis. D-Xylose-binding protein has an apparent absolute specificity for D-XYlose and binds one molecule o...

BACKGROUND Engineering of Saccharomyces cerevisiae for the simultaneous utilization of hexose and pentose sugars is vital for cost-efficient cellulosic bioethanol production. This yeast lacks specific pentose transporters and depends on endogenous hexose transporters for low affinity pentose uptake. Consequently, engineered xylose-fermenting yeast strains first utilize D-glucose before D-xylose...

The heterologous expression of a highly functional xylose isomerase pathway in Saccharomyces cerevisiae would have significant advantages for ethanol yield, since the pathway bypasses cofactor requirements found in the traditionally used oxidoreductase pathways. However, nearly all reported xylose isomerase-based pathways in S. cerevisiae suffer from poor ethanol productivity, low xylose consum...

This study focused on elucidating metabolism of xylose in a Saccharomyces cerevisiae strain that overexpresses xylose reductase and xylitol dehydrogenase from Pichia stipitis, as well as the endogenous xylulokinase. The influence of xylose on overall metabolism was examined supplemented with low glucose levels with emphasis on two potential bottlenecks; cofactor requirements and xylose uptake. ...

Background The use of lignocellulosic biomass rather than fossil fuel is an environmental sustainable alternative for bioethanol production. However, fermentation of lignocellulosic hydrolysates by Saccharomyces cerevisiae is not viable since this yeast cannot ferment xylose naturally. Current, several studies are being developed to introduce a pathway that allows pentose fermentation by S. cer...

Lampen (1) observed that cell-free extracts of LactobaciZZus pentosus grown on D-xylose catalyzed the disappearance of n-xylose in the presence of ATP.’ The phosphate esters which accumulated were identified as a mixture of D-ribose 5-phosphate and D-ribulose 5-phosphate. Neither n-xylose 5-phosphate nor D-xylulose 5-phosphate was found in the reaction mixture. Mitsuhashi and Lampen (2) also de...

Spent sulfite pulping liquor (SSL) contains lignin, which is present as lignosulfonate, and hemicelluloses that are present as hydrolyzed carbohydrates. To reduce the biological oxygen demand of SSL associated with dissolved sugars, we studied the capacity of Pichia stipitis FPL-YS30 (xyl3Delta) to convert these sugars into useful products. FPL-YS30 produces a negligible amount of ethanol while...

In mammals, xylose is found as the first sugar residue of the tetrasaccharide GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser, initiating the formation of the glycosaminoglycans heparin/heparan sulfate and chondroitin/dermatan sulfate. It is also found in the trisaccharide Xylalpha1-3Xylalpha1-3Glcbeta1-O-Ser on epidermal growth factor repeats of proteins, such as Notch. UDP-xylose synthase (UXS)...

Xylose utilization is one key issue for the bioconversion of lignocelluloses. It is a promising approach to engineering heterologous pathway for xylose utilization in Saccharomyces cerevisiae. Here, we constructed a xylose-fermenting yeast SyBE001 through combinatorial fine-tuning the expression of XylA and endogenous XKS1. Additional overexpression of genes RKI1, RPE1, TKL1, and TAL1 in the no...

An enhanced, xylose-utilizing strain of Rhizopus arrhizus was successfully developed via modification using media with increasing concentrations of xylose. Xylose, a relatively cheap monosugar that can be easily obtained from corncobs, rice straw, and vinasse, was the sole carbon source used for both the seed culture phase and the fermentation process. After modification, this newly improved st...