production of several yeast products occur in presence of mixtures of monosaccharides. to study effect of xylose and glucose mixtures with system aeration and nitrogen source as the other two operative variables on xylitol production by pichia guilliermondii, the present work was defined. artificial neural network (ann) strategy was used to athematically show interplay between these three contr...

Sulfolobus acidocaldarius utilizes glucose and xylose as sole carbon sources, but its ability to metabolize these sugars simultaneously is not known. We report the absence of diauxie during growth of S. acidocaldarius on glucose and xylose as co-carbon sources. The presence of glucose did not repress xylose utilization. The organism utilized a mixture of 1 g/liter of each sugar simultaneously w...

3-Dehydroshikimic acid is a hydroaromatic precursor to chemicals ranging from L-phenylalanine to adipic acid. The concentration and yield of 3-dehydroshikimic acid microbially synthesized from various carbon sources has been examined under fed-batch fermentor conditions. Examined carbon sources included D-xylose, L-arabinose, and D-glucose. A mixture consisting of a 3:3:2 molar ratio of glucose...

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. ...

Prioritization of sugar consumption is a common theme in bacterial growth and a problem for complete utilization of five and six carbon sugars derived from lignocellulose. Growth studies show that Lactobacillus brevis simultaneously consumes numerous carbon sources and appears to lack normal hierarchical control of carbohydrate utilization. Analysis of several independent L. brevis isolates ind...

The influence of D-ribose as a cosubstrate on the uptake and metabolism of the non-growth substrate D-xylose by Saccharomyces cerevisiae ATCC 26602 was investigated. Xylose was taken up by means of low- and high-affinity glucose transport systems. In cells exposed for 2 days to a mixture of xylose and ribose, only the high-affinity system could be detected. Glucose strongly inhibited the transp...

BACKGROUND Xylose is a second most abundant sugar component of lignocellulose besides glucose. Efficient fermentation of xylose is important for the economics of biomass-based biorefineries. However, sugar mixtures are sequentially consumed in xylose co-fermentation with glucose due to carbon catabolite repression (CCR) in microorganisms. As xylose transmembrance transport is one of the steps r...

BACKGROUND Glycolic acid (GA) is a two-carbon hydroxyacid with applications in the cosmetic, textile, and medical industry. Microbial GA production from all sugars can be achieved by engineering the natural glyoxylate shunt. The synthetic (d)-xylulose-1 phosphate (X1P) pathway provides a complementary route to produce GA from (d)-xylose. The simultaneous operation of the X1P and glyoxylate path...

The hydrolysis of lignocellulosic biomass opens an array bioconversion possibilities for producing fuels and chemicals. Microbial fermentation is particularly suited to the conversion sugar-rich hydrolysates into biochemicals. Rhizopus oryzae ATCC 20344 was employed produce fumaric acid from glucose, xylose, a synthetic hydrolysate (glucose–xylose mixture) in batch continuous fermentations. A n...