The fermentation mechanism of the simultaneous production of D-xylonic acid and xylitol from D-xylose by Pichia quercuum was studied by using a cell-free enzyme preparation. Nicotinamide adenine dinucleotide phosphate (NADP)-dependent D-xylose dehydrogenase activity and NADP-dependent D-xylose reductase activity were detected, and the oxido-reduction reaction of D-xylose was able to couple thro...

Xylitol has sweetening, anticariogenic and clinical properties that have attracted the attention of the food and pharmaceutical industries. The conversion of sugars from lignocellulosic biomass into xylitol by D-xylose-fermenting yeast represents an alternative to the chemical process for producing this polyol. A good source of D-xylose is sugarcane bagasse, which can be hydrolyzed with dilute ...

Xylitol dehydrogenase (XDH) was purified from the cytoplasmic fraction of Gluconobacter oxydans ATCC 621. The purified enzyme reduced D-xylulose to xylitol in the presence of NADH with an optimum pH of around 5.0. Based on the determined NH2-terminal amino acid sequence, the gene encoding xdh was cloned, and its identity was confirmed by expression in Escherichia coli. The xdh gene encodes a po...

Not only is having a dry mouth uncomfortable, but it also contributes to tooth decay and to cavities because people with dry mouth do not produce enough saliva, which has bacterial properties. Chewing xylitol gum is a convenient and unobtrusive way of addressing both of these issues. Xylitol gum simulates saliva production, which helps relieve symptoms in more minor cases of dry mouth. In addit...

In this study we used the yeast Candida guilliermondii FTI 20037 immobilized by entrapment in Ca-alginate beads (2.5-3 mm diameter) for xylitol production from concentrated sugarcane bagasse hemicellulosic hydrolysate in a repeated batch system. The fermentation runs were carried out in 125- and 250-ml Erlenmeyer flasks placed in an orbital shaker at 30 degrees C and 200 rpm during 72 h, keepin...

BACKGROUND Ethanolic fermentation of lignocellulosic biomass is a sustainable option for the production of bioethanol. This process would greatly benefit from recombinant Saccharomyces cerevisiae strains also able to ferment, besides the hexose sugar fraction, the pentose sugars, arabinose and xylose. Different pathways can be introduced in S. cerevisiae to provide arabinose and xylose utilisat...

As a rare sugar alcohol, L-arabitol can be used in food and can prevent extra fat deposits in the intestinal tract. Commercially, L-arabitol is prepared from pure L-arabinose by hydrogenation, which needs a high temperature and high pressure, leading to a high production cost for Larabitol. Therefore, this study describes a novel L-arabitol production method based on biological purification fro...

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...