Xylose-to-xylitol bioconversion by Ca-alginate entrapped Candida guilliermondii cells in sugarcane bagasse hemicellulosic hydrolysate was carried out in erlenmeyer flasks using the repeated-batch mode of fermentation. The hydrolysate was supplemented or not with ammonium sulfate and/or rice bran extract at the beginning of each repeated batch. Altogether, six sets of three repeated-batches were...

D-Xylitol is found in low content as a natural constituent of many fruits and vegetables. It is a five-carbon sugar polyol and has been used as a food additive and sweetening agent to replace sucrose, especially for non-insulin dependent diabetics. It has multiple beneficial health effects, such as the prevention of dental caries, and acute otitis media. In industry, it has been produced by che...

The specific rates of growth, substrate utilization, and ethanol production as well as yields of biomass and ethanol production on xylose for the recombinant Zymomonas mobilis ZM4(pZB5) were shown to be much less than those on glucose or glucose-xylose mixtures. Typical fermentations with ZM4(pZB5) growing on glucose-xylose mixtures followed two-phase growth kinetics with the initial uptakes of...

The fermentation of xylose is essential for the bioconversion of lignocellulose to fuels and chemicals, but wild-type strains of Saccharomyces cerevisiae do not metabolize xylose, so researchers have engineered xylose metabolism in this yeast. Glucose transporters mediate xylose uptake, but no transporter specific for xylose has yet been identified. Over-expressing genes for aldose (xylose) red...

BACKGROUND The thermotolerant methylotrophic yeast Hansenula polymorpha is capable of alcoholic fermentation of xylose at elevated temperatures (45 - 48 degrees C). Such property of this yeast defines it as a good candidate for the development of an efficient process for simultaneous saccharification and fermentation. However, to be economically viable, the main characteristics of xylose fermen...

OBJECTIVE The present study analyzed xylitol concentrations in artificial saliva over time after application of varnishes containing 10% and 20% xylitol. MATERIAL AND METHODS Fifteen bovine enamel specimens (8x4 mm) were randomly allocated to 3 groups (n=5/group), according to the type of varnish used: 10% xylitol, 20% xylitol and no xylitol (control). After varnish application (4 mg), specim...

OBJECTIVE To compare the immediate effect of xylitol chewing gum and xylitol mouth rinse on mutans streptococci (MS) levels in the saliva of adults with systemic sclerosis (SSc). METHODS Thirteen female adults with SSc were assigned randomly to either the xylitol chewing gum or xylitol mouth rinse groups. Participants in the chewing gum group were given 2 pellets (2.12g) of commercial xylitol...

The expulsion mechanism of xylitol 5-phosphate in Streptococcus mutans ATCC 25175 was studied using resting cells incubated in the presence of 14C-xylitol. The expulsion appeared to be a two-step process: xylitol 5-phosphate was first hydrolyzed to xylitol and inorganic phosphate, and the xylitol was subsequently expelled from the cells. The dephosphorylation step appeared to be energy-requirin...

  Objective: Although the most useful method to reduce mechanical dental plaque is brushing and flossing, but due to the lack of adequate effectiveness achieved by these methods, the use of other methods such as replacing sweeteners, including Xylitol and Sorbitol with sucrose in products such as chewing gums have come into the focus of attention. This research was done aimed at examine the eff...

This study aimed to select a yeast strain that effectively utilises xylose produce xylitol from the vinasse of ethanol broth obtained fermentation sugarcane bagasse hydrolysate. Eleven strains xylose-fermenting yeasts were evaluated for their abilities utilise and xylitol. Two showed outstanding performance in semi-defined medium selected further testing with medium. Candida guilliermondii TIST...