Screening of yeasts for production of xylitol from D-xylose

Candida mogii ATCC 18364 was selected for a xylitol producer (Y-P/S=0.62 g/g) from 11 strains of D-xylose utilizing yeasts. Systematic kinetic studies are presented for growth and xylitol formation in synthetic medium using D-xylose as the carbon and energy source. Xylitol is produced from D-xylose under aerobic as well as oxygen-limiting conditions, but not in the absence of oxygen. Tt can be seen from the experimental results that the concentrations of D-xylose and dissolved oxygen have a strong influence on the yield and rate for product formation, A maximum product yield was obtained when initial D-xylose concentration and specific oxygen uptake rate were 53 g/l and 0.5 mmol O-2/g/h, respectively. Kinetic studies of D-xylose uptake, D-xylose reductase and xylitol dehydrogenase were performed to explain the complex regulatory properties of C. mogii during aerobic and oxygen-limited xylitol formation.