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 kinet ic studies are presented for growth and xylitol formation in synthetic medium using D-xylose as the carbon and energy source. Xylitol is pro duced from D-xylose under aerobic as well as oxygen-limiting condition s, but not in the absence of oxygen. Tt can be seen from the experimen tal results that the concentrations of D-xylose and dissolved oxygen h ave 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, res pectively. 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 form ation.