Effect of Xylose and Glucose on Xylitol Production by Candida parapsilosis

Candida parapsilosis에 의한 Xylitol 생산시 Xylose와 Glucose가 미치는 영향

  • Oh, Deok-Kun (Department of Food Science and Technology, Woosuk University) ;
  • Kim, Sang-Yong (Tong Yang Confectionery Co,. R&D Center)
  • 오덕근 (우석대학교 식품공학과) ;
  • 김상용 (동양제과(주) 기술연구소)
  • Published : 1996.12.30

Abstract

Effects of xylose and glucose on the xylitol production were investigated with Candida parapsilosis KFCC 10875. With increasing the ratio of glucose to xylose, xylitol production decreased but ethanol and glycerol production increased. The maximum concentrations of ethanol and glycerol were 21.5 g/l and 3.6 g/l, respectively, in a medium consisting of 10 g/l xylose and 40 g/l glucose. No xylitol was formed in the glucose medium without xylose since xylitol could not be produced from glucose alone. The inhibitory effect of ethanol, a major by-product, on xylitol production was also studied. As the added ethanol concentration was increased, xylitol production decreased. When cells were inoculated in a xylose medium after removing the by-product (ethanol), xylitol production was not inhibited. The concentrated cells grown on xylose or glucose were inoculated in a fermentor containing the xylose medium. The total activities $(specific{\;}activities{\times}\;cell\;concentration)$ of xylose reductase and xylitol dehydrogenase in concentrated cells grown on glucose were the same as those in a normal fermentation; the specific activities of the above enzymes in the cells grown on xylose were the same as those in a normal fermentation. It indicates that the xylitol productivity of concentrated cells grown on xylose could be increased with increasing the cell concentration. By using concentrated cells of 20 g/l grown on xylose, the final xylitol concentration of 40 g/l was obtained for 18 h fermentation from 50 g/l xylose.

Keywords

xylitol;xylose;glucose;Candida parapsilosis