ISOLATION AND IDENTIFICATION OF NATIVE XYLITOL PRODUCING YEAST STRAIN AND OPTIMIZATION OF MICROBIAL PRODUCTION

Background and Aim:Among Plyols, xylitol is the sweetest poly-alcohol and due to high thermal resistance, is used as a dietary and pharmaceutical supplement. Xylitol usually is produced by chemical reduction of xylose or hemicellulotic compounds rich in xylose. Bioconversion of xylose to xylitol through micro-organisms does not need toxic catalists, is somhow easy and environmentally safe and is high valued according to defects of chemical method.Methods:In this stdudy efforts were done to isolate yeast from soil samples, tree leaves, flowers and vegetables, then identification of native yeast with the highest xylitol production was done through PCR method. Xylitol was analysed using HPLC method. Optimization of xylitol production was done using experimental design called as Taguchi methodResults:The yeast, Rhodotorula glutinis had highest xylitol production equivalent to 12.5 g/L. The yeast in medium conditions as rpm 150, temperature 23º C, pH= 6 and incubation period 72h had highest production. Chemical conversion of xylose to xylitol is difficult; because the yield is low and product recovery need highly costed functions to separate themConclusion:. As a result, biological production of xylitol using microorganisms is highly regarded nowadays and isolation and optimization of xylitol production using yeasts has great importance.

Keywords:

xylitol , Taguchi method , HPLC , PCR method