Abstract: The sulfuric acid hydrolysates of corn cob fiber is an important raw material for xylitol production. But the hydrolysates contain furfural and phenolic compounds and others, which are toxic to microorginasims during subsequent fermentation. In this study, new microorganisms Candida tropicalis LF01 were isolated from soil. Adaptation and encapsulation were carried out to enhance the inhibitors resistance in corn cob hydrolysate. The results indicated that the isolated and encapsulated strains Candida tropicalis LF04 could ferment xylose to xylitol in condensed corn cob hydrolysate without any detoxification. 76% xylose was fermented after 88 h at pH5.5 with the aeration 0.15vvm , and xylitol produced more than 61.768 g/L. The xylitol yield rate is up to 0.83 g/g, much higher than that of both the parent strains and the only isolated strain. The results also demonstrated that yeast treated with this method has the potential to be applied to xylitol industrialp roduction.

Key words: xylitol, xylose, adaptation, encapsulation, fermentation, corn cob, hydrolysate, Candida tropicalis