Abstract: Candida tropicalis cells were immobilized in Ca-alginate beads and used for xylitol production from corn cob hydrolysates.Optimum batch fermentation conditions were as follows:32℃;per liter nitrogen contains 2.2 g (bacto-yeast) extract and 3.7 g bacto-tryptone;initial pH value 6.0;volume ratio between gel beads of immobilized cells and hydrolysates 1:4;shaking speed was divided into two stages:210 r/min at 0-24 h,140 r/min at 24-72 h.In 10 repeated batches(30 days) fermentation,average xylitol yield was 73.7%.The immobilized cells have high density,steady fermentability and good resistance to inhibitors in the hydrolysates.Corn cob hydrolysates can be directly converted to xylitol without being decolored or ion-exchanged.This process can effectively reduce production costs,showing a broad prospects of applications.