Expression of XYL1 of Candida tropicalis in Pichia pastoris and Xylitol Fermentation by Immobilizing Cells / 中国生物工程杂志

XYL1 gene,which encodes xylose reductase with dual coenzyme activity from Candida tropicalis,was transformed into Pichia pastoris X-33 by expression vector pGAPZB.The recombination strain was immobilized in Ca-alginate beads and fermentation characterization is studied using corn cob hydrolysates.Fermentation conditions were as follow:initial pH value 6.0,30℃,initial cell concentration of 20%,the Liquid volume of 28%,rotation speed 130r/min.The average xylitol yield was 37.5% on the optimum condition.This result is expected to provide a new alternative method for producing xylitol on a large scale by bioconversion.