(764a) Current Status and Prospects of Industrial Xylitol Production in China

Xylitol is an alternative sweetener that has many beneficial health properties including regulating insulin-independent metabolism in humans, preventing dental caries and a number of pediatric diseases. Based on these promising advantages, xylitol has been commercially developed as a valuable ingredient for use in food and pharmaceutical industries. In China, xylitol is mainly produced industrially by the reduction of xylose derived from hemicellulose hydrolysates of biomass materials in the presence of Raney nickel catalysts. Currently, xylitol market lies between 20,000 and 40,000 tons per year with an economic value ranging between 90 and 340 million dollars and the xylitol market is expect to increase by 15% per year. The mainly Chinese companies including FUTASTE, LONGLIVE and HUAKANG PHARMA can produce about 40,000 tons per year. While chemical synthesis of xylitol has some disadvantages including a high energy requirement, extensive purification steps, and a high cost of product. Accordingly, the biological production of xylitol has recently attracted much attention. Many efforts have been made for the biological conversion of xylitol using microorganisms from hemicellulosic hydrolyzate by Chinese scientists. It is noteworthy that the xylitol productivity of recombinant Escherichia coli (1.84 g l^-1 h^-1 and 143.8 g l^-1 yield) by our previous work and the xylitol productivity of recombinant Candida tropicalis (2.01 g l^-1 h^-1 and 75.1 g l^-1yield) by Dr. Yuan's group are the highest xylitol productivity rates among recombinant bacteria and fungi from hemicellulosic hydrolyzate, respectively. Further, the industrial bio-production of xylitol and arabinose using C.tropicalis by Thomson Biotech from xylose mother liquor has been reported. All of above processes have been studied in an effort to provide one that is high yielding and competitive with chemical processes.