Monday, May 4, 2009
11-26
Approach for pentitol production from acid-pretreated rice straw hydrolysate by an adapted Pichia stipitis
Chiung-Fang Huang, Wei-Hsi Chen, Wen-Heng Chen, and Jia-Baau Wang. Cellulosic Ethanol Program, Institute of Nuclear Energy Research, No. 1000, Wenhua Road, Jiaan Village, Longtan, Taoyuan, 32546, Taiwan
Pentitol has been applied widely in the food processing, nutrition and pharmaceutical industries. This study was aimed to develop pentitol production technology from lignocellulosic materials. The capability of production for pentitol such as xylitol and ribitol, was found in the xylose utilization by yeast Pichia stipitis, which has been through a prolonged adaptation on the acid-pretreated rice straw hydrolysate. Initial xylose concentration was proposed to greatly influence the pentitol production. In comparison to the case with initial xylose concentration of 2%, the production yields of xylitol and ribitol were individually increased 7.88 and 17.2 fold as initial xylose concentration was reached to 6 %. Furthermore, this adapted P. stipitis was also shown the ribitol yield of 5 % (percentage of g product per g consumed sugar) from fermentation of rice straw hydrolysate, which was prepared by twin-screw extruder before acid-catalyzed pretreatment. The mechanism for the production of xylitol and ribitol by adapted P. stipitis is needed to be elucidated. Transcriptomic and proteomic profiles analysis of this adapted P. stipitis are currently under investigations, and it is hopeful to shed some light on the metabolic pathway of the adapted P. stipitis.