Optimation xilitol production with variation of sugar cane bagasse hemicellulose hydrolysate concentration by Candida tropicalis

Abstract

The aims of this research were to study the growth of C. tropicalis, the optimation of xilitol production and the efficiency of xilitol production by varying the concentration of sugar cane bagasse hemicellulose hydrolysate. The frame work of this research was bioconversion xilosa into xilitol by C. tropicalis influenced substrate concentration in production medium. By using different sugar cane bagasse hemicellulose hydrolysate concentration could be known the optimum sugar cane bagasse hemicellulose hydrolysate concentration on xilitol production by introducing C. tropicalis. The methods used in this experiment were as follow: sugar cane bagasse was hydrolyzed by H2SO4 0.035 M in autoclave at 121ï‚°C, 2 atm for 20 minutes. The liquid fraction was concentrated at 50ï‚°C using rotary evaporator. The hydrolysate was neutralized with Ca(OH)2 to a pH of 10 and then removed by centrifugation at 2000 rpm for 20 minutes. The hydrolysate was added with H2SO4 to a pH 6.5 and then removed by centrifugation at 2000 rpm for 20 minutes and sterilized by autoclaving at 121ï‚°C for 15 minutes. Sugar cane bagasse hemicellulose hydrolysate concentration was variated from 10%, 20%, and 30% and used as substrate in production medium. Bioconversion process by C. tropicalis lasted for 4 days. Parameters used in this experiment were biomass of C. tropicalis measured by hemacytometer, xilosa and xilitol concentration in the sugar cane bagasse hemicellulose hydrolysate and production medium was analyzed by High Performance Liquid Chromatographic (HPLC). The results showed that: the growth of C. tropicalis lasted for 4 days of cultivation increased in every variation of sugar cane hemicellulose hydrolysate concentration. The optimum xilitol production founded in production medium contained 20% sugar cane bagasse hemicellulose hydrolysate in the third days cultivation with xilitol production 10.258 g/l, yield 0.22 g/g and biomass of C. tropicalis 2.9 x 108 cell/ml; The optimum efficiency of xilitol production from sugar cane bagasse hemicellulose hydrolysate by C. tropicalis was 24.21% in 20% sugar cane bagasse hemicellulose hydrolysate in the third days cultivation.