Ethanol fermentation with xylose and glucose mixtures and Pichia stipitis

Key words: 
• forest engineering /
• Pichia stipitis /
• xylose fermentation /
• glucose /
• ethanol

Abstract: Using vegetable fibre to ferment ethanol can relieve energy crunch and improve environment protection. Here batch and continuous fermentation of xylose and glucose mixtures with Pichia stipitis were studied to provide basis for industrialized fermentation of ethanol. P. stipitis was cultured in a single-stage reactor with a mixture of 10.0,20.0,30.0,40.0,50.0,60.0 g·L-1 glucose and 5.0,10.0,15.0,20.0,25.0,30.0,60.0 g·L-1 xylose. Results showed that with a residual glucose concentration of not more than 10.0 g·L-1 in a culture medium with batch fermentation,glucose and xylose could be fermented by P.stipitis synchronously. Then,for continuous ethanol fermentation,glucose had great effect on fermentation with xylose. When P. stipitis was cultured in a single-stage reactor with a mixture of 30.0 g·L-1 glucose and 15.0 g·L-1 xylose, at a dilution rate of 0.08 h-1,9.40% of the xylose was consumed,and the ethanol concentration was 12.55 g·L-1. However,when the dilution rate was 0.04 h-1,66.07% of the xylose was consumed,and the ethanol concentration was 16.93 g·L-1.