Fermentation production of ethanol by Pichia stipitis NLP31.

Fermentation of Pichia stipitis NLP31 on three types of media composed of sugars of 45 g/L xylose or mixture sugars(glucose 30 g/L,xylose 15 g/L) in 3 batches were investigated.The results showed that the ethanol concentration were the highest values by(17.29±0.15) g/L and yield of(84.65±0.58)% on fermentation medium III.The production course showed that the fermentation time of mixture sugar reached its highest ethanol level by 12 h,which was 8 h less than the control time with xylose alone.The fermentability of Pichia stipitis NLP31 was hight on the fermentation medium with less expensive inorganic nitrogen source,thus reducing the cost of the fuel ethanol production.