High concentration fermentation of pentose to ethanol

Fermentation of glucose-xylose mixture to ethanol with Pichia stipitis was investigated.High concentration fermentation conditions were optimized by changing culture medium and cultivation conditions.The results showed that the initial xylose concentration of 63.0 g/L was appropriate in 24 h and initial xylose concentration of 72.0 g/L was suitable in 36 h.It was optimal by adding 54 g/L glucose in 24 h.The concentration of ethanol was 32.9 g/L.Further it was optimal by adding 72.0 g/L glucose in 36 h.The concentration of ethanol was 36.9 g/L.It was fit for(NH4)2SO4 to fermentation of ethanol with xylose.The concentration of(NH4)2SO4 was 1.1 g/L.Rotate speed of swing bed remained at 90 r/min in the first 8 h,then at 150 r/min after 16 h.The concentration of ethanol reached 17.5 g/L.