THE EFFECTS OF PHOSPHORIC-ACID PRETREATMENT ON CONVERSION OF CELLULOSE TO ETHANOL AT 45-DEGREES-C USING THE THERMOTOLERANT YEAST KLUYVEROMYCES-MARXIANUS IMB3

Here we report on the effects of phosphoric acid pretreated cellulose as a substrate for ethanol production by K. marxianus IMB3 using simul taneous saccharification and fermentation systems at 45 degrees C. Wit h untreated, milled filter paper as substrate the maximum amount of et hanol produced was 25% of the maximum theoretical yield. After pre-tre atment with 100% phosphoric acid, the yield increased to 42% of the ma ximum theoretical yield. When untreated microcrystalline cellulose was used as the fermentation substrate, yields of ethanol as 45 degrees C amounted to 16% of the maximum theoretical yield whereas pretreatment of the substrate with phosphoric acid resulted in an increase in etha nol production to 69% of the maximum theoretical yield. This suggests that pretreatment of substrate with phosphoric acid would contribute t o a reduction in the amount of exogenous enzyme needed.