SIMULTANEOUS DETOXIFICATION AND ENZYME-PRODUCTION OF HEMICELLULOSE HYDROLYSATES OBTAINED AFTER STEAM PRETREATMENT

In the process of making ethanol from lignocellulosic materials, compo unds inhibitory to microorganisms are generated during steam pretreatm ent of the wood. Water-soluble inhibitors and pentoses are liberated a nd washed from the cellulose structure which is further enzymatically hydrolyzed. To make the process economically feasible, rite pentoses h ave to be fermented to ethanol. A major drawback with the pentose-ferm enting organisms that have been suggested for this purpose is that the y do not tolerate an inhibitory environment and there fore, the pentos e stream has to be detoxified prior to fermentation. An alternative us e of the hemicellulose hydrolysate obtained after steam;pretreatment o f willow is to use it for. enzyme production by the cellulolytic fungu s Trichoderma reesei. The sugars in the pentose function are almost co mpletely utilized, and simultaneously the hemicellulose hydrolysate is detoxified and can be recirculated in rite process to minimize the ne ed for freshwater. (C) 1997 by Elsevier Science Inc.