ETHANOL-PRODUCTION FROM ENZYMATIC HYDROLYZATES OF CELLULOSIC FINES AND HEMICELLULOSE-RICH LIQUORS DERIVED FROM AQUEOUS STEAM FRACTIONATION OF FORAGES/

This study was aimed at evaluating perennial forages (timothy grass, a lfalfa, and reed canary grass) as substrates for ethanol production. T wo fractions, derived from the aqueous/steam fractionation of these pl ants, were used as carbon sources for ethanol production: (i) a soluti on containing water-soluble hemicelluloses and (ii) cellulosic fines r ecovered after a delignification step. Both fractions were enzymatical ly hydrolyzed. The hemicellulose-rich fraction was easily saccharified with 90% of theoretical yield. Cellulosic fines were saccharified at 60-70% of theoretical yield. Increasing the delignification of cellulo sic fines by alkaline peroxide treatment resulted in higher sugar yiel ds. The glucose-rich hydrolyzate from cellulosic fines was easily ferm ented to 80-90% of theoretical ethanol yield with Saccharomyces cerevi siae or Pachysolen tannophilus. The pentose-rich hydrolyzate from wate r-soluble hemicelluloses was fermented to only 20% of theoretical etha nol yield with Pachysolen tannophilus. A Lime treatment of the hemicel lulose-rich liquors improved cell growth but did not improve ethanol p roduction.