Ethanol production from sugarcane bagasse by means of on-site produced and commercial enzymes; a comparative study

Abstract

In this study ethanol was produced without using expensive commercial enzymes from sugarcane bagasse. Alkali pretreatment was used to prepare biomass before enzymatic hydrolysis. The comparison between NaOH, KOH and Ca(OH)_2 revealed that NaOH has been more effective on bagasse structure. The required enzymes for biomass hydrolysis were produced by bagasse solid state fermentation using three fungi: Trichoderma longibrachiatum, T. reesei and Aspergillus niger. Results indicated enzyme solution produced by A. niger has functioned better than the other two in cellulose conversion during sole hydrolysis. Ethanol was produced by simultaneous saccharification and fermentation (SSF) with on-site prepared crude enzyme solutions and yeast Saccharomyces cerevisiae. Here, T. longibrachiatum had the best performance in ethanol production. To evaluate this procedure, SSF of pretreated bagasse applying Celluclast 1.5L by Novozymes was also investigated. The yield of ethanol production by commercial enzyme and T. longibrac hiatum enzyme solution were 81% and 52.5% respectively.