| Low-cost bioethanol production using pretreated agro-industrial wastes as the substrate is one of the key answer for future energy demand. In this study, fungal isolates were screened for activities of multi non-starch hydrolyzing enzymes as well as raw-starch degrading amylase to produce single crude enzyme for pretreatment of cassava pulp, the solid waste of cassava starch industry. Primary screening of polygalacturonase and cellulase (CMC) activities of 30 BCC fungal isolates resulted in Mamihiosphaeria sp. PP 41, Aspergillus sp. KPFC 334, and A. niger TR 38 as selected potential isolates. Crude enzyme production was conducted under optimized media and culture condition for each isolate, which were cassava pulp + soybean + orange peel for Mamilliosphaeria sp. PP 41 and wheat bran + soybean + pectin for the rest two Aspergilus strains. All fermentations were conducted in submerged cultures. Enzymatic pretreatment of cassava pulp for 24 hours resulted in release of reducing sugars time-dependently, with the three selected BCC enzymes released the highest reducing sugars from the pulp (up to 80%) compared to commercial enzyme mixture, cellulase alone, and without enzymatic treatment. The use of the three selected BCC enzymes thus enabled skipping further starch hydrolysis steps and gave a chance for simultaneous hydrolysis and fermentation of cassava pulp to provide reducing sugar starter for ethanol production. |