Bioethanol Production: Optimization of Pretreatment Condition of Sugarcane Bagasse

Interest in the bioconversion of renewable lignocellulosic biomass into biofuel as an alternative to petroleum is rising globally. This study investigated the optimum chemical pretreatment concentration for bioethanol production using sugarcane bagasse. The bagasse was ground and subjected to various concentration of chemical treatment which include Hydrothermal (Hot‐H 2 O), Hydrogen peroxide (H 2 O 2 ) , Tetraoxosulphate VI acid (H 2 SO 4 ), Ethanol‐Tetraoxosulphate VI acid (C 2 H 5 OH and H 2 SO 4 ) , Sodium hydroxide (NaOH) , and Combined Ethanol‐Sodium hydroxide (C 2 H 5 OH and NaOH). This was followed by enzymatic hydrolysis using crude enzyme extract of Tricoderma viride and Aspergillus niger prior to anaerobic production of ethanol by fermentation using Saccharomyces cerevisiae . Results showed that pre‐treatment significantly (p<0.05) altered the percentage weight loss and cellulose content of the bagasse in a concentration dependent manner compared to the untreated control. Cellulose content and reducing sugars were maximal with NaOH pre‐treatment concentration. Crude enzyme of T. viride and A. niger co‐culture released significant (p<0.05) reducing sugar. The various pre‐treatment resulted in varying amount of ethanol comparable to control with NaOH and C 2 H 5 OH‐NaOH‐H 2 O treated showing improved yield. In conclusion, the effectiveness of any chemical pretreatment method is concentration dependent and essential for the release of cellulose for hydrolysis to fermentable sugar. A mutual synergy of co‐culture of A. niger and T. viride which resulted in increased cellulase, endo‐glucanase and β‐glucosidase activities could further be explored in bioethanol production.