A Comparison of Liquid Hot Water and NaOH Pretreatment on Anaerobic Digestion of Sugar Cane Bagasse for Biogas Production

Abstract

<abstract> <bold>Abstract.</bold> As a kind of fiber residual by-product after extraction of sugar cane juice, sugar cane bagasse is rich in soluble sugar, cellulose, hemicellulose and lignin, which could be a potential feedstock for biogas production via anaerobic digestion. Lignocellulose in sugar cane bagasse composed of cellulose, hemicelluloses and lignin, is extremely resistant to enzymatic digestion. Therefore, a pretreatment is usually required to disrupt the plant cell wall structure by breaking the linkage between cellulose, hemicelluloses, and lignin. In this study, batch experiments were undertaken with anaerobic digestion devices in lab condition at mesophilic temperature (35±1 °C). Liquid hot water (LHW) pretreatment (temperature was raised to 120 °C, 150 °C, 180 °C and maintained for 20 min) and NaOH pretreatment (amount of NaOH attributes 1%, 2%, 3% and 4% of bagasse fresh weight) were used for the pretreatment of sugar cane bagasse. Methane content were analyzed for comparing the effects of two different pretreatment methods. The results showed that after LHW pretreatment and NaOH pretreatment the gas yield of each pretreatment group increased significantly when compared with unpretreated group. NaOH pretreatment groups had a higher production of biogas than LHW pretreatment groups. The 3% concentration NaOH pretreatment had a higher result with 235.1 mL/g-VS gas production yield. These methods of pretreatment provided a feasible way for the disposal of waste residual sugar cane bagasse.