Enzymatic hydrolysis of complex agrowastes by Bacillus cereus ARA-12 A sustainable approach for biofuel production

Abstract

Currently petroleum-based fossil fuels are the main source of the production of energy. The major issue is that all these resources are non-renewable. As the demand of fuel increases day by day, these non-renewable resources may deplete shortly and will not meet the supply criteria according to the requirements. To overcome this problem, the production of bioethanol using wastes biomass such as fruit peels, agricultural waste, municipal and kitchen waste etc. has gained considerable attention. As these agro-wastes mainly contain lignocellulosic biomass, lignocellulolytic bacterial cultures harness the full potential of these substances. In the present study, endoglucanase producing Bacillus cereus ARA-12 was isolated from soil samples. Fermentation parameters to produce endoglucanase were optimized. The optimum production of endoglucanase was achieved in the medium containing carboxymethyl cellulose (15g/L), yeast extract (30g/L), KH₂PO₄ (1g/L), K₂HPO₄ (1.45g/L), MgSO₄ (0.4g/L), CaCl₂ (0.05g/L) and FeSO₄ (0.00125g/L). The optimum temperature and pH of the medium were found to be 50°C and 8 respectively. The maximum enzyme production was achieved at agitation speed of 120 rpm after 20 hours of fermentation by using 5% inoculum. Maximum of 35.9 % bioethanol was produced by the action of endoglucanase enzyme on sugarcane bagasse whereas sweet potato, rice bran, banana peel, corn cob, potato peel and corn husk were also found to be potential raw material to produce second-generation biofuel.