Production and characterization of B-glucosidase from Aspergillus niger fermentation: Application for organic fraction of municipal solid waste hydrolysis and methane enhancement. Biotechnology Progress

Abstract

The anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) is currently an attractive treatment process with energy production in the form of bio- gas. Hydrolysis is the rate-limiting step for the anaerobic digestion of solid wastes. Thus, in the present study fungal enzymatic pretreatment of OFMSW was applied to enhance biogas production. Two enzyme cocktails rich on B-glucosidase were pro- duced from submerged fermentation of Aspergillus niger on basal medium using OFMSW as carbon source and urea (Urea cocktail) and Ulva rigida as nitrogen source (Ulva cocktail). Ulva cocktail displayed an important effect on OFMSW solubilization. Therefore, an increase of reducing sugar concentration about 60% was obtained which was in correlation with chemical oxygen demand (COD) increase. The perfor- mance of enzymatic pretreatment on anaerobic digestion of OFMSW was studied by conducting biochemical methane potential tests. Results showed that the enzymatic pretreatment improved methane yield of OFMSW even at high solid concentration. High methane yield about 500 ml/g total volatile solid was obtained, which corre- sponds up to 68% enhancement over the control.