Document Type : Research Paper
Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore.
Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
In this study, food wastes such as waste bread, savory, waste cakes, cafeteria waste, fruits, vegetables and potatoes were used as sole substrate for glucoamylase production by solid state fermentation. Response surface methodology was employed to optimize the fermentation conditions for improving the production of high activity enzyme. It was found that waste cake was the best substrate for glucoamylase production. Among all the parameters studied, glucoamylase activity was significantly affected by the initial pH and incubation time. The highest glucoamylase activity of 108.47 U/gds was achieved at initial pH of 7.9, moisture content of 69.6% wt., inoculum loading of 5.2×105 cells/gram substrate (gs) and incubation time of 6 d. The enzyme preparation could effectively digest 50% suspension of domestic food waste in 24 h with an almost complete saccharification using an enzyme dose of only 2U/g food waste at 60°C.