Optimization of enzymatic hydrolysis of kitchen waste using response surface methodology (RSM) for reducing sugar production

Abstract

Kitchen waste is a promising lignocellulosic biomass for bioethanol production due to its abundant availability, low cost and high carbohydrates content that can be converted to fermentable sugars. An enzymatic hydrolysis combined with response surface methodology was developed for reducing sugar extraction from kitchen waste. Central composite design (CCD) was employed to optimize enzyme loading, substrate concentration and hydrolysis time for high extraction yields. The kitchen waste was hydrolyzed with a cellulolytic enzyme, Trichoderma viride at constant pH of 4.8, temperature of 50°C and agitation speed of 150 rpm. The results obtained were interpreted by analysis of variance and response surface methodology. The optimal enzymatic hydrolysis conditions were as follows: enzyme loading of 100 mg with substrate concentration of 29 % (w/v) and hydrolysis time of 72 hr. Under the optimal conditions, a reducing sugar yield of 94.5 g/L was achieved. A regression model was generated according to the experimental data. Upon statistical analysis, coefficient of determination (R2) obtained was 0.9040.