Kinetic study on hydrolysis of sweet sorghum (Sorghum bicolor (L.) Moench) stem dregs with cocktail enzymes in bioethanol production

Abstract

Sweet sorghum stem dregs have potential as an alternative raw material for bioethanol production due to its high sugar content. The purpose of this study is to examine the hydrolysis kinetics of sweet sorghum stem dregs with cocktail enzymes using several models, namely the Valjamae, Kopelman, and Gompertz models. The hydrolysis was carried out at a concentration of 1/16.7 g/mL, a temperature of 50°C, and at variations of time (0, 12, 24, 36, 48, 60 and 72 minutes). The cocktail enzyme used was Multifect CL, which contains endoglucanases, exoglucanases, and β-glucosidases and has the potential to convert lignocellulose. The reactor used is CSTR (Continuous Stirred-Tank Reactor). The study results indicated that the hydrolysis kinetics of the Valjamae and Kopelman models were very suitable. The value of reaction rate constant and exponential fractal for the Valjamae model are 0.077 L/hour and 0.434 and for the Kopelman model are 0.044 L/hour and 0.415. The hydrolysis kinetics for the Gompertz model is not suitable. These hydrolysis kinetic parameters can be utilized in the bioreactors planning that will be used in the preliminary design of the biomass-based bioethanol industry.