Kinetic evaluation of biobutanol production by Clostridium Bejerincki using hydrolysate of pretreated lemongrass waste

Abstract

A novel approach on utilization of lemongrass waste for biobutanol production was studied Hydrolysate from pretreated lemongrass waste was employed as substrate for biobutanol production through Acetone-Butanol-Ethanol (ABE) fermentation using Clostridium beijerinckii SRI. Application of physico-chemical pretreatment method resulted in high yield of reducing sugar concentration at 57.3 g/L .Profiling indicated that pretreated lemongrass waste consisted of five types of major sugars namely glucose, galactose, arabinose, mannose and xylose. Glucose and mannose were detected as the major sugars at 20.7 g/L and 21.3 g/L respectively. Screening of external factors (pH. temperature and reducing sugar concentration) for biobutanol fermentation was performed using one- factor-at-a time approach. The optimum conditions for biobutanol production was determined at pH 5.5, temperature 35°C and initial reducing sugar concentration of 40 g/L. Kinetic evaluation was simultaneously performed giving γ p/x values of 0.0263 g/g, 0.018 g/g and 0.055 g/g. and Tp/. values of γ p/x 0.64 g/g 0.28 g/g and 0.38 g/g when the fermentation was controlled at pH 5.5, temperature 35*C and initial reducing sugar concentration of 40 g/L respectively.