Valorization of sugarcane bagasse for bioethanol production through simultaneous saccharification and fermentation: Optimization and kinetic studies

This study focuses on the valorization of sugarcane bagasse (SCB), which is a waste by-product from the sugar industry for ethanol production. A simultaneous saccharification and fermentation process was modelled and optimized. In addition, the kinetics of Saccharomyces cerevisiae cell growth and ethanol formation under the optimized conditions were assessed using the logistic and modified Gompertz models respectively. The response surface methodology (RSM) was used for the optimization with input parameters consisting of enzyme loading (20-100 U/g), temperature (30-50 degrees C) and yeast titre (1-5 times). A maximum bioethanol concentration of 4.88 g/L was observed under the optimal process conditions of 1 time (yeast titre), 100 U/g (enzyme loading) and 39 degrees C (temperature). The RSM model revealed that the enzyme loading parameter significantly affected bioethanol production. Kinetics of cell growth gave a maximum specific growth rate (mu(max)) of 0.15 h(-1) and a maximum cell biomass concentration (X-max) of 2.58 g/L. The modified Gompertz model showed a maximum bioethanol concentration (P-m) and maximum bioethanol production rate (r(p, m)) of 3.12 g/L and 0.29 g/L/h respectively. These findings demonstrated the potential of sugarcane waste valorization for biofuel production through SSF processes, and provided insights into process design for large scale operations.