Response Surface Optimization for Microwave-Assisted Alkaline Pretreatment of Plantain Pseudostem Biomass for Bioethanol Production

Abstract

Bioethanol is a better alternative to gasoline because its combustion releases little or no dangerous gases to the environment and it is produced from renewable feedstock. However, the availability of bioethanol at commercial level is limited by factors such as the recalcitrant nature of the feedstock as well as the cost of the hydrolytic enzyme. In this study, microwave-assisted alkaline pretreatment was optimized via Box-Behnken experimental Design in Design expert software version 11 to effectively remove lignin from plantain pseudostem. The structure of plantain pseudostem pretreated at optimal conditions were characterized using FTIR, XRD, and SEM. Statistical and regression analysis on the experimental outcomes revealed that the lignin removal follows 2FI model with R² value of 0.9601, adjusted R² values of 0.9361 and predicted R² value of 0.8516; the cellulose content follows 2FI with R² value of 0.9616, adjusted R² values of 0.9386 and predicted R² value of 0.9094; the hemicellulose content followed quadratic model with R² value of 0.9591, adjusted R2 values of 0.9065and predicted R² value of 0.8463. The high adequate precision values of cellulose (42.33), lignin removal (23.58) and hemicellulose (15.87) shows that the developed models are true representation of the experimental study. The XRD, FTIR and SEM results of the treated plantain demonstrated that microwaveassisted alkaline pretreatment is effective in removing the recalcitrant nature of lignin. This can be a relatively cheaper feedstock for the production of bioethanol.