A Single-Reactor System for Simultaneous Pretreatment and Fermentation of POME for Bioethanol Production

Abstract

The objective of this study was to develop an efficient method for enhancing the production of bioethanol in a single-reactor system (SRS) by implementing acid–base pretreatment and enzymatic hydrolysis techniques, thereby eliminating differentiation and removal processes. The aim was to establish a process for bioethanol synthesis using hydrolyzed palm oil mill effluent (POME) and a locally sourced cellulase enzyme. The pretreatment and enzymatic hydrolysis methods were successfully optimized, resulting in a maximum yield of reducing sugars of 26.6 g/L (53.14%). To achieve the highest bioethanol yield, fermentation was carried out using both the one-factor-at-a-time (OFAT) and face-centered central composite design (FCCCD) approaches. The OFAT approach was employed to obtain the maximum bioethanol production, which yielded 6.75% v/v of bioethanol from the hydrolyzed POME using the same bioreactor. In the case of the FCCCD process, the optimal conditions led to a bioethanol production of 7.64% v/v during the fermentation stage. Kinetic analyses of the bioethanol produced revealed a specific growth rate (μ) of 0.198 h−1 and a specific product formation rate (qp) of 0.239 h−1 after 3 days of fermentation. These findings highlight a promising strategy for efficient management of POME through the production of biofuels, which could contribute to the economic growth of the country.