Optimized activated charcoal detoxification of acid-pretreated lignocellulosic substrate and assessment for bioethanol production

Abstract

This study optimized an activated charcoal (AC) detoxification method for the reduction of three different fermentation inhibitor compounds, while minimising the reducing sugar loss from acid-pretreated sorghum leaf (SL) wastes. Process optimization demonstrated a 98%, 88% and 37% removal efficiency for furfural, 5-hydroxymethylfurfural (HMF) and acetic acid respectively, with a 7% reducing sugar loss. Subsequently, the logistic and modified Gompertz models were used to comparatively evaluate the kinetics of Saccharomyces cerevisiae growth and ethanol production using the non-detoxified (NDF) and optimized detoxified (ODF) substrate. Yeast cell growth and bioethanol kinetic coefficients revealed that the ODF process was more effective than the NDF system. The experimental data generated from this study revealed that a suitable, cost-effective AC detoxification enhanced cell growth and bioethanol production efficiency. These findings pave the way for biomass pretreatment, detoxification and bioethanol process development using lignocellulosic wastes.

Keywords: Activated charcoal; Bioethanol; Detoxification; Inhibitor compounds; Optimization.