Enhancement of biogas production from swine manure by a lignocellulolytic microbial consortium

Abstract

Anaerobic digestion of lignocellulosic wastes is limited by inefficient hydrolysis of recalcitrant substrates, leading to low biogas yield. In this study, the potential of a lignocellulolytic microbial consortium (LMC) for enhancing biogas production from fibre-rich swine manure (SM) was assessed. Biochemical methane potential assay showed that inoculation of structurally stable LMC to anaerobic digestion led to increase biogas production under mesophilic and thermophilic conditions. The greatest enhancement was observed at 37°C with a LMC/SM ratio of 1.5:1 mg VSS/g VS leading to biogas and methane yields of 355 and 180 ml/g VS(added) respectively, equivalent to 40% and 55% increases compared with the control. The LMC was shown to increase the efficiency of total solid, chemical oxygen demand removal and degradation of cellulose and hemicelluloses (1.87 and 1.65-fold, respectively). The LMC-supplemented process was stable over a 90 d biogas production period. This work demonstrates the potential of LMC for enhancing biogas from lignocellulosic wastes.

Keywords: Anaerobic digestion; Biogas; Lignocellulolytic microbial consortium; Methane; Swine manure.