Optimization of biomethane production from lignocellulosic biomass by a developed microbial consortium

Abstract

Biomethane production from lignocellulosic biomass via anaerobic digestion (AD) is a promising avenue for bioenergy. However, maximizing biomethane yield using developed microbial consortium (DMC) remains a complex challenge. This study aims to elucidate the comparative efficacy of a purposefully DMC under controlled conditions for AD of kallar grass (KG), rice husk (RH) and wheat residue (WR). The DMC encompasses Bacteroidetes, Firmicutes, Proteobacteria, Euryarchaeota, and Chloroflexi, with methanogens representing 14.6% of the community. Thorough physico-chemical characteristics and ultimate analyses provided comprehensive insights into compositions and bio-methane potentials prediction of biomasses. The digester revealed higher biomethane potentials (BMPs) with short lag phase and retention time and showed methane content of 61–64.6% during the first week of AD. The amount of volatile fatty acids (VFA) did not exceed the threshold levels, which facilitated the smooth operation of AD. The BMP was found highest in KG (289.7 mL/g VS), followed by RH (283.3 mL/g VS), and WR (269.7 mL/g VS) which is significantly higher than previously reported studies. The modified Gompertz model showed the best fit, followed by logistic and transference function models. The observed results signpost the tremendous potential of waste biomass particularly KG, RH and WR to produce biomethane by DMC. This study provides crucial insights for optimizing BMP emphasizing the promising prospects of KG, RH, and WR for sustainable bioenergy applications.