Methane production performances of different compositions in lignocellulosic biomass through anaerobic digestion

Abstract Lignocellulosic biomass holds great potential in the production of renewable energy such as biomethane via anaerobic digestion. However, the digestion performance of the three main compositions of lignocellulose during biogas production is not well understood so far, and this has greatly hindered the efficient use of biomass by anaerobic fermentation. In this study, the anaerobic digestion performances of glucose, cellulose, hemicellulose, lignin, and their combinations in biomethane production were investigated. The biomethane production potential of cellulose was higher than that of hemicellulose and lignin, and high crystallinity cellulose shows adverse impact on methane production. Hemicellulose had a fast hydrolysis rate and was easier to be digested than cellulose, but it also easily led to excessive acids accumulation. Lignin showed a very limited potential in biomethane production. The co-fermentation of cellulose and hemicellulose could promote cellulose conversion and eliminate the over-acidification of hemicellulose, resulting in efficient and stable biogas production. The co-fermentation of lignin with cellulose and hemicellulose showed an inhibition in biomethane production, and lignin with different structure and sulfur content had different degree of inhibition. This study provides insights into the mechanisms of anaerobic fermentation of lignocellulosic biomass, and paves the way for the better use of biomass.