Methane production from solid-state anaerobic digestion of lignocellulosic biomass

Four lignocellulosic biomass feedstocks including corn stover, wheat straw, yard waste and leaves were evaluated for methane production via solid-state anaerobic digestion (SS-AD). Results showed that the highest methane yield was attained for corn stover (81.2 L kg−1 volatile solids (VS)), followed by wheat straw (66.9 L kg−1 VS), leaves (55.4 L kg−1 VS) and yard waste (40.8 L kg−1 VS) at a substrate to inoculum (S/I) ratio of 2. The methane production during SS-AD of tested lignocellulosic biomass followed the first-order kinetics model with correlation coefficients (r2) of 0.91–0.98. The main contributor to methane production during SS-AD of corn stover and wheat straw was the degradation of cellulose and hemicellulose while the degradation of extractives was more predominant in yard waste and leaves. An inverse linear relationship was obtained between the methane yield and the lignin content and a positive linear relationship was found between the methane yield and the enzymatic digestibility of the lignocellulosic biomass.

► Four types of lignocellulosic biomass feedstocks were evaluated for methane production during solid-state anaerobic digestion.
► Methane yield of crop residue was much higher than that of leaves and yard waste.
► Methane production follows simple first-order kinetics model.
► Methane yield was highly related to lignin content and enzymatic digestibility of lignocellulosic biomass.