Biomethane production by typical straw anaerobic digestion: Deep insights of material compositions and surface properties

Abstract

Straws as lignocellulosic agricultural biomass have a huge amount and are widely used for biomethane production by anaerobic digestion (AD). However, the mechanism of impacts of straw composition and surface properties on biomethane production remain unclear. Here, a lab-scale AD incubation experiment was conducted and the characterization of four types of straws (corn straw, wheat straw, sweet sorghum straw, and rice straw) were also determined. The straw compositions and net cumulative methane production showed significant difference. Although the relative contents of key organic components and carbon had no significant correlation to the biomethane production (r = -0.36, P > 0.05), there existed differences of non-polar characteristics, steric hindrance effect and special surface morphology in four types of straws, indicating that the surface characteristics affected anaerobic biomethane production process. In addition, the straw matrix associating with silicon might hinder the biotransformation.