Anaerobic Digestion of Lignocellulosic Wastes by Rumen Microorganisms: Chemical and Kinetic Analyses

A huge volume of lignocellulosic wastes is currently produced worldwide. Anaerobic digestion is an effective disposal method for these wastes because of its low cost and environmental benefits. The utilization of the produced methane-rich biogas can reduce the dependence of energy on fossil fuels and reduce the emission of greenhouse gas. However, the recalcitrant structure of lignocelluloses in these wastes is the barrier for the hydrolysis of lignocelluloses by microorganisms. Many microbial resources have been used for improving the hydrolysis, among which, rumen microorganisms have shown some advantages because of their high cellulolytic activities. The characteristics and structure changes of lignocelluloses in biological conversion have been investigated with chemical and imaging analysis to determine which characteristics are responsible for limiting the microbial hydrolysis and which changes benefit for the bioconversion. This chapter describes the recent results of chemical analysis using atomic force microscopy (AFM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), GC/MS, and X-ray diffraction (XRD) on the biological conversion of lignocellulosic wastes, and especially on the anaerobic digestion of lignocellulosic wastes by rumen microorganisms, and kinetic analysis of such a bioconversion.