A two-stage anaerobic bioconversion of corn stover: Impact of pure bacterial pretreatment on methane production

Abstract

Abstract Biological pretreatment is feasible for enhancing methane generation with crop residues. Improvement of the degradation efficiency of cellulose has always been the key to improve methane yield. The role of an anaerobic and thermophilic bacterium, Caldicellulosiruptor sp. F32, on the degradation of corn stalk was investigated. A pure bacterial pretreatment system (0.20 v/v), with 20 times CFU of 2.20 × 108 was verified to be beneficial to the deterioration of corn stalk residues and the increase of methane output. The highest methane yield was 250.2 mL/g volatile solid, which was 28% higher than that from the untreated group. In group 4, the concentrations of glucose and volatile fatty acids were higher than those in other groups. Furthermore, the assays by Fourier-transform infrared spectra and X-ray diffraction revealed that the crystallinity indexes of pretreated groups declined. Hence, biology-based pretreatment using pure bacterial system, Caldicellulosiruptor sp. F32, is a potentially effective approach to improve the degradation efficiency of lignocellulosic biomass.