Improved methane production from corn straw by microaerobic pretreatment with a pure bacteria system

Thermophilic microaerobic pretreatment has been proved to be efficient in improving methane production of corn straw in previous studies. In this study, the effect of mesophilic (37 degrees C) microaerobic pretreatment using Bacillus Subtilis on the anaerobic digestion of corn straw was explored. Microaerobic pretreatment with a pure bacteria system was beneficial for the anaerobic digestion of corn straw, which obviously improved the methane yield. The maximum methane yield of 270.8 mL/g VS was obtained at the oxygen load of 5 mL/g VS, which was 17.35% higher than that of untreated group. Groups with mesophilic microaerobic pretreatment obtained higher glucose and VFAs concentrations, as well as higher peroxidase activities after 24 h pretreatment. In addition, the X-ray diffraction (XRD) analysis displayed the crystallinity indexes of pretreated groups were also decreased. Therefore, microaerobic pretreatment with a pure bacteria system (Bacillus Subtilis) is an efficient pretreatment method to enhance the anaerobic digestion efficiency of cellulosic biomass.