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 °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.