Keywords: 
• steam exploded stalk /
• thermophilic /
• solid-state fermentation /
• biogas /
• condition optimization

Abstract: Biogas production by submerged culture and the physical, chemical, biological pretreatment of stalk have encountered with some key problems, such as low efficiency and serious pollution. Based on it, steam explosion pretreatment method and solidstate fermentation have been researched in biogas production from corn stalk. After steam explosion pretreatment, methane yield from corn stalk reached 138.2 mL/g TS, at thermophilic condition of 50℃, by solidstate fermentation. With the single factor experimental optimization, the optimal conditions obtained were as follows: 1∶7 of solidliquid ratio, 7.5 of initial pH, 35% of inoculum size,0.04 g of NH4HCO3 addition per gram dry steam exploded corn stalk, 30 IU of cellulase addition per gram dry steam exploded corn stalk and 50℃ of fermentation temperature. Under the above controlled experimental conditions, the methane yield of steam exploded corn stalk was high up to 153.0 mL/g TS, which was 2.9 times of that with no steam explosion pretreatment. The degradation rate of cellulose and hemicellulose after fermentation was 59.86% and 67.22%, respectively. Therefore, steam explosion pretreatment help improve the biogas production of corn stalk effectively with high degradation rate. Thermophilic solid-state fermentation could shorten the lag phase, enhance the biogas production efficiency. Meantime, the fermentation process produces less wastewater, which is friendly to the environment.