玉米秸秆产生物燃气及其微生物群落解析

为研究玉米秸秆产沼气及其发酵过程中微生物群落变化，以预处理后的玉米秸秆为原料，采用10 L厌氧反应器进行批式中温发酵产沼气。同时取样利用454焦磷酸测序法测定发酵过程中微生物群落的变化。结果表明：该系统启动迅速，在第3 d就达到产气高峰7.78 L，料容产气率为0.97 L·L^-1·d^-1，46 d原料沼气产率和甲烷产率分别为236.84 ml·（g VS）^-1和132.23 ml·（g VS）^-1。454焦磷酸测序及分析表明系统中古菌主要为甲烷微菌纲（Methanomicrobia，占总OTU的89.63%），其次为热原体纲（Thermoplasmata，8.51%）古菌。发酵系统中共有22～29个细菌门，其中优势菌群为拟杆菌门（Bacteroidetes，平均含量46.07%）、变形菌门（Proteobacteria，平均含量20.51%）和厚壁菌门（Firmicutes，平均含量13.09%）。玉米秸秆沼气系统微生物群落结构的阐明可为秸秆沼气工程调控提供科学数据。

Biogas production using cornstalks and prokaryotic community composition

With pretreated cornstalks as raw material, a mesophilic batch fermentation study using a 10-L anaerobic reactor was carried out to investigate biogas production rate and prokaryotic composition. Fermentation started rapidly, and a peak in biogas production appeared after 3 days with volumetric gas production rate of 0.97 L·L^-1·d^-1. The rates of biogas production and methane production during 46 days were 236.84 ml·(g VS)^-1 and 132.23 ml·(g VS)^-1, respectively. During the fermentation process, prokaryotic composition was investigated using pyrosequencing technique. Prokaryotic diversity increased with the fermentation process, and prokaryotic composition shifted dramatically compared to the initial stage. Archaea was dominated by Methanomicrobia (89.63% of total archaeal reads), followed by Thermoplasmata (8.51%). About 22-29 bacterial phyla were identified, including Bacteroidetes (46.07% of total reads), Proteobacteria (20.51%), and Firmicutes (13.09%) as the predominant bacterial communities. Our research provides important implications on the regulation of prokaryotic composition for biogas production using cornstalks.