北京市北神树生活垃圾填埋场产甲烷菌的群落结构和演替规律

产甲烷菌是填埋场稳定化的关键微生物.以北京市北神树垃圾填埋场为采样地,钻井采集了填埋深度6~36.1 m,填埋时间2~15 a的垃圾样品.采用PCR检验其中产甲烷菌的种类,并基于QPCR技术获得的数据,研究了各类产甲烷菌随时间和深度的数量变化,及其与垃圾化学性质之间的关系.发现堆体内有机质含量基本稳定,p H呈弱碱性,符合产甲烷阶段的化学特性.检测出两类乙酸营养型产甲烷菌(Methanosaeta和Methanosarcina),一类氢营养型产甲烷菌(Methanobacterials).随着填埋时间的延长,产甲烷菌呈现出先升高后下降的趋势,填埋9 a以上的垃圾中产甲烷菌群落结构趋于稳定.乙酸营养型的Methanosarcina为优势类群.三类产甲烷菌的含量与挥发性脂肪酸含量显著相关,与各类大分子有机质含量相关性很弱或不相关,表明产甲烷菌的数量受底物含量的影响,而在填埋2 a以上的垃圾中,大分子水解、发酵等作用对产甲烷菌影响微弱.

Community Structure and Succession of Methanogens in Beishenshu Landfill, Beijing

Methanogens are the key microorganisms for landfill stabilization. RT-PCR and qPCR detecting system were employed to determine the types and abundance of methanogens in 2-15 year-old solid wastes that sampled from Beishenshu Landfill, Beijing. The organic components were almost stable and the pH values were in alkaline range, which indicated that the landfill was in the methanogenic process. Methanobacterials, Methanosaeta, and Methanosarcina were detected, among which Methanosaeta and Methanosarcina are acetoclastic, and Methanobacterials are hydrogenotrophic. As landfill processing, within this time range, although the bacterial abundance was significantly decreased, the amount of methanogens was first increased and then decreased, and finally became stable after being landfilled for 9 years. Methanosarcina was the dominate taxa. Significant correlations were found between the methanogens and the volatile fatty acids, but the correlations between methanogens and larger molecular organic matters were relatively weak or even absent. Taken together, our study revealed that the amount of methanogens were affected by substrates, but hardly influenced by the conversion of large molecules in these wastes landfilled for more than 2 years.