Abstract

厌氧消化是一个复杂的微生物过程，涉及的微生物种类繁多。乙酸盐是一种重要的中间产物，乙酸氧化菌和古细菌之间的相互作用在缺氧环境中甲烷形成起重要作用。已知高温厌氧消化会增加甲烷产量，但对微生物群落的影响基本是未知的。本研究中，采用稳定同位素探针法来表征嗜热厌氧消化中的乙酸盐和乳酸盐氧化细菌。在饲喂13C-乙酸盐的微环境中，与梭菌属，食虫氢菌、嗜热菌、螺毛菌、鲎菌和红球菌成员相关的细菌表现出13C - DNA组分的高丰度，表明它们在乙酸盐氧化中具有活性。在添加13C-乳酸盐的处理中，发现厌氧杆菌，脱硫菌、合成菌、囊菌和偶氮螺旋杆菌是潜在的嗜热乳酸盐利用者。 PICRUSt预测，与硝酸盐和亚硝酸盐还原相关的酶将在13C-DNA组分中富集，表明乙酸盐和乳酸盐氧化可能与硝酸盐和/或亚硝酸盐还原相偶联。共生网络分析表明不富含13C-DNA部分的细菌类群，也可能在嗜热厌氧消化中起关键作用。

Anaerobic digestion is a complicated microbiological process that involves a wide diversity of microorganisms. Acetate is one of the most important intermediates, and interactions between acetate-oxidizing bacteria and archaea could play an important role in the formation of methane in anoxic environments. Anaerobic digestion at thermophilic temperatures is known to increase methane production, but the effects on the microbial community are largely unknown. In the current study, stable isotope probing was used to characterize acetate- and lactate-oxidizing bacteria in thermophilic anaerobic digestion. In microcosms fed 13C-acetate, bacteria related to members of Clostridium, Hydrogenophaga, Fervidobacterium,Spirochaeta, Limnohabitans, and Rhodococcus demonstrated elevated abundances of 13C-DNA fractions, suggesting their activities in acetate oxidation. In the treatments fed 13C-lactate,Anaeromyxobacter, Desulfobulbus, Syntrophus, Cystobacterineae, and Azospira were found to be the potential thermophilic lactate utilizers. PICRUSt predicted that enzymes related to nitrate and nitrite reduction would be enriched in 13C-DNA fractions, suggesting that the acetate and lactate oxidation may be coupled with nitrate and/or nitrite reduction. Co-occurrence network analysis indicated bacterial taxa not enriched in 13C-DNA fractions that may also play a critical role in thermophilic anaerobic digestion.

https://link.springer.com/article/10.1007/s00248-017-1017-8