Patterns of syntrophic interactions in methanogenic conversion of propionate
Patterns of syntrophic interactions in methanogenic conversion of propionate
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DOI：
10.1007/s00253-021-11645-9
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发表时间：
2021-10-25
影响因子：
5
通讯作者：
He，Qiang
中科院分区：
文献类型：
--
作者：
Cao，Liu;Cox，Chris D.;He，Qiang
产甲烷是厌氧消化过程的核心。丙酸作为产甲烷的关键中间体的转化需要细菌和古生菌伙伴之间的同养相互作用。在这项研究中，建立了一系列以丙酸为唯一底物的产甲烷富集法，以鉴定特定参与丙酸合成转化的微生物种群。这些严格控制的丙酸富集物表现出功能稳定性，丙酸转化和甲烷产生一致；然而，产甲烷微生物群落经历了大量的时间动态，这对于理解厌氧消化中微生物群落聚集的机制具有重要意义。无论来源、丙酸浓度或培养物的时间动态，合养细菌被确定为共养丙酸转化中最丰富和最一致的细菌伙伴。相反，参与丙酸合成转化的产甲烷伙伴缺乏一致性，因为优势产甲烷菌随着工艺条件和时间动态的变化而变化。甲烷球菌群作为丙酸抑制水平的合成营养伙伴而特别丰富，这可能是因为在不利的环境条件下发挥作用的能力。在本研究建立的富集物中，丙酸完全通过转化为乙酸酯和氢气来进行合成丙酸。以合养细菌和甲烷菌为代表的对高浓度丙酸高度耐受的微生物种群，对于理解丙酸积累频繁的过程扰动过程中的产甲烷活性具有重要意义。要点·合养细菌是丙酸代谢中最一致的细菌伙伴。·不同的氢基因营养的产甲烷菌群可以作为合养伙伴。·甲烷囊菌作为耐受丙酸升高的产甲烷菌伙伴而出现。
Methanogenesis is central to anaerobic digestion processes. The conversion of propionate as a key intermediate for methanogenesis requires syntrophic interactions between bacterial and archaeal partners. In this study, a series of methanogenic enrichments with propionate as the sole substrate were developed to identify microbial populations specifically involved in syntrophic propionate conversion. These rigorously controlled propionate enrichments exhibited functional stability with consistent propionate conversion and methane production; yet, the methanogenic microbial communities experienced substantial temporal dynamics, which has important implications on the understanding of mechanisms involved in microbial community assembly in anaerobic digestion.Syntrophobacterwas identified as the most abundant and consistent bacterial partner in syntrophic propionate conversion regardless of the origin of the source culture, the concentration of propionate, or the temporal dynamics of the culture. In contrast, the methanogen partners involved in syntrophic propionate conversion lacked consistency, as the dominant methanogens varied as a function of process condition and temporal dynamics.Methanoculleuspopulations were specifically enriched as the syntrophic partner at inhibitory levels of propionate, likely due to the ability to function under unfavorable environmental conditions. Syntrophic propionate conversion was carried out exclusively via transformation of propionate into acetate and hydrogen in enrichments established in this study. Microbial populations highly tolerant of elevated propionate, represented bySyntrophobacterandMethanoculleus, are of great significance in understanding methanogenic activities during process perturbations when propionate accumulation is frequently encountered.Key points•Syntrophobacter was the most consistent bacterial partner in propionate metabolism.•Diverse hydrogenotrophic methanogen populations could serve as syntrophic partners.•Methanoculleus emerged as a methanogen partner tolerant of elevated propionate.