Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875701, Tempe, AZ 85287-5701, USA.
School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ85287- 5701, USA.
FEMS Microbiol Ecol. 2017 Jun 1;93(6). doi: 10.1093/femsec/fix076.
Microbial anaerobic conversion of carbon monoxide (CO) and syngas (mainly composed of CO, CO2 and H2) leads to the production of important industrial products, such as acetate and ethanol. The composition of CO- and syngas-converting microbial communities and the microbial interactions involved are still largely unknown. The main objectives of this study were (i) to understand the effects of CO, CO2, and H2 on the structure and function of a CO-consuming microbial community, and (ii) to identify key carboxidotrophs in the mixed culture. For this, sludge was anaerobically enriched with CO as the sole carbon/energy source at incrementally increasing CO partial pressures (PCO). Phylotypes of Methanobacteriaceae and methane production were detected at PCO ≤ 44.1 kPa. At higher PCO, enriched phylotypes were Acetobacterium, Oscillospira and Pleomorphomonas, and acetate was the main end product. The addition of CO2/HCO3- or H2 to CO fermentation increased the acetate/ethanol ratio and species diversity, compared to growth with CO as sole substrate. Phylotypes associated with Pleomorphomonas and Acetobacterium increased in relative abundance during exponential CO utilization. The Pleomorphomonas-like isolate produced H2:CO2, whereas the Acetobacterium-like isolate produced ethanol, when CO was the only electron/carbon source. These findings shed light on the interplay between syngas components and microbial communities.
微生物的厌氧转化一氧化碳（CO）和合成气（主要由 CO、CO2 和 H2 组成）会导致生产重要的工业产品，如乙酸盐和乙醇。CO 和合成气转化微生物群落的组成以及涉及的微生物相互作用在很大程度上仍然未知。本研究的主要目的是（i）了解 CO、CO2 和 H2 对消耗 CO 的微生物群落结构和功能的影响，以及（ii）鉴定混合培养物中的关键羧化菌。为此，在逐渐增加 CO 分压（PCO）的条件下，用 CO 作为唯一的碳/能源对污泥进行厌氧富集。在 PCO≤44.1 kPa 时检测到甲烷杆菌科的生物型和甲烷的产生。在更高的 PCO 下，富集的生物型为乙酸菌属、螺旋菌属和变形菌属，乙酸是主要的终产物。与仅以 CO 为底物相比，向 CO 发酵中添加 CO2/HCO3-或 H2 会增加乙酸/乙醇的比值和物种多样性。在 CO 利用的指数期，与 Pleomorphomonas 和 Acetobacterium 相关的生物型的相对丰度增加。当 CO 是唯一的电子/碳源时，类似变形菌的分离物产生 H2:CO2，而类似乙酸菌的分离物产生乙醇。这些发现揭示了合成气成分与微生物群落之间的相互作用。
