Diender Martijn, Uhl Philipp S, Bitter Johannes H, Stams Alfons J M, Sousa Diana Z
Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
Bio-based Chemistry & Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
ACS Sustain Chem Eng. 2018 Feb 5;6(2):2169-2176. doi: 10.1021/acssuschemeng.7b03601. Epub 2017 Dec 11.
Carbon monoxide-fermenting microorganisms can be used for the production of a wide range of commodity chemicals and fuels from syngas (generated by gasification of, e.g., wastes or biomass) or industrial off-gases (e.g., from steel industry). Microorganisms are normally more resistant to contaminants in the gas (e.g., hydrogen sulfide) than chemical catalysts, less expensive and self-regenerating. However, some carboxydotrophs are sensitive to high concentrations of CO, resulting in low growth rates and productivities. We hypothesize that cultivation of synthetic cocultures can be used to improve overall rates of CO bioconversion. As a case study, a thermophilic microbial coculture, consisting of and was constructed to study the effect of cocultivation on conversion of CO-rich gases to methane. In contrast to the methanogenic monoculture, the coculture was able to efficiently utilize CO or mixtures of H/CO/CO to produce methane at high efficiency and high rates. In CSTR-bioreactors operated in continuous mode, the coculture converted artificial syngas (66.6% H:33.3% CO) to an outflow gas with a methane content of 72%, approaching the 75% theoretical maximum. CO conversion efficiencies of 93% and volumetric production rates of 4 m/m/day were achieved. This case shows that microbial cocultivation can result in a significant improvement of gas-fermentation of CO-rich gases.
一氧化碳发酵微生物可用于从合成气（例如由废物或生物质气化产生）或工业废气（例如来自钢铁行业）生产多种商品化学品和燃料。微生物通常比化学催化剂对气体中的污染物（例如硫化氢）更具抗性，成本更低且可自我再生。然而，一些一氧化碳营养菌对高浓度的一氧化碳敏感，导致生长速率和生产率较低。我们假设合成共培养物的培养可用于提高一氧化碳生物转化的总体速率。作为一个案例研究，构建了一种由 和 组成的嗜热微生物共培养物，以研究共培养对富含一氧化碳的气体转化为甲烷的影响。与产甲烷单培养物相比，该共培养物能够高效且高速地有效利用一氧化碳或氢气/一氧化碳/二氧化碳的混合物来生产甲烷。在以连续模式运行的连续搅拌釜式生物反应器中，该共培养物将人工合成气（66.6%氢气:33.3%一氧化碳）转化为甲烷含量为72%的流出气体，接近75%的理论最大值。实现了93%的一氧化碳转化效率和4立方米/立方米/天的体积产率。这个案例表明，微生物共培养可以显著提高富含一氧化碳气体的气体发酵效果。
