Hocq Rémi, Horvath Josef, Stumptner Maja, Malevičius Mykolas, Thallinger Gerhard G, Pflügl Stefan
Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
Christian Doppler Laboratory for Optimized Expression of Carbohydrate-active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
Nat Commun. 2025 May 6;16(1):4217. doi: 10.1038/s41467-025-59103-8.
Acetogens are promising industrial biocatalysts for upgrading syngas, a gas mixture containing CO, H and CO into fuels and chemicals. However, CO severely inhibits growth of many acetogens, often requiring extensive adaptation to enable efficient CO conversion (carboxydotrophy). Here, we adapt the thermophilic acetogen Thermoanaerobacter kivui to use CO as sole carbon and energy source. Isolate CO-1 exhibits rapid growth on CO and syngas (co-utilizing CO, H and CO) in batch and continuous cultures (µ ~ 0.25 h). The carboxydotrophic phenotype is attributed to the mobilization of a CO-dependent megatransposon originating from the locus responsible for autotrophy in T. kivui. Transcriptomics reveal the crucial role the redox balance plays during carboxydotrophic growth. These insights are exploited to rationally engineer T. kivui to grow on CO. Collectively, our work elucidates a primary mechanism responsible for the acquisition of carboxydotrophy in acetogens and showcases how transposons can orchestrate evolution.
产乙酸菌是用于合成气升级的有前景的工业生物催化剂，合成气是一种包含一氧化碳、氢气和二氧化碳的气体混合物，可转化为燃料和化学品。然而，一氧化碳严重抑制许多产乙酸菌的生长，通常需要长时间适应才能实现高效的一氧化碳转化（羧营养）。在此，我们使嗜热产乙酸菌基维嗜热厌氧杆菌适应以一氧化碳作为唯一碳源和能源。分离出的菌株CO-1在分批培养和连续培养中（μ约为0.25 h⁻¹）能在一氧化碳和合成气（共利用一氧化碳、氢气和二氧化碳）上快速生长。这种羧营养表型归因于一个依赖一氧化碳的巨型转座子的移动，该转座子源自基维嗜热厌氧杆菌中负责自养的基因座。转录组学揭示了氧化还原平衡在羧营养生长过程中所起的关键作用。利用这些见解对基维嗜热厌氧杆菌进行合理改造，使其能在一氧化碳上生长。总体而言，我们的工作阐明了产乙酸菌获得羧营养的主要机制，并展示了转座子如何推动进化。
