Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China; College of Life Sciences, Jiangxi Normal University, Nanchang 330022, China.
Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China.
Water Res. 2024 Aug 15;260:121898. doi: 10.1016/j.watres.2024.121898. Epub 2024 Jun 11.
Syntrophy achieved via microbial cooperation is vital for anaerobic hydrocarbon degradation and methanogenesis. However, limited understanding of the metabolic division of labor and electronic interactions in electro-stimulated microbiota has impeded the development of enhanced biotechnologies for degrading hydrocarbons to methane. Here, compared to the non-electro-stimulated methanogenic toluene-degrading microbiota, electro-stimulation at 800 mV promoted toluene degradation and methane production efficiencies by 11.49 %-14.76 % and 75.58 %-290.11 %, respectively. Hydrocarbon-degrading gene bamA amplification and metagenomic sequencing analyses revealed that f_Syntrophobacteraceae MAG116 may act as a toluene degrader in the non-electro-stimulated microbiota, which was proposed to establish electron syntrophy with the acetoclastic methanogen Methanosarcina spp. (or Methanothrix sp.) through e-pili or shared acetate. In the electro-stimulated microbiota, 37.22 ± 4.33 % of Desulfoprunum sp. (affiliated f_Desulfurivibrionaceae MAG10) and 58.82 ± 3.74 % of the hydrogenotrophic methanogen Methanobacterium sp. MAG74 were specifically recruited to the anode and cathode, respectively. The potential electrogen f_Desulfurivibrionaceae MAG10 engaged in interspecies electron transfer with both syntroph f_Syntrophobacteraceae MAG116 and the anode, which might be facilitated by c-type cytochromes (e.g., ImcH, OmcT, and PilZ). Moreover, upon capturing electrons from the external circuit, the hydrogen-producing electrotroph Aminidesulfovibrio sp. MAG60 could share electrons and hydrogen with the methanogen Methanobacterium sp. MAG74, which uniquely harbored hydrogenase genes ehaA-R and ehbA-P. This study elucidates the microbial interaction mechanisms underlying the enhanced metabolic efficiency of the electro-stimulated methanogenic toluene-degrading microbiota, and emphasizes the significance of metabolic and electron syntrophic interactions in maintaining the stability of microbial community functionality.
微生物协同作用产生的共代谢对于厌氧烃降解和产甲烷至关重要。然而，由于对电刺激微生物群落中代谢分工和电子相互作用的理解有限，阻碍了增强生物技术从烃类降解为甲烷的发展。在这里，与非电刺激的产甲烷甲苯降解微生物群落相比，800 mV 的电刺激分别将甲苯降解和甲烷生产效率提高了 11.49%-14.76%和 75.58%-290.11%。烃降解基因 bamA 扩增和宏基因组测序分析表明，f_Syntrophobacteraceae MAG116 可能在非电刺激的微生物群落中充当甲苯降解菌，它通过 e-菌毛或共享乙酸与乙酸营养型产甲烷菌 Methanosarcina spp.（或 Methanothrix sp.）建立电子共代谢。在电刺激的微生物群落中，37.22±4.33%的 Desulfoprunum sp.（属 f_Desulfurivibrionaceae MAG10）和 58.82±3.74%的氢营养型产甲烷菌 Methanobacterium sp. MAG74 分别被专门招募到阳极和阴极。潜在的电生成菌 f_Desulfurivibrionaceae MAG10 与共代谢菌 f_Syntrophobacteraceae MAG116 和阳极进行种间电子转移，这可能是由 c 型细胞色素（例如 ImcH、OmcT 和 PilZ）介导的。此外，产氢电营养菌 Aminidesulfovibrio sp. MAG60 从外电路捕获电子后，可以与产甲烷菌 Methanobacterium sp. MAG74 共享电子和氢气，而后者则独特地拥有氢化酶基因 ehaA-R 和 ehbA-P。本研究阐明了增强的电刺激产甲烷甲苯降解微生物群落代谢效率的微生物相互作用机制，并强调了代谢和电子共代谢相互作用在维持微生物群落功能稳定性方面的重要性。
