Genomic and enzymatic evidence of acetogenesis by anaerobic methanotrophic archaea

• Published in: Nature communications Vol. 11; no. 1; p. 3941
• Main Authors: Yang, Shanshan, Lv, Yongxin, Liu, Xipeng, Wang, Yinzhao, Fan, Qilian, Yang, Zhifeng, Boon, Nico, Wang, Fengping, Xiao, Xiang, Zhang, Yu
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 07.08.2020; Nature Publishing Group UK; Nature Portfolio
• Subjects: Acetate-CoA ligase; Acetic acid; Acetogenesis; Anaerobic processes; Archaea; Bioreactors; Biotechnology; Carbon; Carbon cycle; Cold; Computer simulation; Ecosystems; Fuels; Genomes; Heterotrophic microorganisms; High pressure; Hydrothermal plumes; Hydrothermal vents; Inorganic carbon; Marine ecosystems; Methane; Microbial activity; Microorganisms; Nuclear fuels; Organic carbon; Oxidation; Seepage; Vents; Volcanoes
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-17860-8

Abstract Anaerobic oxidation of methane (AOM) mediated by anaerobic methanotrophic archaea (ANME) is the primary process that provides energy to cold seep ecosystems by converting methane into inorganic carbon. Notably, cold seep ecosystems are dominated by highly divergent heterotrophic microorganisms. The role of the AOM process in supporting heterotrophic population remains unknown. We investigate the acetogenic capacity of ANME-2a in a simulated cold seep ecosystem using high-pressure biotechnology, where both AOM activity and acetate production are detected. The production of acetate from methane is confirmed by isotope-labeling experiments. A complete archaeal acetogenesis pathway is identified in the ANME-2a genome, and apparent acetogenic activity of the key enzymes ADP-forming acetate-CoA ligase and acetyl-CoA synthetase is demonstrated. Here, we propose a modified model of carbon cycling in cold seeps: during AOM process, methane can be converted into organic carbon, such as acetate, which further fuels the heterotrophic community in the ecosystem.