Li Shubing, Peng Zhenzhen, Xie Shuguang, Chen Weiqi, Zhu Ying, Huang Wenwen, Tang Yi, Lu Mengchen, Chen Xunsen, Guo Teng, Wei Fangrong, Ye Jinshao, Zhao Ling, Long Yan
Key Laboratory of Environmental Exposure and Health of Guangdong Province, College of Environment and Climate, Jinan University, Guangzhou 510632 Guangdong Province, China.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Bioresour Technol. 2025 Dec;437:133078. doi: 10.1016/j.biortech.2025.133078. Epub 2025 Aug 5.
Recent research has identified the Actinobacterium Candidatus Mycobacterium methanotrophicum, which oxidizes methane aerobically in extremely acidic environments. In a previous study, we observed significant enrichment of Actinobacteria in an anaerobic iron-rich methane-oxidation reactor. Therefore, in this study, we assessed the anaerobic methane utilization potential of Actinobacteria using microcosm experiments, isotope labeling, and DNA stable isotope probing. Metabolic pathway analysis indicated that Actinobacteria harbor genetic potential for multiple pathways in iron-rich anaerobic environments. Additionally, we propose that Propionibacteriales may activate methane using oxygen produced by Rhodospirillales through iron-containing methanobactin analog-dependent HO reduction. The resulting intermediates of methane oxidation could serve as carbon and energy sources for these microorganisms. Actinobacteria were also involved in the conversion of nitrite to ammonia. Iron may be an important trigger in Actinobacteria mediating anaerobic methane oxidation. Our findings reveal the potential role of Actinobacteria in contributing to anaerobic methane oxidation in iron-rich environments through interbacterial cooperation.
