Biologists sniff out another method that microbes use to make methane

News brief: Every year, microbes produce hundreds of millions of tons of methane, a greenhouse gas that’s more potent than carbon dioxide. Scientists had thought the job was done exclusively through methanogenesis. But in the journal Nature Microbiology, a research team led by the University of Washington’s Caroline Harwood lays out an alternate method that makes use of a backup enzyme called iron-only nitrogenase. “Our findings are significant because they give scientists a second target to chase in understanding biological methane formation and rising methane emissions,” Utah State University’s Lee Seefeldt said in a news release. “In addition, the discovery could drive efforts to turn waste gases into usable fuels.”

This animation shows how a nitrogen-fixing microbe, Rhodopseudomonas palustris, can also produce methane using iron-only nitrogenase and how, in a lab culture, the methane can support the growth of a methane-utilizing Methylomonas.

In addition to Seefeldt and Harwood, who is the study’s senior author, the researchers behind the Nature Microbiology study, “A Pathway for Biological Methane Production Using Bacterial Iron-Only Nitrogenase,” include UW lead author Yanning Zheng, Derek Harris, Zheng Yu, Yanfen Fu, Saroj Poudel, Rhesa Ledbetter, Kathryn Fixen, Zhi-Yong Yang, Eric Boyd and Mary Lidstrom.

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