Methanosarcina acetivorans

Methanosarcina acetivorans is a strictly anaerobic methane-producing archaeon (methanogen) that was isolated from marine sediment beneath a kelp bed in the Sumner branch of Scripps Canyon near La Jolla, California, in 1984. Over the years it has become a primary model to understand the genetics, biochemistry, and physiology of methanogens, microbes that play a critical role in several biogeochemical cycles, impact climate change, and have biotechnological value. The utility of M. acetivorans as a model is due in part to its extensive metabolic versatility. For example, it can grow by producing CH4 and CO2 using acetate, methylated substrates, or CO. Notably, M. acetivorans has been instrumental in elucidating key aspects of the aceticlastic pathway of methanogenesis in Methanosarcina, one of only two genera capable of using acetate to produce methane, which accounts for two-thirds of all methane biologically produced. M. acetivorans also has robust genetic tools. Genetic engineering of M. acetivorans has, for example, expanded its substrate range, increased its resistance to oxidants, converted it to an acetogen, and increased its ability to oxidize methane (reverse methanogenesis). M. acetivorans is also the first methanogen with clustered regularly interspaced short palindromic repeats (CRISPR) gene editing and CRISPR interference systems, firmly establishing M. acetivorans as a key platform for basic and applied methanogen research for years to come.