Methanosarcina mazei

M. mazei was first discovered by Mazé in 1915 (described as Pseudosarcina) and first named in 1936 by Albert Barker. M. mazei can be found in fresh water and marine sediments, as well as permafrost. ==Morphology==

Methanosarcina mazei has coccoid cells around 1–3 microns in diameter that aggregate together with S-layers and a methanochondroitin outer layer in freshwater, and grow as single cells with S-layer coatings in higher salinities. M. mazei can produce an enzyme, disaggregatase, to switch from aggregates to single cells. The S-layer of M. mazei consists primarily of the protein MM1976, which contains five glycosylation sites. ==Genome==

Methanosarcina mazeis genome consists of a single circular chromosome of around 4.1 Mbp with 3371 protein encoding genes. has an average intergenic region of 303 bp, a coding region of 75.15%, and a GC content around 41%. Genes suspected to have been gained from horizontal gene transfer appear scattered throughout the genome, suggesting M. mazei has accepted genes from many hosts. == Growth Requirements and Metabolism ==

M. mazei grows between 8 and 45 °C, with an optimal temperature of 40 °C. Its optimum pH is 7.2 but can tolerate pHs between 5.5 and 8.5. ammonium concentrations of 3 g/L, and volatile fatty acid concentrations up to 10 g/L. To respond to salinity stress, M. mazei can produce N-acetyl-β-lysine and transport glycine-betaine. and an F420H2 dehydrogenase. M. mazei can utilize a variety of carbon sources for methanogenesis, including CO2, acetate, methanol, and methylamines. M. mazei can receive electrons from Geobacter species through direct interspecies electron transfer (DIET). It does not require a multiheme cytochrome to participate in DIET. == Biotechnology Applications ==

M. mazei offers potential as a source of bioplastic production, pollutant degradation, and heavy metal bioremediation. Its tolerance for organic acids, ammonia, and salinity could make it a useful production microbe, and many tools to engineer it have been created, including CRISPR, inducible promoters, and the use of pyrrolysyl-tRNA synthetases for codon expansion. ==References==