The family methanosarcinaceae

Abstract

The family Methanosarcinaceae currently (January 2014) consists of nine genera: Methanosarcina (11 species, not including later subjective synonyms), Halomethanococcus (1 species), Methanimicrococcus (1 species), Methanococcoides (3 species), Methanohalobium (1 species), Methanohalophilus (3 species), Methanolobus (7 species), Methanomethylovorans (2 species), and Methanosalsum (1 species). This family of mesophilic or moderately thermophilic and neutrophilic or alkaliphilic and in some cases halophilic methanogens belongs to the order Methanosarcinales. The members are generally irregular coccoid in shape, and the cells of some species form large aggregates. Cells possess a protein S-layer wall, and some species also produce an outer heteropolysaccharide layer. The family Methanosarcinaceae is the most versatile of all families of methanogenic Archaea with respect to the diversity of substrates used for energy generation: methylated amines and methanol are generally used, many species can grow on H 2 /CO 2, some use acetate, and other substrates used by some are dimethyl sulfide, methanethiol, and even carbon monoxide. The mol% G+C of the DNA varies between 36 and 48. Members of the Methanosarcinaceae have been found in a wide variety of anaerobic environments where methane is produced: freshwater, marine and hypersaline sediments, wetlands, thermal environments, oil wells, anaerobic waste treatment systems, and gastrointestinal tracts of animals.