Methanosaeta thermophila PT is also known as Methanosaeta thermophila DSM 6194.

Energy Production:
Methanosaeta thermophila DSM 6194 (archaea): methanogen, acetate is only substrate that supports growth and methane production, obligate anaerobe, optimal growth between 55-60°C, produces gas vacuoles.

Methanosaeta thermophila P T is a thermophilic obligately-aceticlastic methane-producing archaeon.   Although approximately two-thirds of all biogenic methane is derived from the methyl group of acetate, Methanosaeta is one of only two genera of methanoarchaea able to utilize acetate as a substrate for methanogenesis.   Methanosarcina , the only other genus of methanoarchaea able to utilize acetate, can use H₂/CO₂, dimethylsulfide, and methanethiol as well as methylated C 1 compounds as substrates.   Unlike the faster-growing Methanosarcina , which prefers methylated compounds to acetate, Methanosaeta is a specialist that utilizes only acetate.   Although studies indicate that these two genera share common features in aceticlastic methanogenesis, some notable differences have been reported.   For example, these genera employ different enzymes for the activation of acetate to acetyl-CoA, the first step in the acetate fermentation pathway.

Since the acetate concentration of most environments is low, growth of Methanosaeta is favored.   For example, acetate is the most important substrate for methanogenesis in rice fields.   Studies have shown that the concentration of acetate in flooded rice paddies is in the 5-100 m M range, well below the minimum threshold level for growth of Methanosarcina .   Although Methanosarcina species have been shown to be present, Methanosaeta species are the predominant acetate-utilizing methanoarchaea in flooded rice paddies.   Methanosaeta species also dominate the methanogenic population of microbial consortia in granular sludge digestors, codigestors treating municipal solid waste and sewage sludge, upflow anaerobic sludge blanket reactors, and anaerobic baffled reactors.   During start-up of anaerobic bioreactors, Methanosarcina species are often prevalent due to the high acetate concentration; however, as bioreactors stabilize and achieve optimum performance the acetate concentration decreases and Methanosaeta species replace Methanosarcina .   Overall, Methanosaeta is likely to be the predominant producer of methane from acetate over Methanosarcina.

Although Methanosarcina continues to be extensively studied both biochemically and genetically, studies on Methanosaeta have lapsed due to its slow growth (2-12 day doubling time) and lower growth yield.   Genomics offers an amenable approach to understanding the physiology of this microbe.   Furthermore, the lack of genomic information from Methanosaeta represents a critical gap in our knowledge of agriculturally and environmentally important methanoarchaea.   The addition of Methanosaeta to the methanoarchaeal genome sequence compilation offers an opportunity for significant insight into this difficult microbe and the unprecedented use of comparative genomic approaches to address the nature of these microbes and their biological impact and potential.