Methanocaldococcus vulcanius M7

Methanocaldococcus vulcanius (strain ATCC 700851 / DSM 12094 / M7) is an anaerobic, autotrophic, hyperthermophilic methanogen archaeon isolated from a deep-sea hydrothermal chimney sample collected on the East Pacific Rise at a depth of 2600 m. The temperature range for growth at pH 6.5 is 49-89 degrees Celsius, with optimum growth at 80 degrees Celsius. The optimum pH for growth is 6.5, and the optimum NaCl concentration for growth is around 25 g/l. It uses H2 and CO2 as the only substrates for growth and methane production. Tungsten, selenium and yeast extract stimulate growth significantly. In the presence of CO2 and H2, the organism reduces elemental sulphur to hydrogen sulphide. Growth is inhibited by chloramphenicol and rifampicin, but not by ampicillin, kanamycin, penicillin and streptomycin. As determined by 16S rDNA gene sequence analysis, this organism is closely related to Methanococcus jannaschii (strain JAL-1T). However, despite the high percentage of similarity between their 16S rDNA sequences (97.1%), the DNA-DNA hybridization levels between these strains are less than 5%. On the basis of these observations and physiological traits, it is proposed that this organism should be placed in a new species, Methanococcus vulcanius. (Adaptated from PMID: 10319479). (HAMAP: METVM)