Moritella profunda sp nov and Moritella abyssi sp nov., two psychropiezophilic organisms isolated from deep Atlantic sediments

Strains 2674(T) (= LMG 21259(T) =JCM 11435(T)) and 2693(T) (= LMG 21258(T) =JCM 11436(T)) were isolated from Atlantic sediments at a temperature of 2 degreesC and a depth of 2815 m off the West African coast. Polyphasic evidence indicates that the two strains belong to the genus Moritella and represent distinct species, for which the names Moritella profunda sp. nov. (for strain 2674(T)) and Moritella abyssi sp. nov. (for strain 2693(T)) are proposed. The moderate piezophily of the two organisms is intermediate between that of the type species, Moritella marina, which is not piezophilic, and Moritella yayanosii, an obligate piezophile. Both are strict psychrophiles with slightly different cardinal temperatures: at 0(.)1 MPa, maximal growth rates are observed at 2degreesC (M. profunda) and 4degreesC (M. abyssi) with maximum temperatures of 12degreesC (M. profunda) or 14 degreesC (M. abyssi). The optimal pressure is lower than that at the site of isolation, and raising the temperature to 10 degreesC makes the organisms more piezophilic.