Petrotoga mexicana sp nov., a novel thermophilic, anaerobic and xylanolytic bacterium isolated from an oil-producing well in the Gulf of Mexico

A novel anaerobic, thermophilic, xylanolytic, motile rod-shaped bacterium with a sheath-like outer structure (toga) was isolated from a Mexican oil well in the Gulf of Mexico. Strain MET12(T) was a Gram-negative bacterium, reducing elemental sulfur, thiosulfate and sulfite to hydrogen sulfide. Its optimum growth conditions were 55 degreesC, pH 6(.)6, 3% NaCl and 0(.)15% MgCl2.6H(2)O. The DNA G + C content was 36(.)1 mol%. Phylogenetically, strain MET12(T) was related to members of genus Petrotoga, with similarities to Petrotoga mobilis, Petrotoga sibirica, Petrotoga miotherma and Petrotoga olearia varying from 97(.)6 to 98(.)8%. However DNA-DNA relatedness values between these species and strain MET12(T) were lower than 70%. As strain MET12(T) (=DSM 14811(T)=Clp 107371(T)) was genomically and phenotypically different from existing Petrotoga species, it is proposed as the type strain of a novel species, Petrotoga mexicana sp. nov.