Methylobrevis pamukkalensis gen. nov., sp nov., a halotolerant restricted facultative methylotroph isolated from saline water

An aerobic halotolerant restricted facultatively methylotrophic bacterium was isolated from a saline hot spring in Pamukkale, Turkey, and designated strain PK2(T). The cells of this strain were Gram-stain-negative, asporogenous, motile short rods multiplying by binary fission. They utilized methanol, methylamine and mannitol as carbon and energy sources. The organism grew optimally at 30 degrees C in media containing 85 mM NaCl and at pH 7.5-8.0. C-1 cmpounds were assimilated via the isocitrate-Iyase-positive variant of the serine pathway. Poly-beta-hydroxybutyrate and the compatible solute ectoine were found in the cells. The dominant phospholipids were phosphatidylethanolamine and phosphatidylmonomethylethanolamine. The major cellular fatty acids of methanol-grown cells were C-18:1 omega 7 and C-16:1 omega 7c. The main ubiquinone was Q-10. The DNA G+C content was 67.9 mol% (T-m). The 16S rRNA gene sequence suggests that strain PK2(T) is affiliated with the order Rhizobiales within the class Alphaproteobacteria, being most closely related to Mesorhizobium gobiense CCBAU 83330(T) (94% similarity). A novel genus and species, Methylobrevis pamukkalensis gen. nov., sp. nov., is proposed on the basis of phenotypic and genotypic data, with PK2(T) (VKM B-2849(T)=JCM 30229(T)) as the type strain.