Methylobacterium currus sp. nov., isolated from a car air conditioning system

A novel bacterial strain, designated PR1016A ^T , was isolated from a car air conditioning system. This rod-shaped strain showed catalase and oxidase activities, was aerobic and methylotrophic, and had a reddish pink colour. The genomic DNA G+C content of strain PR1016A ^T was 70.2 mol%, as determined by genome sequencing. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain PR1016A ^T was most closely related to Methylobacterium aquaticum GR16T (98.86 %), M. variabile GR3 ^T (98.43 %), M. platani PMB 02 ^T (98.36 %) and M. tarhaniae N4211 ^T (98.14 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain PR1016A ^T and M. aquaticum GR16 ^T , M. platani PMB02 ^T and M. variabile GR3 ^T were 88.61, 88.14 and 87.88 %, and 36.4, 35.8 and 34.7 %, respectively. Numerous insertion sequences are present in the genome of strain PR1016A ^T , which has a larger genome than the four Methylobacterium species described above. Cells grew at 18-42 °C (optimum, 30 °C), at pH 4.0-9.0 (optimum, pH 7.0) and in the presence of 0-1.0% (w/v) NaCl (optimum, 0 %). The major respiratory quinone was Q10. Fatty acid methyl ester analysis revealed that summed feature 8 (C _{18: 1ω7c} and/or C _{18: 1ω6c} ) was the predominant cellular fatty acid in strain PR1016AT. Two-dimensional TLC indicated that the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The genotypic and phenotypic characteristics indicate that strain PR1016A ^T represents a novel species of the genus Methylobacterium, for which the name Methylobacterium currus sp. nov. is proposed. The type strain is PR1016A ^T (=KACC 19662 ^T =JCM 32670 ^T ).