Methylobacterium variabile sp. nov., a methylotrophic bacterium isolated from an aquatic environment.

Strain GR3(T) was isolated from drinking water during a screening programme to monitor the bacterial population present in the distribution system of Seville (Spain), and it was studied phenotypically, genotypically and phylogenetically. This pink-pigmented bacterium was identified as a Methylobacterium sp. Members of this genus are distributed in a wide variety of natural habitats, including soil, dust, air, freshwater and aquatic sediments. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain GR3(T) was closely related to Methylobacterium aquaticum (97.4% sequence similarity), whereas sequence similarity values with respect to the rest of the species belonging to this genus were lower than 96%. Furthermore, the DNA-DNA hybridization data and its phenotypic characteristics clearly indicate that the isolate represents a novel Methylobacterium species, for which the name Methylobacterium variabile sp. nov. is proposed. GR3(T) (=DSM 16961(T)=CCM 7281(T)=CECT 7045(T)) is the type strain; the DNA G+C content of this strain is 69.2 mol%.