Frigoribacterium mesophilum sp. nov., a mesophilic actinobacterium isolated from Bigeum Island, Korea.

A taxonomic study was performed on strain MSL-08T, which was isolated from a soil sample collected from Bigeum Island. The novel isolate was aerobic and Gram-positive. Cells were short and motile rods. Growth temperature ranged from 20 to 28 degrees C and the pH for growth ranged from 6.5 to 12.0. The optimum growth temperature and pH were 28 degrees C and 7.3, respectively. The predominant menaquinone was MK-9. Cell wall analysis showed B-type peptidoglycan containing 2,4-diaminobutyric acid, alanine, glycine, glutamate and lysine. The diagnostic phospholipids were diphosphatidylglycerol and phosphatidylglycerol. The major fatty acids were ai-C15:0, i-C16:0, C18:1omega7c and ai-C17:0. The DNA G+C content was 67.5 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain MSL-08(T) had less than 97 % similarity to any recognized species of the genus Frigoribacterium. Frigoribacterium faeni DSM 10309T was found to be the closest neighbour (96.95 %) to the novel strain. Based on the 16S rRNA gene sequence analysis and phenotypic characteristics, it is proposed that strain MSL-08T represents a novel member of the genus Frigoribacterium for which the name Frigoribacterium mesophilum sp. nov. is proposed. The type strain is MSL-08T (=DSM 19442T=KCTC 19311T).