Microbacterium lacusdiani sp. nov., a phosphate-solubilizing novel actinobacterium isolated from mucilaginous sheath of Microcystis

Abstract

A novel actinobacterium, designated strain JXJ CY 01^T, was isolated from a mucilaginous sheath of Microcystis aeruginosa FACHB-905 collected from Lake Dianchi, south-west China. Taxonomic position of the isolate was determined by polyphasic approaches. Strain JXJ CY 01^T shared 16S rRNA sequence similarities of 98.9 and 98.0% with Microbacterium marinilacus YM11-607^T and Microbacterium paludicola US15^T, and less than 98% with other members of the genus Microbacterium. The DNA-DNA relatedness values between strains JXJ CY 01^T and M. marinilacus JCM 16546^T and M. paludicola JCM 14308^T were 53.5±1.4 and 53.8±2.1%, respectively. l-Ornithine was detected in the cell wall, and rhamnose, galactose, glucose, arabinose, fucose and mannose as signature sugars in the whole-cell hydrolysates. Other chemotaxonomic characteristics determined were MK-12 and MK-11 as predominant menaquinones, anteiso-C_15:0, iso-C_16:0, anteiso-C_17:0 and iso-C_17:0 as major cellular fatty acids (>10%), and diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and two unidentified phospholipids as the polar lipids. The DNA G+C content was 70.4 mol%. On the basis of the above taxonomic data, strain JXJ CY 01^T is determined to represent a novel species of the genus Microbacterium, for which the name Microbacterium lacusdiani sp. nov. is proposed. The type strain is JXJ CY 01^T (= KCTC 29655^T=DSM 29188^T). The type strain JXJ CY 01^T can solubilize both insoluble inorganic (calcium phosphate) and organic phosphate (l-α-phosphatidylcholine) and is possibly one of the mechanism for enhancement of growth of M. aeruginosa FACHB-905.