ABSTRACT
A novel bacterial strain, designated MK52T, was isolated from the phycosphere of Microcystis aeruginosa. Strain MK52T is a Gram-stain-negative, pink-pigmented, rod-shaped, strictly aerobic bacterium. In 16S rRNA phylogenetic analysis, the MK52T strain was most closely related to Rhizorhabdus wittichii RW1T (98.66â%) and Rhizorhabdus histidinilytica UM2T (98.51â%). The genomic DNA G+C content of strain MK52T was calculated to be 65.5âmol%. The average nucleotide identity values of strain MK52T with R. wittichii RW1T and R. histidinilytica UM2T were 80.35 and 80.23â%, respectively, with digital DNA-DNA hybridization values of 23.6 and 22.9â%, respectively, and average amino acid identities of 75.59 and 75.79â%, respectively. The major isoprenoid quinone was Q-10, and the predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and sphingoglycolipid. Fatty acid methyl ether analysis showed that summed feature 8 (C18â:â1 ω7c and/or C18â:â1 ω6c) was the main cellular fatty acid in strain MK52T. Strain MK52T cells grew at 21-34 °C (optimum, 30 °C), pH 5-8 (optimum, pH 7) and with 0-2â% (w/v) NaCl (optimum, 0.5â% NaCl). Rhizorhabdus phycosphaerae sp. nov. is proposed as a new species (=KCTC 72877T=DSM 111424T) based on its genotypic and phenotypic characteristics.
