Algisphaera agarilytica gen. nov., sp. nov., a novel representative of the class Phycisphaerae within the phylum Planctomycetes isolated from a marine alga.

A Gram-negative, strictly aerobic, reddish-pink pigmented, motile, spherical, agar-degrading bacterium designated 06SJR6-2(T) was isolated from a green coloured marine alga (Cladophora sp.). Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain was affiliated with the class Phycisphaerae and shared 89.2 % sequence similarity with Phycisphaera mikurensis FYK2301M01(T), which is the only validly named member of the class Phycisphaerae. The strain could be differentiated phenotypically from the recognised member of the class Phycisphaerae. The major fatty acids of strain 06SJR6-2(T) were identified as C16:0, C18:1ω9c and anteiso-C15:0. Amino acid analysis of cell wall hydrolysates indicated that the novel isolate did not contain diaminopimelic acid in the cell wall. The DNA G+C content of the strain was determined to be 63.0 mol% and the major respiratory quinone was identified as menaquinone 6 (MK-6). From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus in the family Phycisphaeraceae, for which the name Algisphaera agarilytica gen. nov., sp. nov. is proposed. The type strain of A. agarilytica is 06SJR6-2(T) (=KCTC 32482(T) = NBRC 109894(T)).