Runella limosa sp. nov., isolated from activated sludge

A Gram-negative bacterium, designated strain EMB111^T, was isolated from activated sludge performing enhanced biological phosphorus removal in a sequencing batch reactor. Cells were long and rod-shaped. The isolate was strictly aerobic and non-motile. The strain grew optimally at 25-30°C and pH 7.5-8.0. The predominant fatty acids of strain EMB111^T were iso-C_15:0, C_16:1ω5c, iso-C_17:0 3-OH, iso-C_15:0 3-OH, C_16:0 3-OH, C_16:0 and summed feature 3 (C_16:1ω7c and/ or iso-C_15:0 2-OH). The strain contained a large amount of phosphatidylglycerol and small amounts of two unknown phospholipids (PL1, PL2) as the polar lipids. The major isoprenoid quinone was menaquinone-7. The G+C content of the genomic DNA was 42.7 mol%. Phylogenetic analysis showed that strain EMB111^T formed a phyletic cluster with members of the genus Runella within the family Flexibacteraceae and was most closely related to Runella slithytormis ATCC 29530^T with a 16S rRNA gene sequence similarity of 94.8%. On the basis of chemotaxonomic data and molecular properties, strain EMB111^T represents a novel species within the genus Runella, for which the name Runelly limosa sp. nov. is proposed. The type strain is EMB111^T (=KCTC 12615^T=DSM 17973^T).