Runella limosa sp. nov., isolated from activated sludge

Abstract

A Gram-negative bacterium, designated strain EMB111T, 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 EMB111T were iso-C15:0, C16:1ω5c, iso-C17:0 3-OH, iso-C15:0 3-OH, C16:0 3-OH, C16:0 and summed feature 3 (C16:1ω7c and/ or iso-C15:0 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 EMB111T formed a phyletic cluster with members of the genus Runella within the family Flexibacteraceae and was most closely related to Runella slithytormis ATCC 29530T with a 16S rRNA gene sequence similarity of 94.8%. On the basis of chemotaxonomic data and molecular properties, strain EMB111T represents a novel species within the genus Runella, for which the name Runelly limosa sp. nov. is proposed. The type strain is EMB111T (=KCTC 12615T=DSM 17973T).