Runella limosa sp. nov., isolated from activated sludge

Abstract

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 degrees C and pH 7.5-8.0. The predominant fatty acids of strain EMB111(T) were iso-C(15 : 0), C(16 : 1)omega5c, 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 : 1)omega7c 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 slithyformis 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 Runella limosa sp. nov. is proposed. The type strain is EMB111(T) (=KCTC 12615(T)=DSM 17973(T)).