Unique gel-like colony forming bacterium Novosphingobium pituita sp. nov., isolated from a membrane bioreactor (MBR) treating sewage

A novel, gelatinous, colony-forming, rod-shaped bacterial strain, designated IK01^T was isolated from biofilms formed on the membrane surface of a sewage-treating membrane bioreactor (MBR). Strain IK01^T produced gelatinous and almost transparent colonies at lower medium concentrations. Fourier transform infrared analysis of the gelatinous colony matrix showed that the matrix could be a biofilm substance. This suggests that strain IK01^T is a fouling-causing bacteria in the MBR. Furthermore, 16S rRNA gene sequence analysis showed that strain IK01^T was phylogenetically placed in the genus Novosphingobium. The average nucleotide identity values for IK01^T and the other 50 species of the genus Novosphingobium ranged from 78.5 to 83.9 %. Correspondingly, the estimated digital DNA-DNA hybridization values ranged from 20.8 to 24.4 %. The genomic DNA G + C content was 66.0 %. The predominant fatty acids were summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c), summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), and C_14:0 2-OH. A polar lipid profile revealed phosphatidylethanolamine, two unidentified phospholipids, and three aminoglycophospholipids as major compounds. The major respiratory quinone was ubiquinone Q-10. Genotypic, chemotaxonomic, and phenotypic analyses characterized the newly identified strain IK01^T, as a novel species of the genus Novosphingobium, for which we propose the name Novosphingobium pituita sp. nov. The type strain is IK01^T (NBRC 116408^T = DSM 116658^T).