Polyphasic taxonomic characterisation of a novel strain as Pararhizobium haloflavum sp. nov., isolated from soil samples near a sewage treatment tank.

A Gram-stain negative, aerobic, motile and ovoid- to rod-shaped bacteria strain, designated XC0140T, was isolated from soil samples near the sewage treatment tank of a chemical factory in Zhejiang Province, China, and subjected to polyphasic taxonomic investigation. Strain XC0140T grew at 10-37 °C and pH 6.0-9.0 (optimum, 35 °C and pH 7.5) and with 0-17% (w/v) NaCl (optimum, 1%). According to phylogenetic analysis based on 16S rRNA gene sequences, strain XC0140T was assigned to the genus Pararhizobium with high 16S rRNA gene sequence similarity of 95.97% to "Pararhizobium helanshanense CCNWQTX14T", followed by Pararhizobium sphaerophysae CCNWGS0238T (95.95%). Chemotaxonomic analysis showed that strain XC0140T contains ubiquinone-10 as the predominant respiratory quinone and possessed summed feature 8 (comprising C18: 1 ω7c and/or ω6c), 11-methyl C18:1 ω7c, C18: 0 and C16: 0 as predominant forms of fatty acids. The polar lipids of strain XC0140T consisted of seven phospholipids (PL), two aminolipids (AL), one glycolipid (GL) and three unidentified lipids (L1, L2 and L3). The DNA G+C content was 62.7 mol%. Based on the polyphasic taxonomic characterization, strain XC0140T is considered to represent a novel species of the genus Pararhizobium, for which the name Pararhizobium haloflavum sp. nov. is proposed. (type strain XC0140T = MCCC 1K03228T = KCTC 52582T).