Limnobacter parvus sp. nov., a Thiosulfate-Oxidizing Bacterium Isolated from Lake Water

A novel bacterium, designated as strain YS8-69^T, was isolated from an inland closed lake, Xinjiang Uygur Autonomous Region, PR China. Comparative analysis of the 16S rRNA gene sequence shows the strain was affiliated to the genus Limnobacter, in the family Burkholderiaceae, with the highest similarities to Limnobacter alexandrii LZ-4^T (98.93%), Limnobacter thiooxidans DSM 13612^T (98.55%), Limnobacter humi NBRC 111650^T (97.66%), and Limnobacter litoralis KP1-19^T (97.04%). Strain YS8-69^T was a Gram stain-negative, strictly aerobic, rod shaped, catalase- and oxidase-positive bacterium, and growth was observed at 4-40 °C (optimum, 25 °C), pH 7.0-10.0 (optimum, pH 7.0), and 0-3% (w/v) NaCl (optimum, 0.5%). The principal fatty acids were C_16:0, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The sole respiratory quinone was Q-8 and total polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), an unidentified aminolipid (AL), two unidentified glycolipids (GL1,2), an unidentified amino phosphoglycolipid (APGL), two unidentified phospholipids (PL1,2), two unidentified aminophospholipids (APL1,2), and three unidentified lipids (L1,2,3). The average nucleotide identity (ANI) values and in silico DDH between strain YS8-69^T and L. alexandrii LZ-4^T, L. thiooxidans JCM 13612^T, and L. humi DSM 111650^T were 73.0-80.6% and 15.8-50.2%, respectively. The genome sequence showed a length of 3,162,663 bp, with 20 contigs and 51.7% of G + C content. Based on physiological, chemotaxonomic, genotypic characteristics, and phylogenetic results, we propose that strain YS8-69^T represents a novel specie of the genus Limnobacter, for which the name Limnobacter parvus sp. nov. is proposed (type strain YS8-69^T = MCCC 1K08015^T = KCTC 92278^T).