Pusillimonas thiosulfatoxidans sp. nov., a thiosulfate oxidizer isolated from activated sludge.

A Gram-stain-negative, motile bacterium, designated strain YE3, was isolated from activated sludge obtained from a municipal wastewater treatment plant in Daejeon Metropolitan City, Republic of Korea. The cells were oxidase- and catalase-positive, and grew under aerobic conditions at 10-40 °C (optimum, 30 °C), with 1.0-8.0 % (w/v) NaCl (1.0 %) and at pH 5.5-9.0 (pH 7.0). Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain YE3 was most closely related to Pusillimonasharenae KACC 14927 (98.2 % sequence similarity) and Pusillimonasginsengisoli KCTC 22046 (98.0 %). DNA-DNA relatedness values for strain YE3 and P. harenae KACC 14927, P. ginsengisoli KCTC 22046 and P. soli KCTC 22455 were 28.7±2.27 %, 21.3±1.16 %, and 14.0±0.67 %, respectively. The genomic G+C content of the type strain YE3 was 59.3 mol%, as determined by whole-genome sequencing. The dominant fatty acids were C16 : 0 (39.2 %) and C17 : 0cyclo (37.5 %). The major polar lipids of strain YE3 were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Two aminophospholipids and four unidentified lipids were also detected. Furthermore, strain YE3 was able to oxidize thiosulfate under heterotrophic conditions. Based on the phenotypic, genotypic, chemotaxonomic and phylogenetic analyses, strain YE3 represents a novel species of the genus Pusillimonas, for which the name Pusillimonas thiosulfatoxidans sp. nov. is proposed. The type strain is YE3 (=KCTC 62737=NBRC 113113).