Flavihumibacter stibioxidans sp. nov., an antimony-oxidizing bacterium isolated from antimony mine soil

A Gram-stain-positive, strictly aerobic, non-motile and rod-shaped bacterial strain, designated YS-17T, was isolated from soil in the Lengshuijiang antimony mine, Hunan Province, China. Comparative 16S rRNA gene sequencing analysis clustered it with Flavihumibacter strains, and strain YS-17T was most closely related to Flavihumibacter cheonanensis WS16T (97.2 % similarity), Flavihumibacter petaseus T41T (96.6 %) and Flavihumibacter solisilvae 3-3T (96.5 %). The level of DNA-DNA relatedness between strain YS-17T and F. cheonanensis JCM 19322T was 35.5±0.1 % (n=2). The major respiratory quinone of strain YS-17T was menaquinone-7 and the major polar lipids were phosphatidylethanolamine, two unidentified lipids, two unidentified amino lipids and phospholipid. The major fatty acids (≥5 %) were iso-C15 : 0, iso-C15 : 1 G, unknown ECL 13.565, iso-C17 : 0 3-OH, C15 : 0, C16 : 1ω5c and anteiso-C15 : 0. The DNA G+C content was 47.8 mol%. Compared with other Flavihumibacter strains, strain YS-17T showed major biophysical and biochemical differences, with the ability to hydrolyse gelatin and to assimilate salicin and l-proline. The results demonstrated that strain YS-17T belongs to the genus Flavihumibacter and represents a novel species, for which the name Flavihumibacter stibioxidans sp. nov. is proposed. The type strain is YS-17T (=CCTCC AB 2016053T=KCTC 52205T).