sp. nov., an obligately chemolithoautotrophic, hydrogen-oxidizing bacterium isolated from coastal marine sediments.

A novel mesophilic, chemolithoautotrophic, hydrogen-oxidizing bacterium, designated strain ST1-3, was isolated from mud sediment samples collected from mangroves in Jiulong River estuary. The cells were Gram-stain-negative, non-motile and rod-shaped. The temperature, pH and salinity ranges for growth of strain ST1-3 were 4-45 °C (optimum, 35 °C), pH 5.0-8.5 (optimum, pH 7.0) and 0-8.0 % (w/v) NaCl (optimum, 4.0 %). The isolate was an obligate chemolithoautotroph capable of growth using hydrogen as the only energy source, and molecular oxygen, thiosulphate and elemental sulphur as electron acceptors. The major cellular fatty acids of strain ST1-3 were summed feature 3 (C 7 and/or C 6), C and summed feature 8 (C 7). The major polar lipids were phosphatidylethanolamine, phosphatidyldimethyl ethanolamine and phosphatidylglycerol. The respiratory quinone was menaquinone-6. The genomic DNA G+C content was 43.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and core genes showed that the novel isolate belonged to the genus and was most closely related to 42BKT (94.7 % sequence identity). The average nucleotide identity and digital DNA-DNA hybridization values between ST1-3 and 42BKT were 74.6 and 16.3 %, respectively. On the basis of the phenotypic, phylogenetic and genomic data presented here, strain ST1-3 represents a novel species of the genus , for which the name sp. nov. is proposed, with the type strain ST1-3 (=MCCC M25234=KCTC 25639).