Dehalogenimonas loeffleri sp. nov., a halotolerant organohalide-respiring bacterium isolated from estuarine sediments capable of dechlorinating and debrominating multiple halogenated alkanes

A novel obligate anaerobic mesophilic bacterium, strain WT, was isolated from River Wuli estuary sediments (Liaoning, China). Cells were Gram-stain-negative, non-spore-forming, non-motile, irregular cocci (0.4-0.8 µm in diameter). Strain WT couples growth with the reductive dehalogenation of various polychlorinated and polybrominated alkanes, producing ethene from 1,2-dibromoethane and 1,2-dichloroethane, propene from 1,2-dibromopropane and 1,2-dichloropropane, a mixture of cis- and trans-1,2-dichloroethene from 1,1,2,2-tetrachloroethane, vinyl chloride from 1,1,2-trichloroethane and allyl chloride from 1,2,3-trichloropropane. The strain grows optimally at 25-30 °C, pH 7.2-7.5, and with 0.1-2.1% (w/v) NaCl, but did not grow in the presence of oxygen. Both formate and H₂ served as electron donors for organohalide respiration with acetate as carbon source. Major cellular fatty acids were C16 : 0, C18 : 1 ω9c, C14 : 0 and C16 : 1 ω9c. The 1.77 Mb genome had a G+C content of 52.50 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain WT was affiliated with the genus Dehalogenimonas of the class Dehalococcoidia and most closely related to Dehalogenimonas lykanthroporepellens (97.7% sequence identity). Genome-wide comparison of average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values demonstrated that strain WT represents a distinct species. Based on phylogenomic analysis and phenotypic features, strain WT is classified as a novel species within the genus Dehalogenimonas, for which the name Dehalogenimonas loeffleri sp. nov. is proposed. The type strain is WT (=CGMCC 40791T=KCTC 25953T).