sp. nov., a Mn(II)-oxidizing bacterium isolated from heavy metal contaminated soils in Hunan Province, China.

A facultatively anaerobic, Gram-negative, rod-shaped bacterial strain designated as LLDRA6, was isolated from heavy metal contaminated soils collected near a ceased smelting factory at Zhuzhou, Hunan Province, China. Strain LLDRA6 has the ability to oxidize Mn(II) and generate biogenic manganese oxides. The strain can grow in a wide range of temperature from 10-42°C and pH from 5 to 10. Comparative analysis of its complete 16S rRNA gene sequence suggests that strain LLDRA6 is highly similar to species within the genus . The complete genome of LLDRA6 is 4 342 370 bp with 40.18 mol% of G+C content and contains no plasmids. In comparison to the genomes of type strains in , LLDRA6 shows average nucleotide identity values between 76.60 and 80.89 %, and digital DNA-DNA hybridization values in a range of 21.2-24.6 %. Both multilocus sequence analysis and genomic phylogenetics indicate a new taxonomic status for LLDRA6 in . Chemotaxonomic analyses for LLDRA6 show that the predominant cellular fatty acids are C, C and cyclo-C, accounting for 32.7, 16.1 and 10.3 % of total fatty acids, respectively. The polar lipids consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, four unidentified aminolipids, one unidentified phospholipid and three unidentified lipids. Within the cell wall, ribose and -diaminopimelic acid are the characteristic constituents for saccharides and amino acids, respectively. Respiratory quinones on cell membranes are composed of menaquinone (MK) and ubiquinone (coenzyme Q), including MK-8 (100.0 %), Q-7 (13.7 %) and Q-8 (86.3 %). Moreover, the positive results from d-lyxose and d-mannitol fermentation tests indicate that LLDRA6 is totally different from all the type strains within the genus . In summary, strain LLDRA6 represents a novel species in the genus , for which the name sp. nov. (type strain LLDRA6=CCTCC AB 2021154=KCTC 92091) is proposed.