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

ABSTRACT

A facultatively anaerobic, Gram-negative, rod-shaped bacterial strain designated as LLDRA6T, was isolated from heavy metal contaminated soils collected near a ceased smelting factory at Zhuzhou, Hunan Province, China. Strain LLDRA6T 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 LLDRA6T is highly similar to species within the genus Providencia. The complete genome of LLDRA6T 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 Providencia, LLDRA6T 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 LLDRA6T in Providencia. Chemotaxonomic analyses for LLDRA6T show that the predominant cellular fatty acids are C16  0, C14  0 and cyclo-C17  0, 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 meso-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 LLDRA6T is totally different from all the type strains within the genus Providencia. In summary, strain LLDRA6T represents a novel species in the genus Providencia, for which the name Providencia manganoxydans sp. nov. (type strain LLDRA6T=CCTCC AB 2021154T=KCTC 92091T) is proposed.