Ferrimonas sediminicola sp. nov. and Ferrimonas aestuarii sp. nov., Fe(III)-reducing bacteria isolated from marine environments

Abstract

Two Gram-stain-negative, Fe(III)-reducing, facultatively anaerobic, motile via a single polar flagellum, rod-shaped bacterial strains, designated IMCC35001^T and IMCC35002^T, were isolated from tidal flat sediment and seawater, respectively. Results of 16S rRNA gene sequence analysis showed that IMCC35001^T and IMCC35002^T shared 96.6 % sequence similarity and were most closely related to Ferrimonas futtsuensis FUT3661^T (98.6 %) and Ferrimonas kyonanensis Asr22-7^T (96.8 %), respectively. Draft genome sequences of IMCC35001^T and IMCC35002^T revealed 4.0 and 4.8 Mbp of genome size with 61.0 and 51.8 mol% of DNA G+C content, respectively. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 73.1 and 19.8 %, respectively, indicating that they are separate species. The two genomes showed ≤84.4 % ANI and ≤27.8 % dDDH to other species of the genus Ferrimonas, suggesting that the two strains each represent novel species. The two strains contained both menaquinone (MK-7) and ubiquinones (Q-7 and Q-8). Major fatty acids of strain IMCC35001^T were iso-C_{15 : 0}, C_{18 : 1} ω9c, C_{17 : 1} ω8c and C_{16 : 0} and those of strain IMCC35002 ^T were C_{18 : 1} ω9c, C_{16 : 0} and summed feature 3 (C_{16 : 1} ω7c and/or C_{16 : 1} ω6c). Major polar lipids in both strains were phosphatidylethanolamine, phosphatidylglycerol, unidentified phospholipid, unidentified aminophospholipid and unidentified lipids. The two strains reduced Fe(III) citrate, Fe(III) oxyhydroxide, Mn(IV) oxide and sodium selenate but did not reduce sodium sulfate. They were also differentiated by several phenotypic characteristics. Based on the polyphasic taxonomic data, IMCC35001^T and IMCC35002^T were considered to represent each novel species in the genus Ferrimonas, for which the names Ferrimonas sediminicola sp. nov. (IMCC35001^T=KACC 21161^T=NBRC 113699^T) and Ferrimonas aestuarii (IMCC35002^T=KACC 21162^T=NBRC 113700^T) sp. nov. are proposed.

Keywords: Ferrimomas sediminicola; Ferrimonas; Ferrimonas aestuarii; iron-reducing bacteria; marine bacteria; taxonomy.