Citreicella manganoxidans sp. nov., a novel manganese oxidizing bacterium isolated from a shallow water hydrothermal vent in Espalamaca (Azores)

A Gram-stain negative, non-motile, non-spore forming, aerobic and rod or narrow lemon-shaped bacterial strain, VSW210T, was isolated from surface seawater in a shallow water hydrothermal vent region in Espalamaca (Azores). Strain VSW210T was found to grow optimally at 30 °C, at pH 7 and in the presence of 2–6 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain VSW210T clusters with the type strain Citreicellamarina CK-I3-6T (sequence similarity value of 99.6 %), but DNA–DNA hybridization showed DNA–DNA relatedness between the strain VSW210T and C. marina CK-I3-6T to be 55.8 ± 3.2 %. The DNA G+C content of strain VSW210T was determined to be 67.4 mol%. The cellular fatty acid profiles of strain VSW210T was found to contain C18:1ω7c (80.1 %) and C16:0 (9.2 %). The major polar lipids in strain VSW210T were identified as phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unidentified phospholipid. Strain VSW210T was found to be able to oxidize soluble Mn(II) to insoluble MnO2, which was confirmed with LBB staining. Differential phenotypic properties and genetic uniqueness revealed that this strain VSW210T is distinguishable from other species of the genus Citreicella. On the basis of the data presented, strain VSW210T is considered to represent a novel species of the genus Citreicella, for which the name Citreicella manganoxidans sp. nov. is proposed. The type strain is VSW210T (=KCTC 32497T = MCC 2286T).