Mangroviflexus xiamenensis gen. nov., sp. nov., a member of the family Marinilabiliaceae isolated from mangrove sediment

Abstract

A Gram-negative, obligately anaerobic, non-spore-forming, long rod-shaped bacterium strain P2Twas isolated from the offshore mangrove sediment of the South China Sea. Growth was observed at between 22 and 39 °C, with an optimum at 35 °C. The pH range for growth was 5.0–8.5, with an optimum around pH 7.0–7.5. Salt tolerance was determined between 0.2 and 3.5 % (w/v), optimum at 0.5–1.0 %. Catalase and oxidase activities were negative. Strain P2Tutilized cysteine, lactate, pyruvate, yeast extract or H2/CO2+acetate as electron donors, and sulfate or sulfite as electron acceptors. Metabolism was strictly fermentative. The main organic fermentation products were propionate, acetate and succinate. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain P2Tformed a distinct evolutionary lineage within the familyMarinilabiliaceae. Strain P2Twas most closely related to members of the generaAlkaliflexus(92.0 % 16S rRNA gene sequence similarity),Marinilabilia(91.7 %) andAnaerophaga(89.9 %) of the familyMarinilabiliaceae. The DNA G+C content of the novel strain was 44.2±1.0 mol%. The dominant fatty acids of strain P2Twere iso-C15 : 0(33.5 %), anteiso-C15 : 0(18.9 %), C16 : 0(5.4 %), C16 : 03-OH (7.7 %) and iso-C17 : 03-OH (13.3 %). The respiratory quinone was menaquinone 7 (100 % of total quinone) and the major polar lipid was phosphatidylethanolamine. Strain P2Twas distinguishable from members of phylogenetically related genera by differences in several phenotypic properties. On the basis of phylogenetic, phenotypic and physiological evidence, a novel genus,Mangroviflexus, is proposed to harbour strain P2T( = CGMCC 1.5167T = DSM 24214T) which is described as the type strain of a novel species,Mangroviflexus xiamenensisgen. nov., sp. nov.