Characterisation of a newly isolated member of a candidatus lineage, marispirochaeta aestuarii gen. Nov., sp. nov

Abstract

Metagenome analysis of coastal marine habitats of Gujarat, India indicated the presence of twelve novel putative lineages of spirochaetes. Out of which a strain designated JC444T representing a novel putative lineage seven was isolated and characterized based on a polyphasic taxonomic approach. Strain JC444Twas helical, Gram-stain-negative, obligate anaerobe, catalase and oxidase negative. Strain JC444T was able to grow at 15-45 °C (optimum at 30-35 °C), pH 6.5-8.6 (optimum at 7.5-8.0) and 0.6-5 % (optimum at 1.5-2.0 %) of NaCl concentration. The major end products of glucose fermentation were acetate, formate, hydrogen and carbon dioxide. C14 : 0, iso-C15 : 0, C16 : 0, C18 : 0, iso-C15 : 1H/C13 : 03OH (summed feature 1), iso-C13 : 0, anteiso-C15 : 0and iso-C17 : 0were present as fatty acids. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and unidentified lipids (L1-4) were the polar lipids. G+C mol% of strain JC444Twas 53.6 %. 16S rRNA gene sequence comparisons indicated that strain JC444Trepresents a member of the family Spirochaetaceae in the order Spirochaetales. Strain JC444Thas a sequence similarity of 97.1 % with ’Candidatus Marispirochaeta associata’ JC231 and < 90.1 % with other members of the family Spirochaetaceae. Distinct morphological, physiological and genotypic differences from the previously described taxa support the classification of strain JC444Tas a representative of a new genus and species in the family Spirochaetaceae, for which the name Marispirochaeta aestuarii gen. nov., sp. nov. is proposed. Type strain is JC444T(=KCTC 15554T=DSM 103365T).