Oceanobacillus oncorhynchi subsp. incaldanensis subsp. nov., an alkalitolerant halophile isolated from an algal mat collected from a sulfurous spring in Campania (Italy), and emended description of Oceanobacillus oncorhynchi

Abstract

A halophilic, alkalitolerant bacterium, strain 20AGT, was isolated from an algal mat collected from a sulfurous spring located in Santa Maria Incaldana (Mondragone, Campania Region, southern Italy). The isolate is Gram-positive, ferments several carbohydrates and has motile, rod-shaped cells that do not sporulate. The isolate grows at pH 6·5–9·5 and in 5–20 % NaCl. On the basis of 16S rRNA gene sequence similarity, the strain was shown to belong to the genus Oceanobacillus; strain 20AGT showed 96·6 % 16S rRNA gene sequence similarity to the type strain of Oceanobacillus iheyensis, DSM 14371T, and 99·5 % similarity to Oceanobacillus oncorhynchi NCIMB 14022T. Levels of DNA–DNA relatedness between strain 20AGT and O. iheyensis DSM 14371T and O. oncorhynchi NCIMB 14022T were respectively 29·4 and 59·0 %. The G+C content of the DNA of strain 20AGT was 40·1 mol%. The predominant respiratory quinone was MK-7, phosphatidylglycerol and phosphatidylcholine were the predominant polar lipids and minor phospholipids were also detected. ai-C14 : 0, ai-C15 : 0 and i-C15 : 0 were the major fatty acids. Strain 20AGT accumulated osmolytes and produced exopolysaccharide. On the basis of phenotypic characteristics, phylogenetic data and DNA–DNA relatedness data, isolate 20AGT should be designated as the type strain of a subspecies of Oceanobacillus oncorhynchi, for which the name Oceanobacillus oncorhynchi subsp incaldanensis subsp. nov. is proposed. The type strain is 20AGT (=DSM 16557T=ATCC BAA-954T).