Halolactibacillus halophilus gen. nov., sp. nov. and Halolactibacillus miurensis sp. nov., halophilic and alkaliphilic marine lactic acid bacteria constituting a phylogenetic lineage in Bacillus rRNA group 1

Department of Fermentation Science, Faculty of Applied Bio-Science, Tokyo University of Agriculture, 1-1 Sakuragaoka 1-chome, Setagaya-ku, Tokyo 156-8502, Japan Correspondence Morio Ishikawa m1ishika{at}nodai.ac.jp Eleven novel strains of marine-inhabiting lactic acid bacteria that were isolated from living and decaying marine organisms collected from a temperate area of Japan are described. The isolates were motile with peritrichous flagella and non-sporulating. They lacked catalase, quinones and cytochromes. Fermentation products from glucose were lactate, formate, acetate and ethanol. Lactate yield as percentage conversion from glucose was affected by the pH of the fermentation medium: 55 % at the optimal growth pH of 8·0, greater than 70 % at pH 7·0 and less than 30 % at pH 9·0. The molar ratio of the other three products was the same at each cultivation pH, approximately 2 : 1 : 1. Carbohydrates and related compounds were aerobically metabolized to acetate and pyruvate as well as lactate. The isolates were slightly halophilic, highly halotolerant and alkaliphilic. The optimum NaCl concentration for growth was 2·0–3·0 % (w/v), with a range of 0–25·5 %. The optimum pH for growth was 8·0–9·5, with a range of 6·0–10·0. The G+C content of the DNA was 38·5–40·7 mol%. The isolates constituted two genomic species (DNA–DNA relatedness of less than 41 %) each characterized by sugar fermentation profiles. The cell-wall peptidoglycan of both phenotypes contained meso -diaminopimelic acid. The major cellular fatty acids were C 16 : 0 and a-C 13 : 0 . Comparative sequence analysis of the 16S rRNA genes revealed that these isolates represent novel species constituting a phylogenetic unit outside the radiation of typical lactic acid bacteria and an independent line of descent within the group composed of the halophilic/halotolerant/alkaliphilic and/or alkalitolerant species in Bacillus rRNA group 1, with 94·8–95·1 % similarity to the genus Paraliobacillus , 93·7–94·1 % to the genus Gracilibacillus and 93·8–94·2 % to Virgibacillus marismortui . On the basis of possession of physiological and biochemical characteristics common to typical lactic acid bacteria within Bacillus rRNA group 1, chemotaxonomic characteristics and phylogenetic independence, a new genus and two species, Halolactibacillus halophilus gen. nov., sp. nov. and Halolatibacillus miurensis sp. nov., are proposed. The type strains are Halolactibacillus halophilus M2-2 T (=DSM 17073 T =IAM 15242 T =NBRC 1