Tetragenococcus muriaticus sp. nov., a new moderately halophilic lactic acid bacterium isolated from fermented squid liver sauce
International Journal of Systematic Bacteriology
A total of 11 strains of moderately halophilic histamine-producing bacteria isolated from fermented squid liver sauce were studied phenotypically, genotypically, and phylogenetically. These strains are considered members of the genus Tetragenococcus based on their physiological, morphological, and chemotaxonomic characteristics. A 16S rRNA gene sequence analysis showed that these strains clustered with, but were separate from, Tetragenococcus halophilus. The results of DNA-DNA hybridization
... riments indicated that the new isolates represent a new Tetragenococcus species, for which we propose the name Tetragenococcus muriaticus; strain X-1 ؍( JCM 10006) is the type strain of this species. Pediococcus halophilus was described as a halophilic lactic acid bacterium which requires sodium chloride (NaCl) for growth and is tolerant of a high NaCl concentration (more than 18%). According to Bergey's Manual of Systematic Bacteriology (6), tetrad cocci which are tolerant of 18% NaCl are members of P. halophilus. Recently, however, Collins et al. (4) reported that P. halophilus is phylogenetically more closely related to enterococci and lactobacilli than to pediococci on the basis of 16S 16S rRNA sequence data, and thus they proposed that P. halophilus should be reclassified in a new genus, the genus Tetragenococcus, with Tetragenococcus halophilus as the single species recognized in the genus (2). Previous workers have isolated large numbers of T. halophilus as the predominant bacteria (7, 8) from Shottsuru, a Japanese local traditional fermented fish sauce, which contains more than 25% NaCl. In this study, we isolated histamineproducing lactic acid bacteria from Shottsuru-like squid liver sauce. Eleven strains were designated strains X-1 T to X-11 and were different from authentic T. halophilus strains in the following characteristics: production of histamine, lack of L-arabinose fermentation, growth at 40°C, and 16S rRNA gene (rDNA) sequence. To precisely identify and phylogenetically place the new isolates, phenotypic characterization, analysis of fatty acid compositions, 16S rDNA sequencing, and DNA-DNA hybridization were performed. On the basis of our results we propose that our isolates should be placed in a new species, Tetragenococcus muriaticus.