Characterization of Salinivibrio socompensis sp. nov., A New Halophilic Bacterium Isolated from the High-Altitude Hypersaline Lake Socompa, Argentina.

Cristina Galisteo,Cristina Sánchez-Porro,María E Farias,Antonio Ventosa,Rafael R De La Haba,Clara López-Hermoso,Ana B Fernández

doi:10.3390/microorganisms7080241

Abstract

The genus Salinivibrio belongs to the family Vibrionaceae and includes Gram-stain-negative, motile by a polar flagellum, and facultatively anaerobic curved rods. They are halophilic bacteria commonly found in hypersaline aquatic habitats and salted foods. This genus includes five species and two subspecies. A presumed novel species, strain S35T, was previously isolated from the high-altitude volcanic, alkaline, and saline lake Socompa (Argentinean Andes). In this study we carried out a complete taxonomic characterization of strain S35T, including the 16S rRNA gene sequence and core-genome analysis, the average nucleotide identity (ANIb, ANIm, and orthoANI), and in silico DNA–DNA hybridization (GGDC), as well as the phenotypic and chemotaxonomic characterization. It grew at 3%–20% (w/v) NaCl, pH 6–10, and 10–42 °C, with optimum growth at 7.0%–7.5% (w/v) NaCl, pH 8.0, and 37 °C, respectively. Strain S35T was oxidase- and catalase-positive, able to produce acid from D-glucose and other carbohydrates. Hydrolysis of DNA, methyl red test, and nitrate and nitrite reduction were positive. Its main fatty acids were C16:0, C16:1 ω7c and C16:1 ω6c, and C18:1 ω7c and/or C18:1 ω6c. ANI, GGDC, and core-genome analysis determined that strain S35T constitutes a novel species of the genus Salinivibrio, for which the name Salinivibrio socompensis sp. nov. is proposed. The type strain is S35T (= CECT 9634T = BNM 0535T).

Highlights

The two main groups that inhabit hypersaline environments are the extremely halophilic archaea and the moderately halophilic bacteria [1,2]
We show that strain S35T constitutes a new species for which we propose the designation of Salinivibrio socompensis sp. nov
The 16S rRNA gene sequence comparative analysis of strain S35T with respect to the type strains of S. costicola subsp. costicola CECT 4059T, S. costicola subsp. alcaliphilus DSM 16359T, S. proteolyticus DSM 19052T, S. siamensis JCM 14472T, S. sharmensis DSM 18182T, and S. kushneri AL184T showed percentages of similarity of 99.2%, 99.4%, 97.7%, 97.7%, 97.9%, and 98.9%, respectively. These high percentages indicate that strain S35T is a member of the genus Salinivibrio, but they are not conclusive to determinate if strain S35T may constitute a novel species

Summary

Introduction

The two main groups that inhabit hypersaline environments are the extremely halophilic archaea ( called haloarchaea) and the moderately halophilic bacteria [1,2]. The haloarchaea are classified within the class Halobacteria with three orders: Haloferacales, Halobacteriales, and Natrialbales [3]. Halophilic microorganisms have an important biotechnological potential due to their exceptional physiological and biochemical characteristics. Among their most interesting applications are found the production of a novel restriction enzyme [4], agarases, with industrial and medical applications [5], or β-galactosidase, to produce lactose-free dairy products [6]. Other applications include the production of ectoines, polysaccharides, or extracellular enzymes [1]

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