Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Tue, 11 Dec 2018 07:08:24 Alteromonas pelagimontana sp. nov., a marine exopolysaccharide-producing bacterium isolated from the Southwest Indian Ridge Rupesh Kumar Sinha, K. P. Krishnan,* Archana Singh, Femi Anna Thomas, Anand Jain and P. John Kurian Abstract A novel exopolysaccharide-producing strain, designated as 5.12 T , was isolated from a sediment sample from the Southwest Indian Ridge, Indian Ocean. The strain was Gram-stain-negative, motile, strictly aerobic, and oxidase- and catalase-positive. It grew optimally at 35  C, at pH 6.0 and in the presence of 3.5 % (w/v) NaCl. Its major isoprenoid quinone was ubiquinone-8 (Q-8) and summed feature 3 (comprising C 16 : 1 !6c and/or C 16 : 1 !7c), C 16 : 0 and C 18 : 1 !7c were the major cellular fatty acids. The DNA G+C content was 46.1 mol%. 16S rRNA gene sequence analysis suggested that strain 5.12 T is a member of the genus Alteromonas. Strain 5.12 T exhibited close 16S rRNA gene sequence similarity to Alteromonas lipolytica JW12 T (96.1 %), Alteromonas hispanica F-32 T (95.9 %), Alteromonas confluentis DSSK2-12 T (95.9 %), Alteromonas litorea TF-22 T (95.6 %) and Alteromonas mediterranea DE T (95.5 %). Strain 5.12 T contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. Owing to significant differences in the 16S rRNA gene sequences, as well as the phenotypic and chemotaxonomic characteristics, the novel isolate described here merits classification as a representative of a novel species of the genus Alteromonas, for which the name Alteromonas pelagimontana sp. nov. is proposed. The type strain of this species is 5.12 T (LMG 29661 T = MCC 3250 T ). The genus Alteromonas, a member of the class Gammapro- teobacteria, was proposed by Baumann et al. [1] with the descriptions of four species of the genus Alteromonas including Alteromonas macleodii as the type species [1]. At the time of writing, the genus Alteromonas comprises 16 species with validly published names [2]. Members of the genus Alteromonas have been isolated from a variety of marine environments and marine organisms [1–14]. In the present study, we describe a bacterial strain, designated as 5.12 T , which was isolated from the Southwest Indian Ridge. Comparative 16S rRNA gene sequence analysis indicated that strain 5.12 T is phylogenetically most closely affiliated to the genus Alteromonas with the closest type strain being Alteromonas lipolytica JW12 T (96.1 %). The aim of the pres- ent study was to determine the exact taxonomic position of strain 5.12 T by using a polyphasic characterization that included the determination of the chemotaxonomic and other phenotypic properties and a detailed phylogenetic investigation. A sediment sample was collected from a ridge wall of the Southwest Indian Ridge (26  56.49¢ S 67  19.47¢ E) located in the Indian Ocean, and was used as a source for the isolation of bacterial strains. The retrievability of heterotrophic bac- teria was assessed in different concentrations (10, 25, 50, 75 and 100 %, w/v) of Zobell marine agar 2216 (HiMedia) at 4  C. Maximum retrievability and morphological diversity was observed in quarter strength (25 % w/v) medium; hence this concentration was used for further isolation and routine culturing. Strain 5.12 T was isolated by the standard dilution plating technique at 4  C on quarter strength Zobell marine agar (qsZMA) 2216 [full strength (100 % w/v)=55.25 g ZMA l 1 distilled water]. The reference strain, A. lipolytica JW12 T , was obtained from Dr Xue-Wei Xu, Second Institute of Oceanography, SOA, Hangzhou, PR China. The phenotypic and chemotaxonomic characteristics of strain 5.12 T and reference strain JW12 T were determined under the same experimental conditions. The cell morphol- ogy, Gram reaction, pH range for growth, ability to grow anaerobically, requirement for NaCl, hydrolysis of various carbon sources and susceptibility to antibiotics were deter- mined as described by Park et al. [10]. Growth at 5–45  C, with 5  C intervals, was measured on quarter strength Zobell marine broth (qsZMB) 2216 (HiMedia; full strength=40.25 g ZMB l 1 distilled water) to determine the optimal Author affiliation: National Centre for Antarctic and Ocean Research, Headland Sada, Vasco da Gama, Goa, India. *Correspondence: K. P. Krishnan, kpkrishnan@gmail.com Keywords: Alteromonas; exopolysaccharide; deep sea sediment; Southwest Indian Ridge. Abbreviations: AFM, Atomic Force Microscopy; EPS, Exopolysaccharide. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain 5.12 T is LT593862. Six supplementary figures are available with the online Supplementary Material. TAXONOMIC DESCRIPTION Sinha et al., Int J Syst Evol Microbiol 2017;67:4032–4038 DOI 10.1099/ijsem.0.002245 002245 ã 2017 IUMS 4032