Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Sun, 10 Feb 2019 20:03:28 Shewanella sediminis sp. nov., a novel Na + -requiring and hexahydro-1,3,5-trinitro-1,3,5- triazine-degrading bacterium from marine sediment Jian-Shen Zhao, Dominic Manno, Chantale Beaulieu, Louise Paquet and Jalal Hawari Correspondence Jalal Hawari jalal.hawari@cnrc-nrc.gc.ca Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec, Canada H4P 2R2 Previously, a psychrophilic rod-shaped marine bacterium (strain HAW-EB3 T ) isolated from Halifax Harbour sediment was noted for its ability to degrade hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In the present study phenotypic, chemotaxonomic and genotypic characterization showed that strain HAW-EB3 T represents a novel species of Shewanella. Strain HAW-EB3 T contained lysine decarboxylase, which is absent in other known Shewanella species, and distinguished itself from most other species of Shewanella by the presence of arginine dehydrolase, ornithine decarboxylase and chitinase, and by its ability to oxidize and ferment N-acetyl-D-glucosamine. Strain HAW-EB3 T grew on several carbon sources (N-acetyl-D-glucosamine, Tween 40, Tween 80, acetate, succinate, butyrate and serine) and showed distinctive fatty acid and quinone compositions. Both phenotypic and 16S rRNA gene phylogenetic cluster analyses demonstrated that HAW-EB3 T belongs to the Na + -requiring group of Shewanella species. The HAW-EB3 T 16S rRNA gene sequence displayed ¡97?4 % similarity to all known Shewanella species and was most similar to those of two bioluminescent species, Shewanella hanedai and Shewanella woodyi. However, gyrB of strain HAW-EB3 T was significantly different from those of other Shewanella species, with similarities less than 85 %. DNA-DNA hybridization showed that its genomic DNA was less than 25 % related to that of S. hanedai or S. woodyi. Therefore we propose Shewanella sediminis sp. nov., with HAW-EB3 T (=NCIMB 14036 T =DSM 17055 T ) as the type strain. In a previous study several Shewanella strains capable of degrading hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were isolated from an unexploded-ordnance-dumping site (Emerald Basin, 215 m deep), 50 nautical miles from Halifax Harbour (Nova Scotia, Canada), Atlantic Ocean (Zhao et al., 2004a, b). In order to understand RDX metabolism and thus in situ biodegradation (natural attenuation) of the cyclic nitramine explosives at the Halifax site, phenotypic and genetic characterization of the isolates is necessary. Shewanella genus was proposed by MacDonell & Colwell (1985) for two bacteria previously classified as Alteromonas putrefaciens (Long & Hammer, 1941; Lee et al., 1977) and Alteromonas hanedai (Jensen et al., 1980), and one deep-sea barophilic isolate (Deming et al., 1984). Shewanella were defined as rod-shaped, Gram-negative, oxidase-positive, motile and chemo-organotrophic aquatic bacteria with 44–47 mol% G+C (MacDonell & Colwell, 1985). Since then many new species have been found, mostly from sea water, sediment and marine organisms, and currently there are 28 recognized Shewanella species (Shewanellaceae, ‘Alteromonadales’, class ‘Gammaproteobacteria’) at the time of writing this article (Bozal et al., 2002; Coyne et al., 1989; Bowman et al., 1997; Makemson et al., 1997; Nogi et al., 1998; Leonardo et al., 1999; Brettar et al., 2002; Ivanova et al., 2001, 2003a, b, 2004a, b, c; Skerratt et al., 2002; Satomi et al., 2003; Simidu et al., 1990; Toffin et al., 2004; Venkateswaran et al., 1998b; Yoon et al., 2004a, b; Ziemke et al., 1998). Some strains of Shewanella are known for polyunsaturated fatty acid production (Russell & Nichols, 1999; Bowman et al., 1997; Satomi et al., 2003), metal reduction (Myers & Published online ahead of print on 17 February 2005 as DOI 10.1099/ ijs.0.63604-0. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequence and the gyrB gene sequence of strain HAW-EB3 T are AY579750 and AY842130, respectively. A table of the quinone compositions of strain HAW-EB3 T and other species of Shewanella is available as supplementary material in IJSEM Online. Abbreviations: MK, menaquinone; MMK, methylmenaquinone; RDX, hexahydro-1,3,5-trinitro-1,3,5-triazine. 63604 G 2005 IUMS Printed in Great Britain 1511 International Journal of Systematic and Evolutionary Microbiology (2005), 55, 1511–1520 DOI 10.1099/ijs.0.63604-0