Description of Gramella forsetii sp. nov., a marine Flavobacteriaceae isolated from North Sea water, and emended description of Gramella gaetbulicola Cho et al. 2011.

Strain KT0803T was isolated from coastal eutrophic surface waters of Helgoland Roads near the island of Helgoland, North Sea, Germany. The taxonomic position of the strain, previously known as 'Gramella forsetii' KT0803, was investigated by using a polyphasic approach. The strain was Gram-stain-negative, chemo-organotrophic, heterotrophic, strictly aerobic, oxidase- and catalase-positive, rod-shaped, motile by gliding and had orange-yellow carotenoid pigments, but was negative for flexirubin-type pigments. It grew optimally at 22-25 °C, at pH 7.5 and at a salinity between 2-3 %. Strain KT0803T hydrolysed the polysaccharides laminarin, alginate, pachyman and starch. The respiratory quinone was MK-6. Polar lipids comprised phosphatidylethanolamine, six unidentified lipids and two unidentified aminolipids. The predominant fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 1ω7c and iso-C17 : 1ω7c, with smaller amounts of iso-C15 : 0 2-OH, C15 : 0, anteiso-C15 : 0 and C17 : 1ω6c. The G+C content of the genomic DNA was 36.6 mol%. The 16S rRNA gene sequence identities were 98.6 % with Gramella echinicola DSM 19838T, 98.3 % with Gramella gaetbulicola DSM 23082T, 98.1 % with Gramella aestuariivivens BG-MY13T and Gramella aquimixticola HJM-19T, 98.0 % with Gramella lutea YJ019T, 97.9 % with Gramella portivictoriae DSM 23547T and 96.9 % with Gramella marina KMM 6048T. The DNA-DNA relatedness values were <35 % between strain KT0803T and type strains with >98.2 % 16S rRNA gene sequence identity. Based on the chemotaxonomic, phenotypic and genomic characteristics, strain KT0803T has been assigned to the genus Gramella, as Gramella forsetii sp. nov. The type strain is KT0803T (=DSM 17595T=CGMCC 1.15422T). An emended description of Gramella gaetbulicolaCho et al. 2011 is also proposed.

Comparing polysaccharide decomposition between the type strains Gramella echinicola KMM 6050(T) (DSM 19838(T)) and Gramella portivictoriae UST040801-001(T) (DSM 23547(T)), and emended description of Gramella echinicola Nedashkovskaya et al. 2005 emend. Shahina et al. 2014 and Gramella portivictoriae Lau et al. 2005.

Strains of the genus Gramella (family Flavobacteriacae, phylum Bacteroidetes) were isolated from marine habitats such as tidal flat sediments, coastal surface seawater and sea urchins. Flavobacteriaceae have been shown to be involved in the decomposition of plant and algal polysaccharides. However, the potential to decompose polysaccharides may differ tremendously even between species of the same genus. Gramella echinicola KMM 6050(T) (DSM 19838(T)) and Gramella portivictoriae UST040801-001(T) (DSM 23547(T)) have genomes of similar lengths, similar numbers of protein coding genes and RNA genes. Both genomes encode for a greater number of peptidases compared to 'G. forsetii'. In contrast to the genome of 'G. forsetii', both genomes comprised a smaller set of CAZymes. Seven polysaccharide utilization loci were identified in the genomes of DSM 19838(T) and DSM 23547(T). Both Gramella strains hydrolyzed starch, galactomannan, arabinoxylan and hydroxyethyl-cellulose, but not pectin, chitosan and cellulose (Avicel). Galactan and xylan were hydrolyzed by strain DSM 19838(T), whereas strain DSM 23547(T) hydrolyzed pachyman and carboxy-methyl cellulose. Conclusively, both Gramella type strains exhibit characteristic physiological, morphological and genomic differences that might be linked to their habitat. Furthermore, the identified enzymes mediating polysaccharide decomposition, are of biotechnological interest.