Phaeobacter cretensis sp. nov. and Phaeobacter bryozoorum sp. nov., isolated from seawater from off the coast of Crete and from Roskilde Fjord in Denmark

Two Gram-negative, motile, rod-shaped bacteria, designated as C3_T13_0^T and A36a-5a^T, were isolated from marine environments collected off the coast of Crete, Greece, and from a biofilm in Jyllinge Harbor in Roskilde Fjord, Denmark, respectively. 16S rRNA gene phylogeny revealed that the two strains belong to the genus <i>Phaeobacter</i>. The major cellular fatty acids (>5%) were C_{18 : 1} <i> ω</i>7<i>c</i> for strain A36a-5a^T and C_{18 : 1} <i> ω</i>7<i>c</i>, C_{18 : 2} <i> ω</i>7,13 and C_{16 : 0} for strain C3_T13_0^T. The major respiratory quinone was ubiquinone-10, and the predominant polar lipids were phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine for both strains. C3_T13_0^T and A36a-5a^T both produce the antimicrobial compound tropodithietic acid. The C3_T13_0^T strain grows at temperatures between 8 and 37 °C with an optimum of 25 °C, whereas A36a-5a^T grows between 5 and 37 °C with an optimum of 30 °C. The salinity range for growth was 2-9 % NaCl (w/v) for C3_T13_0^T with an optimum of 3-4% and 0-10% NaCl (w/v) for A36a-5a^T with an optimum of 2-6%. The genomes of the two strains shared an average nucleotide identity (ANI) of 84% and had lower than 87% ANI when compared with genomes of <i>Phaeobacter</i> spp. type strains. The genome of C3_T13_0^T was 4,432,895 bp with a G+C content of 55.96 mol%, and the genome of A36a-5a^T was 4,050,005 bp with a G+C content of 61.37 mol%. Based on the phylogenetic and phenotypic analyses presented here, the two isolates C3_T13_0^T (=DSM 118664^T=LMG 33738^T) and A36a-5a^T (=DSM 118663^T=LMG 33737^T) are considered to represent two novel species belonging to the genus <i>Phaeobacter</i>, for which the names <i>Phaeobacter cretensis</i> sp. nov. and <i>Phaeobacter bryozoorum</i> sp. nov. are proposed, respectively.