<i>Microbulbifer gwangyangensis</i> sp. nov. and <i>Microbulbifer pacificus</i> sp. nov., isolated from marine environments

다국어 초록 (Multilingual Abstract)

<P>Two novel Gram-stain-negative, chemoheterotrophic and strictly aerobic bacteria, strains GY2<SUP>T</SUP> and SPO729<SUP>T</SUP>, were isolated from a tidal flat at Gwangyang Bay in Korea and a marine sponge sample from the Pacific Ocean, respectively. The two strains were halotolerant, catalase- and oxidase-positive, and non-motile rods. Optimum temperature and pH for growth of both strains were observed to be 35 °C and pH 7.0–7.5, but optimum salinity for strain SPO729<SUP>T</SUP> [2–3 % (w/v)] was slightly higher than that for strain GY2<SUP>T</SUP> (1–2 %). The major cellular fatty acids of both strains were C<SUB>16 : 0</SUB>, iso-C<SUB>15 : 0</SUB>, iso-C<SUB>17 : 0</SUB>, iso-C<SUB>17 : 1</SUB>ω9<I>c</I>, C<SUB>18 : 1</SUB>ω7<I>c</I>, iso-C<SUB>11 : 0</SUB> and iso-C<SUB>11 : 0</SUB> 3-OH. The genomic DNA G+C contents of strains GY2<SUP>T</SUP> and SPO729<SUP>T</SUP> were 55.1 and 57.9 mol%, respectively, and ubiquinone 8 (Q-8) was detected as the sole respiratory quinone from the two strains. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains GY2<SUP>T</SUP> and SPO729<SUP>T</SUP> formed tight phyletic lineages with members of the genus <I>Microbulbifer</I>. Strain GY2<SUP>T</SUP> was closely related to <I>Microbulbifer okinawensis</I> ABABA23<SUP>T</SUP> (98.2 %), strain SPO729<SUP>T</SUP> (98.0 %) and <I>Microbulbifer donghaiensis</I> CN85<SUP>T</SUP> (97.0 %); strain SPO729<SUP>T</SUP> was closely related to <I>M. okinawensis</I> ABABA23<SUP>T</SUP> (98.3 %) and <I>M. donghaiensis</I> CN85<SUP>T</SUP> (98.2 %). The DNA–DNA relatedness values of strain GY2<SUP>T</SUP> with <I>M. okinawensis</I> ABABA23<SUP>T</SUP>, strain SPO729<SUP>T</SUP> and <I>M. donghaiensis</I> CN85<SUP>T</SUP> were 40.0±2.1 %, 13.1±3.9 % and 16.2±5.8 %, respectively, whereas those of strain SPO729<SUP>T</SUP> with <I>M. okinawensis</I> ABABA23<SUP>T</SUP> and <I>M. donghaiensis</I> CN85<SUP>T</SUP> were 48.0±4.0 % and 34.6±9.3 %, respectively. On the basis of phenotypic and molecular features, it is concluded that the two strains GY2<SUP>T</SUP> and SPO729<SUP>T</SUP> represent two novel species of the genus <I>Microbulbifer</I>, for which the names <I>Microbulbifer gwangyangensis</I> sp. nov. and <I>Microbulbifer pacificus</I> are proposed; the type strains are GY2<SUP>T</SUP> ( = KACC 16189<SUP>T</SUP> = JCM 17800<SUP>T</SUP>) and SPO729<SUP>T</SUP> ( = KCCM 42667<SUP>T</SUP> = JCM 14507<SUP>T</SUP>), respectively.</P>