Physiological properties of Pseudomonas sp. strain MT-1, denitrifier from the 11,000 m-depth of Mariana Trench

In the present study, we investigated the physiological properties of Pseudomonas sp. strain MT-1 isolated from the mud of Mariana Trench. Strain MT-1 was closely related with members of the genus Pseudomonas, especially with Pseudomonas chloritidismutans and Pseudomonas stutzeri on the basis of 16S rDNA sequence. The DNA-DNA hybridization values between strain MT-1 and Pseudomonas reference strains were significantly lower than those accepted as the phylogenetic definition of a species. MT-1 had polar flagellum, and was facultative anaerobe. The growth occurred in an NaCl concentration of about 0-10% (optimum: 1-2%), in pH of about 6-10 (optimum: 7-8), and in temperature of about 4-45 °C (optimum: 32-35 °C). The G+C content of the DNA was 60.5% mol%. The major quinone was ubiquinone-9. The major fatty acid in strain MT-1 was C16:0 (hexadecanoic acid), C16:1 (hexadecenoic acid) and C18:1 (octadecenoic acid). The organism showed adaptational properties to deep-sea environment compared with the reference strains.