Pseudomonas extremaustralis sp. nov., a Poly(3-hydroxybutyrate) Producer Isolated from an Antarctic Environment

A Gram-negative, mobile, rod-shaped, non-spore-forming bacterium (strain 14-3^T) was isolated from a temporary pond in Antarctica. On the basis of 16S rRNA gene sequence similarity, strain 14-3^T was shown to belong to the genus Pseudomonas sensu stricto. Physiological and biochemical tests supported the phylogenetic affiliation. Strain 14-3^T is closely related to Pseudomonas veronii DSM 11331^T, sharing 99.7% sequence similarity. DNA–DNA hybridization experiments between the two strains showed only moderate reassociation similarity (35.1%). Tests for arginine dihydrolase and nitrate reduction were positive, while those for denitrification, indol production, glucose acidification, urease, ß-galactosidase, esculin, caseine and gelatin hydrolysis were negative. Growth of this bacterium occurred in a range from 4 to 37°C but not at 42°C. It accumulated poly(3-hydroxybutyrate) when grown on sodium octanoate medium. Strain 14-3^T therefore represents the type strain of a new species, for which the name Pseudomonas extremaustralis sp. nov. is proposed. The type strain 14-3^T has been deposited as DSM 17835^T and as CIP 109839^T.