Delftia litopenaei sp. nov., a poly-β-hydroxybutyrate-accumulating bacterium isolated from a freshwater shrimp culture pond

Abstract

A Gram-negative, short-rod-shaped, motile, non-spore-forming and poly-β-hydroxybutyrate-accumulating bacterial strain, designated wsw-7(T), was isolated from a freshwater shrimp culture pond in Taiwan and was characterized using a polyphasic taxonomic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that the closest relatives of strain wsw-7(T) were Delftia lacustris 332(T), Delftia tsuruhatensis T7(T) and Delftia acidovorans ATCC 15668(T), with sequence similarities of 98.5, 98.4 and 97.9%, respectively. Phylogenetic trees obtained with 16S rRNA gene sequences or the polyhydroxyalkanoate synthase (phaC) gene sequences revealed that strain wsw-7(T) and these three closest relatives formed an independent phylogenetic clade within the order Burkholderiales. Strain wsw-7(T) contained summed feature 3 (comprising C(16:1)ω7c and/or C(16:1)ω6c), C(18:0) and C(18:1)ω7c as predominant fatty acids. The major isoprenoid quinone was Q-8 and the DNA G+C content was 67.6 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an uncharacterized aminolipid and several uncharacterized phospholipids. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain wsw-7(T) represents a novel species in the genus Delftia, for which the name Delftia litopenaei sp. nov. is proposed; the type strain is wsw-7(T) ( = BCRC 80212(T) = LMG 25724(T)).