Vreelandella aydingkolensis sp. nov., a polyhydroxybutyrate-producing halophilic bacterium isolated from Aydingkol Lake, China.

A Gram-negative, aerobic, halophilic bacterium, designated as strain TD01T, was isolated from an environmental sample collected from Aydingkol Lake, a saline lake in Xinjiang, China. Cells were rod-shaped and formed light yellow, circular, smooth and glossy colonies on Luria-Bertani agar supplemented with 60 g l-1 NaCl. Strain TD01T grew at 20-41 °C (optimum 30 °C), pH 5.0-10.0 (optimum 7.0-8.0) and in the presence of 2-20% (w/v) NaCl [optimum 8-11% (w/v)]. The strain was catalase- and oxidase-positive, reduced nitrate and did not grow anaerobically in the absence or presence of nitrate, nitrite or fumarate as an exogenous electron acceptor. The strain was capable of accumulating intracellular polyhydroxybutyrate. The predominant respiratory quinone was ubiquinone-9. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain TD01T belonged to the genus Vreelandella and was most closely related to Vreelandella zhaodongensis (99.65%), Vreelandella alkaliphila (98.94%) and Vreelandella venusta (98.73%). Analysis of the previously published complete genome sequence showed a genome size of 4.13 Mb with a DNA G+C content of 52.71 mol%. Average nucleotide identity and digital DNA-DNA hybridization values between strain TD01T and its closest relatives were below the accepted thresholds for species delineation. Based on the results of polyphasic taxonomic analyses, we propose that strain TD01T be classified as the type strain of a novel species named Vreelandella aydingkolensis sp. nov. Strain TD01T has been deposited in the China General Microbiological Culture Collection Center (CGMCC), Beijing, China, under the collection number CGMCC 4353T, in the Spanish Type Culture Collection (CECT), Valencia, Spain, under the collection number CECT 31432T, and in the American Type Culture Collection (ATCC), Manassas, VA, USA, under the collection number ATCC TSD-628ᵀ.