A novel polyhydroxyalkanoate-storing bacterium Thauera carbonocopians sp. nov. isolated from a sequencing batch...

A Gram-negative bacterial strain, namely Sel9^T, was isolated from a sequencing batch reactor for the selection of a polyhydroxyalkanoate (PHA)-storing microbial biomass, fed with volatile fatty acids. 16S rRNA gene sequence and core genome analyses performed with maximum likelihood method evidenced that Sel9^T belongs to the genus Thauera with the highest phylogenetic relatedness with Thauera butanivorans DSM 2080^T (98.99%) and Thauera linaloolentis DSM 12138^T (98.49%). Digital DNA-DNA hybridization and Average Nucleotide Identity (OrthoANI) values between strain Sel9^T and the closest taxon, T. butanivorans DSM 2080^T, were 53.20 and 93.71%, respectively, which were below the cut-off values for species delineation. The predominant cell fatty acids were summed feature 3 (C16:1 ω6c/C16:1 ω7c), C16:0 and summed feature 8 (C18:1 ω6c/C18:1 ω7c). Phosphatidylethanolamine and phosphatidylglycerol were the main polar lipids in the cell. Genome mining detected nine biosynthetic gene clusters, including ectoine, pyrroloquinoline quinone (PQQ)-redox and a genus-rare nonribosomal peptide synthetase (NRPS) gene cluster, plus the acyclic terpene utilization pathway predicting growth on linalool. The combination of phylogenetic, chemotaxonomic and phenotypic features led to consider strain Sel9^T as a representative of a novel species within the genus Thauera. Therefore, given its remarkable ability to store carbon sources, for the type strain Sel9^T (=LMG 33225^T =BAC RE RB 2381^T =VUCC 376^T) the name of Thauera carbonocopians sp. nov. is here proposed. Eventually, this study represents the first comprehensive investigation of biosynthetic gene clusters and the comparative genomics analysis of PHA metabolism within the genus Thauera.