Isolation and molecular biological characterization of biphenyl degrading Rhodococcus sp. Strain VR43-1

The genetic structures (bphA1 genes) encoding biphenyl 2,3-dioxygenase (BDO) - a key enzyme in the aerobic catabolism of biphenyl and polychlorinated biphenyls (PCBs, persistent and toxic pollutants), are revealed in the microbial community of bottom sediments of the river Chapayevka, which flows through the territory of the chemical plant «Mid-Volga Chemical enterprise» (Chapaevsk, Samara region). The similarity (95,8-99,7%) of the studied nucleotide sequences with the genes of the BDO α-subunit and another dioxygenases (benzene / toluene subfamily DO) of genus Rhodococcus strains was found. An active strain-destructor of biphenyl, designated VR43-1, was isolated from the bottom sediments sample by enrichment cultivation. А comparison of the nucleotide sequences of 16S rRNA genes with homologous sequences from the EzBioCloud database, showed that strain VR43-1 had the highest level of similarity (100%) with the type strain R. wratislaviensis NBRC 100605T. A comparison of the bphA1 gene of the VR43-1 strain with the bphA1 genes of the active biphenyl/PCB destructor R. jostii RHA1 and the R. wratislaviensis strains P13 and Ch628 showed a similarity of 99.1% and 100%, respectively.