Comprehensive genomic analysis of a novel

Environmental pollution treatment is a worldwide challenge. Biological treatments are preferred to remedy the pollutants owing to higher efficiency and biocompatibility. Here, 18 indigenous bacterial strains with the usability of toluene as the sole carbon and energy source were screened, resulting in the selection of one isolate that was most capable of removing toluene. This isolate was characterized as a rod-shaped, gram-positive, spore-forming, halotolerant, catalase-positive, motile bacterium. The optimal temperature (40°C), pH (8), and NaCl concentration (50 g/L) for toluene removal were determined. Then, the experiment with four variables (petrochemical effluent dilution, carbon source, minerals, and amount of municipal wastewater) was designed using a Taguchi L16 orthogonal array. Ultimately, a 38.15% chemical oxygen demand decrease, as the best removal efficiency, was achieved. Gas chromatography-mass spectrometry analysis of bacterial metabolites assisted in recognizing the toluene degradation products, such as acetate and 2-propanone, indicating a meta-pathway of toluene decomposition. Next-generation sequencing strategy followed by core/pan-genome analysis indicated that the genome of the strain encompasses an assembly size of 5,154,622 bp with a content of 35.34% comprising 3,437 core and 2,258 accessory genes. Phylogenetic and multi-locus sequence typing studies confirmed that the strain belongs to the genus IMPORTANCE: The purpose of the present study was to develop a feasible process for the treatment of heavily contaminated Mahshahr petrochemical effluent. Since regular treatment of this effluent was inefficient, isolation of an indigenous bacterium with the ability to decompose toluene (the main pollutant of the effluent) and use it as a biological material to treat wastewater containing aromatic compounds on an industrial scale was very important.