Taxonomic and evolutionary insights from comparative genomics of hydrocarbon degrading bacteria isolated from petroleum reservoirs

Petroleum hydrocarbons and their derivatives are compounds widely used in several industries worldwide. Inappropriate disposal or handling of hydrocarbon-derived products may generate environmental and/or health negative impacts. Understanding the genomic traits underlying hydrocarbon degradation by microorganisms may provide valuable information to improve the use of bioremediation-based strategies for the recovery of impacted areas. In this sense, this study aimed to characterize and compare hydrocarbon-degradation genes and pathways of four bacteria isolated from deep oil reservoirs: Micrococcus sp. CBMAI 636, Dietzia maris CBMAI 705, Bacillus subtilis CBMAI 707, Achromobacter xylosoxidans CBMAI 709, via complete genome sequencing and functional annotation. In addition, phylogenetic analyses were carried out seeking to unravel the evolutionary relatedness of such functional genes to those found in different taxa and environments. Genomic analyses confirmed a high genetic potential for hydrocarbon degradation in the studied strains. Comparative genomics indicated the presence of hydrocarbon degradation genes across all strains, suggesting adaptive evolutionary convergence to hydrocarbon-affected environments. Interestingly, Achromobacter xylosoxidans CBMAI 709 exhibited unique orthologous genes that play a crucial role in the capture, uptake and/or breakdown of petroleum compounds, enhancing its adaptability to hydrocarbon-contaminated environments. These are innovative results that provide novel evolutionary insights into the diversity of hydrocarbon-degrading genes and pathways, enriching our understanding of microbial adaptation to hydrocarbon-rich habitats. The findings gathered in this study underscore the potential of these organisms for bioremediation endeavors, paving the way for future applications in environmental polluting restoration.