Comparative evaluation of pyrene degrading potential of three gram-negative bacterial strains: Acinetobacter baumannii BJ5, Acinetobacter pitti NFL, and Enterobacter cloacae BT

In recent years, the presence of Polycyclic Aromatic Hydrocarbons (PAHs), such as pyrene, exhibiting toxic behaviour towards microbes, flora, fauna, and humans, has escalated significantly. Notably, this research has exploited the remarkable capabilities of Acinetobacter baumannii BJ5, Acinetobacter pitti NFL, and Enterobacter cloacae BT to investigate the dynamics of pyrene mineralization, at substantially high-concentration over a range of 600–1000 mg/L concentration. Investigating biochemical pathways in biodegradation is crucial for understanding the intricate mechanisms underlying the growth, degradation, and environmental adaptation of the microorganisms. In the present study, metabolites generated during pyrene mineralization in E. cloacae BT were identified implicating phthalic acid pathway mediated biodegradation. The decomposition of pyrene by E. cloacae BT succeeded via initial ring oxidation and subsequent dehydrogenation to yield phthalic acid and pyrocatechol as the key intermediates. This research enhances our knowledge of pyrene degradation mechanisms in gram-negative bacteria, paving the way for proactive strategies to improve its removal from the contaminated environments.