Bioremediation of polycyclic aromatic hydrocarbons contaminated soils/water for environmental remediation

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants widely found in the environment due to natural and anthropogenic sources, including fossil fuel combustion, industrial emissions, and vehicle exhaust. These hydrophobic compounds are resistant to degradation, bioaccumulate in ecosystems/water, and pose significant environmental and health risks, including carcinogenesis and respiratory disorders. Conventional remediation methods, such as chemical and physical treatments, are often costly, energy-intensive, and environmentally disruptive, prompting the search for sustainable alternatives. Microbial bioremediation has emerged as an effective solution, leveraging the natural ability of microorganisms to degrade PAHs through enzymatic pathways. This approach offers an eco-friendly, cost-effective method for PAHs removal from contaminated sites. This review focuses on the biodegradation of various PAHs, such as naphthalene, phenanthrene, anthracene, and pyrene, by bacteria including Pseudomonas, Mycobacterium, Rhodococcus, and marine species from the Novosphingobium genus. These microbes use dioxygenase enzymes to initiate the breakdown of PAHs into less toxic intermediates. Additionally, the review explores the role of biosurfactants and biofilms in enhancing the bioavailability of PAHs, promoting more efficient degradation. This paper also discusses the advantages of microbial consortia, where multiple species collaborate to degrade a broader range of PAHs. Recent advancements in genetic engineering, synthetic biology, and nanotechnology are highlighted as promising tools to further enhance microbial degradation efficiency. The microbial bioremediation represents a sustainable solution to PAHs contamination, complementing traditional methods and offering significant potential for environmental restoration and human health improvement.