The Power of Halophilic Microorganisms in Hydrocarbon Degradation for Environmental Sustainability

Hydrocarbon contamination is a pressing environmental concern resulting from the extensive use of fossil fuels, industrial discharge, and accidental oil spills. Bioremediation in saline and hypersaline environments is particularly challenging, as conventional microorganisms often show limited survival. Halophilic microorganisms, adapted to salinity ranges of 3–30% NaCl, have emerged as promising candidates for hydrocarbon degradation under such extreme conditions. These microorganisms efficiently degrade alkanes and polycyclic aromatic hydrocarbons (PAHs) through enzymatic oxidative pathways involving alkane monooxygenases, dioxygenases, and dehydrogenases. Reported degradation efficiencies range from 60% to 95% under optimised laboratory conditions. Genera such as Halomonas, Marinobacter, Oceanobacillus, and Pseudomonas contribute significantly to crude oil and PAH degradation in saline environments. Despite their potential, challenges such as slow degradation kinetics, nutrient limitations, accumulation of toxic intermediates, and scalability constraints restrict large-scale applications. Future research should focus on omics-based pathway elucidation, metabolic engineering, biosurfactant enhancement, and pilot-scale validation to improve efficiency and environmental sustainability. This review highlights the metabolic mechanisms, environmental relevance, and practical prospects of halophilic microorganisms in hydrocarbon bioremediation.