Environmental Impacts, Health Risks, and Biodegradation Strategies of Fluorene and Other Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds, composed of two or more fused benzene rings sourced from unburned fossil fuels and petroleum, recognized for their wide presence in the environment and harmful impacts on human health and ecosystems. PAHs pose remarkable challenges to living habitats due to their mutagenic properties. Fluorene is a low-molecular-weight heterocyclic aromatic hydrocarbon with multiple industrial applications, for example, pigments, fluorescents, and pharmaceuticals. Its xenobiotic activities on living cells may lead to severe health concerns including cancer and organ damage. The degradation of PAHs through several physicochemical reactions is costly, labor-intensive, time-consuming, and detrimental to the environment. However, biodegradation of PAHs using microorganisms such as bacteria, fungi, and algae leads to a sustainable and cost-effective method. Despite ongoing research, finding potent microbial strains capable of degrading PAHs comprehensively is a significant challenge. This review highlights the toxicity of PAHs (especially fluorene) on the environment and summarizes effective microorganisms and their approaches for meaningful PAH bioremediation.