2.2-Diphenic Acid: A Reliable Biomarker Of Phenanthrene Biodegradation

Phenanthrene is among the 16 priority pollutant and its mitigation in the environment has been a global concern. It serves as a model compound when it comes to biodgradation study of polyaromatic hydrocarbons (PAHs) because it has both the Bay- and K-region found in most PAH pollutants. Like other PAH pollutants, different means are available for its remediation in the environment, including microbial biodegradation. Diverse species of bacteria and fungi metabolize phenanthrenes as their sole source of carbon and energy. However, bacteria are more diverse in comparison to fungi. This has been shown in published pathways of phenanthrene biodegradation implicating various intermediary metabolites, including 2,2-diphenic acid, which is a downline metabolite of 9,10-dihydroxyphenanthrene. Though the 2,2-diphenic acid has been widely demonstrated to produce carbon (iv) oxide and linked to phthalate, only few has traced salicylic acid as its downstream molecule. 2,2-diphenic acid mounts equivalent position to 1-hydroxy-2-naphthoic acid, metabolite that ends the phenanthrene metabolic pathway. This is because they both produce phthalic acid and salicylic acid. As a product of bacteria and fungi during phenanthrene degradation, 2,2-diphenic acid can serve as a dependable biomarker of phenanthrene metabolism in a polluted habitat, where microbial community exist freely.