Biodegradation of Phenanthrene by Pseudomonas sp. JPN2 and Structure-Based Degrading Mechanism Study

The strain Pseudomonas sp. JPN2 had a high potential to degrade phenanthrene degrading 98.52 % of the initial amount of 100 mg L^-1 after 10 days incubation. The analysis of metabolites demonstrated that the cleavage of phenanthrene started at the C₉ and C₁₀ positions on the aromatic ring by the dioxygenation reaction, and then further degraded via a phthalate pathway. To understand the interaction between phenanthrene and the amino acid residues in the active site of the target enzyme, a molecular docking simulation was performed. The results showed that the distances of C₉-O₁ and C₁₀-O₂ atoms were 3.47 and 3.67 Å, respectively. The C₉ and C₁₀ positions of the phenanthrene ring are much closer to the dioxygen molecule in the active site relative to the other atoms. Therefore, the C₉ and C₁₀ positions are vulnerable to attack in the initial oxygenation process.