Degradation of Polyaromatic Hydrocarbons by Biosurfactant-Producing Pseudomonas aeruginosa NG4

Polyaromatic hydrocarbons (PAHs) are a group of organic pollutants commonly found in the environment due to industrial activities, incomplete burning of fossil fuels, and oil spills. Bioremediation of PAHs has emerged as a promising approach. This study investigated the biodegradation of PAHs (anthracene, naphthalene, phenanthrene, anthraquinone, and anthrone) at 100 ppm to 1000 ppm in the presence of glucose and glycerol by a biosurfactant-producing strain of Pseudomonas aeruginosa NG4. The quality of the biosurfactant produced by the bacterial strain was analyzed via emulsion index (E24), drop-collapse assay, and oil displacement assay. The PAH degradation efficiency was studied by HPLC and degradation metabolites were analyzed using GC-MS. Among all five PAHs (fed at 300 ppm), the highest degradation rates of 91.16 ± 3.64% naphthalene and 41.16 ± 1.64% anthrone were observed by P. aeruginosa NG4 after 10 days of incubation. The assessment of degradation intermediate metabolites revealed the PAH catabolism via the dioxygenase route, which plays a key role in the breakdown of these aromatic compounds. Biodegradation of anthrone by P. aeruginosa NG4 at a 300 ppm level in the media was reported for the first time. This study highlights the potential of P. aeruginosa NG4 as a candidate for the development of bioremediation strategies to mitigate environmental pollution caused by persistent organic pollutants like PAHs.