Biodegradation of naphthalene - Ecofriendly approach for soil pollution mitigation

Naphthalene (NPT), a widely used household pest repellent and insecticide obtained from crude oil, serves as a toxic pollutant to non-target living matter. The stable and resistant nature of NPT makes it difficult to degrade through the physiochemical processes. The present study investigated the bacterial degradation of NPT isolated from crude oil-contaminated soil. Initially, the potent bacteria, Bacillus sp. GN 3.4, were isolated by enrichment culture method and subsequently assessed for NPT biodegradation. The optimum conditions for NPT biodegradation were pH 7.0 at 37 °C, 80 mg/L (initial NPT), 3% v/v (inoculum dose), and 7 days of treatment which showed 100% biodegradation. Furthermore, GC-MS analysis revealed the presence of degradation metabolites, namely, salicylate and hydroquinone indicating potential metabolic pathways. Considering the water-solubility and non-toxic nature of these metabolites, the results imply that Bacillus sp. GN 3.4. could potentially play a role in bioremediation by aiding in eliminating NPT from the soil.