Biodegradation of hazardous naphthalene and cleaner production of rhamnolipids — Green approaches of pollution mitigation

Toxic and hazardous waste poses a serious threat to human health and the environment. Green remediation technologies are required to manage such waste materials, which is a demanding and difficult task. Here, effort was made to explore the role of Pseudomonas aeruginosa SR17 in alleviating naphthalene via catabolism and simultaneously producing biosurfactant. The results showed up to 89.2% naphthalene degradation at 35 °C and pH 7. The GC/MS analysis revealed the generation of naphthalene degradation intermediates. Biosurfactant production led to the reduction of surface tension of the culture medium to 34.5 mN/m. The biosurfactant was further characterized as rhamnolipids. LC-MS of the column purified biosurfactant revealed the presence of both mono and di rhamnolipid congeners. Rhamnolipid find tremendous application in medical field and as well as in detergent industry and since they are of biological origin, they can be used as favorable alternative against their chemical counterparts. The study demonstrated that catabolism of naphthalene and concurrent formation of rhamnolipid can result in a dual activity process, namely environmental cleanup and production of a valuable microbial metabolite. Additionally, the present-day application of rhamnolipids is highlighted.