Tetracycline bioremediation using the novel Serratia marcescens strain WW1 isolated from a wastewater treatment plant

Tetracycline pollution is an emerging threat in aquatic and terrestrial environments because of its widespread applications in human disease, livestock, and aquaculture. Present study, investigated the tetracycline degrading novel Serratia marcescens strain WW1, which was isolated from a wastewater treatment plant (WWTP). Toxicity analysis of tetracycline with strain WW1 indicates that its intermediate metabolites are not toxic for the indicator bacteria and algae. The degradation conditions for the tetracycline optimized using response surface methodology (RSM) were determined as: pH 6.0; temperature, 36 °C; tetracycline concentration, 20 mg L-1; and inoculum size, 100 μL (OD∼0.5). The strain WW1 was able to utilize tetracycline during the growth phase, and it degraded 89.5% of the tetracycline within 48 h. The degradation kinetics suggested the strain perform significant tetracycline removal with half-life (t1/2) 239.04 and 12.44 h in control and treatments. Tetracycline and its intermediates were analyzed using High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectroscopy (LC-MS). It was observed that strain WW1 could efficiently metabolize the tetracycline within 48 h of experiment. The ability of strain WW1 to degrade tetracycline justifies its use as an environmentally-useful bacterium. Therefore, the present study demonstrated that the degradation of antibiotics is possible using indigenous microbial strains.