Bioremediation of Imidacloprid in a Stirred Tank Reactor Using Bacterial Consortium: Kinetic Analysis and Toxicity Assessment

Abstract

Imidacloprid is an insecticide of systemic nature that exhibits an adverse impact on several non-target organisms. In the present study, potential bacteria have been isolated and used for biodegradation of imidacloprid in batch studies and stirred tank reactor. The optimum process condition for degradation has been found to be at pH 7, a temperature of 35 °C, and a shaking speed of 150 rpm. Maximum degradation of 78% has been achieved by the bacterial consortium in the batch study, while, in the reactor, it increases to 90%. Kinetics analysis suggests that the Teisser model best fits the experimental data, with a correlation coefficient (R2) of 0.98. Ecotoxicological assessment using luminescent bacteria reveals 40% and 90% inhibition in luminescence in the case of untreated sample upon exposure for 30 min and 24 h, respectively, while the values obtained in the case of treated samples are 9% and 29%, respectively. Cytotoxicity assessment indicates 60% reduction in cell proliferation in untreated samples and <10% cell proliferation inhibition in treated samples, indicating a considerable decrease in toxicity post-bacterial treatment. © 2023 American Chemical Society