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

Imidacloprid is an insecticide of systemic nature thatexhibitsan adverse impact on several non-target organisms. In the presentstudy, potential bacteria have been isolated and used for biodegradationof imidacloprid in batch studies and stirred tank reactor. The optimumprocess condition for degradation has been found to be at pH 7, atemperature of 35 & DEG;C, and a shaking speed of 150 rpm. Maximumdegradation of 78% has been achieved by the bacterial consortium inthe batch study, while, in the reactor, it increases to 90%. Kineticsanalysis suggests that the Teisser model best fits the experimentaldata, with a correlation coefficient (R (2)) of 0.98. Ecotoxicological assessment using luminescent bacteriareveals 40% and 90% inhibition in luminescence in the case of untreatedsample upon exposure for 30 min and 24 h, respectively, while thevalues obtained in the case of treated samples are 9% and 29%, respectively.Cytotoxicity assessment indicates 60% reduction in cell proliferationin untreated samples and <10% cell proliferation inhibition intreated samples, indicating a considerable decrease in toxicity post-bacterialtreatment.

Automated summary

This study isolated potential bacteria for the biodegradation of imidacloprid and found that the optimal degradation conditions are pH 7, temperature of 35°C, and shaking speed of 150 rpm. The bacterial consortium achieved 78% degradation in batch studies and 90% degradation in the reactor. Kinetics analysis showed that the Teisser model best fit the experimental data, with a correlation coefficient (R2) of 0.98. Ecotoxicological assessment revealed decreased luminescence inhibition and cytotoxicity after bacterial treatment.