Abstract

The increased use of organophosphorus pesticides and their persistence in soil pose a great menace to human health, animals, and milieu. Bioremediation can be applied for the degradation of such persistent chemicals. The aim of our study is based on the degradation of the organophosphorus pesticide, Quinalphos in the brand name “Ekalux” by using microorganisms that are already a part of the natural soil microflora. Enterobacter cloacae which have the capacity to degrade quinalphos were isolated from contaminated soil. The pre-isolated strain of E. cloacae (NCBI Accession No: CP035738.1) is used as a biodegradative agent of Quinalphos. The percentage of degradation of quinalphos was identified through a chemical reaction with a DPAAP reagent (diazotized para aminoacetophenone). Several factors can limit the rate of biodegradation such as temperature, pH, glucose concentration, NaCl concentration, and so on. A piece of these factors must be optimized for the secluded organism to achieve optimal degradation of Quinalphos. For biodegradation studies, the isolated organism E. clocae were inoculated into minimal media with Quinalphos. The efficiency of both free cell cultures and immobilized cell cultures was checked along with optimization studies. Immobilized cells were found to give better results than free cell cultures by 9%–15%. 35°C ± 2°C temperature, 6.5– 7.5 pH, and approximately 1% glucose concentration were found to be optimum for the most efficient biodegradation of quinalphos by E. cloacae.

Key words: 16s rRNAsequencing, Enterobacter cloacae, Quinalphos, Immobilized cell, Biodegradation