A novel cold-adapted pyrethroid-degrading esterase from Bacillus subtilis J6 and its application for pyrethroid-residual alleviation in food matrix

Prolonged and widespread use of pyrethroid pesticides a significant concern for human health. The initial step in pyrethroid bioremediation involves the hydrolysis of ester-bond. In the present study, the esterase genes est10 and est13, derived from Bacillus subtilis, were successfully cloned and expressed in Escherichia coli. Recombinant Est10 and Est13 were classified within esterase families VII and XIII, respectively, both of which exhibited conserved G-X-G-X-G motifs. These enzymes demonstrated the capability to degrade pyrethroids, with Est13 exhibiting superior efficiency, and thus was selected for further investigation. Est13 exhibited the highest β-cypermethrin-hydrolytic activity at 25°C and a pH of 7.0, showing robust stability in low and medium temperature environment and a broad range of pH levels. Furthermore, Est13 displayed notable resistance to organic solvents and NaCl, coupled with wide substrate specificity. Notably, the degradation products of β-cypermethrin by Est13 were identified as 3-phenoxybenzoic acid, 3-phenoxybenzaldehyde, and 3-(2,2-Dichloroethenyl)-2,2-dimethyl-cyclopropanecarboxylate, with key catalytic triads comprising Ser93, Asp192, and His222. Moreover, Est13 exhibited substantial efficiency in removing β-cypermethrin residues from various food items such as milk, meat, vegetables, and fruits. These findings underscore the potential of Est13 for application in the bioremediation of pyrethroid-contaminated environments and reduction of pyrethroid residues in food products. Pyrethroids are a class of widely used insecticide and induce risks to environment and human health. The hydrolysis of ester-bond is the key and efficient step in bioremediation towards pyrethroid by enzyme and microorganisms. In this work, two pyrethroid-degrading esterase genes were obtained from Bacillus subtilis J6 isolated from broiler intestinal tract. Est13 is a cold-adapted enzyme, and also can tolerance against wide pH, organic solvents and NaCl. It can achieve high efficiency with low energy consumption, showing the potential to bioremediate the most of pyrethroid-contaminated environment. Also, Est13 can remove pyrethroid residual from agricultural products and alleviate exposure risk.