Expression of a novel hydrolase MhpC in Brevibacillus parabrevis BCP-09 and its characteristics for degrading synthetic pyrethroids.

ABSTRACT

Synthetic pyrethroids are widely used insecticides which may cause chronic diseases in non-target organisms upon long-term exposure. Microbial degradation offers a reliable method to remove them from the environment. This study focused on Brevibacillus parabrevis BCP-09 and its enzymes for degrading pyrethroids. The predicted deltamethrin-degrading genes phnA and mhpC were used to construct recombinant plasmids. These plasmids, introduced into Escherichia coli BL21(DE3) cells and induced with L-arabinose. The results indicated that the intracellular crude enzyme efficiently degraded deltamethrin by 98.8 %, ß-cypermethrin by 94.84 %, and cyfluthrin by 73.52 % within 24 h. The hydrolytic enzyme MhpC possesses a catalytic triad Ser/His/Asp and a typical "Gly-X-Ser-X-Gly" conservative sequence of the esterase family. Co-cultivation of induced E. coli PhnA and E. coli MhpC resulted in degradation rates of 41.44 ± 3.55 % and 60.30 ± 4.55 %, respectively, for deltamethrin after 7 d. This study states that the degrading enzymes from B. parabrevis BCP-09 are an effective method for the degradation of pyrethroids, providing available enzyme resources for food safety and environmental protection.