This RIRDC project forms part of the overall CSIRO/Orica bioremediation program. It aims to isolate and characterise one or more gene/enzyme systems that can detoxify pyrethroid insecticides. It complements work elsewhere in the program that is developing enzymes for detoxifying organophosphate, carbamate and endosulfan insecticides and thiocarbamate herbicides. Some of the other enzymes have already been developed to the point of laboratory-scale proof-of-concept.
This report describes the development of biochemical techniques for assaying the enzymatic hydrolysis of pyrethroid insecticides, and the kinetic analysis of a suite of esterase enzymes for several pyrethroid substrates. The analysis identifies two enzymes that between them have significant hydrolytic activity against almost all the pyrethroids and their isomers tested. These enzymes will now be transferred to Orica for further evaluation and implementation research. Some further evaluation of additional enzymes will also be needed to obtain activities against the remaining problematic isomers.