The Degradation Effects of a Pseudomonas Hydrolase OPHC2 to Organophosphorus Insecticides

Abstract

The degradation effects of OPHC2 to 9 organophosphates and other pesticides were studied. The degrading reaction was carried out for 10 minutes under 37 °C in 50 mmol pH 8.0 Tris-HCl buffer. Organophosphates and sulfonylurea herbicides were detected by HPLC-UV and/or HPLC/MS. It's shown that degradation rates of 70%–100% were achieved for most of the organophosphates after 24 h (chlorpyrifos 100%, phoxim 100%, fenitrothion 99.87%, isocarbophos 100%, dimethoate 78.55%, methamidophos 71.55%, methidathion 87.93%). Pyrethroids were detected by GC-ECD after extracted by hexane. The degrading amounts of 5 pyrethroids were all above 50% after 3 hours (bifenthrin 78.7%, lambda-cyhalothrin 84.6%, permethrin 69.1%, beta-cypermethrin 51.5%, fenvalerate 72.2%). What is interesting, the degrading amount of malathion in its single standard solution was 94.31% while it did not degrade at all in the mixture standard even under superfluous enzyme solution. OPHC2 showed no effect to the sulfonylurea herbicides.

Keywords:

• Enzymatic degradation
• OPHC2
• organophosphates
• Pseudomonas hydrolase
• pyrethroids
• sulfonylurea herbicides

Acknowledgments

This research was supported by China National Basic Research and Development Program-2002CB410805.