Degradation of Pyrethroid Insecticide- cypermethrin (25% EC) using Soil Microorganisms and Detection of Degradation Products

Abstract

Background: Cypermethrin is used extensively to kill the pests that decreases the crop yield. Excessive use of cypermethrin results in soil and water contamination, thus affecting soil microflora and the aquatic life. Thus, removal of cypermethrin is particularly important. Different physical and chemical methods are available for the cypermethrin removal but are time consuming and costly. So, microbial degradation of cypermethrin is important. The present study aimed to isolate and identify cypermethrin degrading organisms, detection of the cypermethrin degradation product by GC- MS analysis and detection of residual amount of cypermethrin from the medium.Methods: In this laboratory investigation, soil samples were collected from different farms and isolation and identification of microorganisms capable of cypermethrin degradation was performed. Further, detection of residual cypermethrin concentration, cod value and cypermethrin degradation products using GC- MS analysis was performed.Result: Cypermethrin degrading microorganisms were isolated and identified as P. aeruginosa and K. pneumoniae. These microorganisms degraded 200mg\lit cypermethrin and the cypermethrin degradation products were detected and identified by comparing with the standard database. Residual amount of cypermethrin was detected from the medium by colorimetric method. Residual cypermethrin concentration was decreased with time in the test indicating cypermethrin degradation ability of the P. aeruginosa and K. pneumoniae. Further, COD value was determined and COD value was found to be decreased in the medium in presence of P. aeruginosa and K. pneumoniae indicating cypermethrin removal.