Isolation,Identification and Characteristics of a Cypermethrin-degrading Bacterium GF31

A bacterium strain named GF31,which could use cypermethrin as the sole source of carbon,was isolated from a polluted soil. Through morphological observation,16S rDNA genetical analysis,physiological and biochemical tests,the strain GF31 was identified as Pseudomonas aeruginosa. The optimal pH and inoculating quantity for the cypermethrin degradation were 7.0 and 10%,respectively. The degradation activity of strain GF31 could keep at a high level even when the cypermethrin concentration was increased to 300 mg/L. Furthermore,nitrogen sources were proved to be able to accelerate the degradation rate,especially the organic nitrogen sources. When 0.5 g/L peptone was added,the average degrading rate of 100 mg/L was 13.64 mg/(L·d) ,which was two times as that of the ammonium sulfate. It was preliminarily speculated thatthe degraded products and the alkaline environment might inhibit the growth and activity of strain GF31.