Isolation, Identification and Degradation of Carbofuran-degrading Strain CFDS-1*

Abstract

Carbofuran(2,3-dihydro-2,2-dimethyl-7-benzofuranoyl N-methylcarbamate) was first introduced into China in 1979 as a pesticide and is extensively used as a soil-incorporated N-methylcarbamate insecticide to control a variety of insect pests that infest many kinds of crops,such as corn and potato.Carbofuran is of a concern due to its relatively high mammalian toxicity and relatively high mobility in soil.Some N-methylcarbamate compounds and their metabolites can be sufficiently mobile in certain soil,thus considered as potential pollutants of ground and surface waters.One carbofuran-degrading strain named CFDS-1 was isolated from soil polluted by carbofuran for a long time.According to its physiological biochemical characters,and the homology analysis of its 16S rDNA sequence(GenBank accession No.AY702969),CFDS-1 was primarily identif ied as Sphingomonas sp.CFDS-1 was able to completely degrade carbofuran in medium within 48 hours at the initial concentration of 100 mg L-1.CFDS-1 could well degrade carbofuran at concentrations from 20 mg L-1 to 300 mg L-1.The degradation speed was related positively to initial inoculation amount.The optimal pH and aeration for the degradation were 8.0～9.0 and 100 ～250 mL,respectively.The temperature(between 25 ℃ and 42 ℃) had no notable effect on the degradation of carbofuran by CFDS-1.CFDS-1 could well degrade carbofuran not only in medium,but also in soil.