Study on the Isolation,Identification and Degradation Characters of Strain 2D-1 for Degrading DDT

A Gram positive bacterium strain 2D-1 for degrading DDT effectively was isolated from the swampy sludge of Hongze Lake.According to its physiological biochemical characters and the homology analysis of its 16S rDNA sequence,this strain was identified as Bacillus cereus.This strain could degrade 95.64% DDT(total concentration of DDT of 53.46 mg/L) in inorganic salt yeast cream liquor medium within 8 days under the conditions of 5% inoculation quantity,150 r/min,33 ℃ and pH 6.5.The absolute degradation concentrations of p,p′-DDT,p,p′-DDE,p,p′-DDD and o,p′-DDT were 5.32,22.98,6.66 and 16.17 mg/L respectively.The results showed that the adaptability of strain 2D-1 to four kinds of DDT isomers was different and p,p′-DDE was the optimum substrate for strain 2D-1.Six kinds of main products would be produced after DDT degradation by 2D-1.