Abstract：DDT was used as the target pollutant, and a strain capable of degrading DDT was obtained by isolation and the identification of the strain was carried out through morphological observation, experiments on physiological and biochemical characteristics and 16S rRNA sequencing. The strain was identified as Methylovorus, and named as Methylovorus sp. XLL03. The best growing condition for the strain was as follow:pH of 7, 30℃, external carbon source concentration of 0.5%, and initial DDT concentration of 20mg/L. The best degradation condition for the strain was as follow:pH of 6, 30℃, external carbon source(glucose) concentration of 0.1%, and initial DDT concentration of 20mg/L. Under the optimized conditions, the highest degradation rate of DDT by strain XLL03 was 50.4% 4 days later. The qualitative analysis of degradation intermediates of DDT was carried out by GC-MS. It was initially concluded that DDT could first be transformed into DDD and DDE via dechlorination and dehydrochlorination respectively, subsequently both DDD and DDE converted to DDMU by further dechlorination, and then after ring opened, DDMU went through a series of reactions was completely mineralized. No metabolic intermediates was found during the metabolism of DDT, which indicating that strain XLL03 has potential application prospects in repairing DDT-contaminated water or soil.
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