Abstract: In order to obtain phthalic acid esters (PAEs) biodegradation strain, a bacterial strain capable of growing with PAEs as the sole carbon source and energy was selected from contaminated soil and named as SD2. The 16S rDNA obtained by PCR amplification and the construction of molecular phylogeny trees can be identified as Tsukamurella sp. The degradation of DBP under different temperature, pH value, and rotational speed conditions was investigated. The degradation ability of the strain to DBP was determined by high performance liquid chromatography. The results showed that the optimum degradation condition of SD2 is temperature of 30℃, pH value of 9 and rotational speed of 150 r/min. Under this optimum condition, SD2 can completely degrade 500 mg/L DBP within 72 h. The intermediate metabolites, butylmethyl phthalate and phthalic acid, were detected by GC-MS during the degradation of DBP, and phthalic acid could be further completely degraded into CO2 and H2O. To our knowledge, this is the first report about the biodegradation of PAEs by genus Tsukamurella.
Key words: Tsukamurella; dibutyl phthalate; biodegradation; 16S rDNA; organic pollutants