biodegradation of chlorpyrifos and its hydrolysis product 3,5,6-trichloro-2-pyridinol by a new fungal strain cladosporium cladosporioides hu-01生物降解毒死蜱及其水解产物3,5,由一个新的真菌菌株6-trichloro-2-pyridinol枝孢属cladosporioides hu-01.pdfVIP

Biodegradation of Chlorpyrifos and Its Hydrolysis Product 3,5,6-Trichloro-2-Pyridinol by a New Fungal Strain Cladosporium cladosporioides Hu-01 Shaohua Chen.¤, Chenglan Liu., Chuyan Peng, Hongmei Liu, Meiying Hu, Guohua Zhong* Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou, People’s Republic of China Abstract Intensive use of chlorpyrifos has resulted in its ubiquitous presence as a contaminant in surface streams and soils. It is thus critically essential to develop bioremediation methods to degrade and eliminate this pollutant from environments. We present here that a new fungal strain Hu-01 with high chlorpyrifos-degradation activity was isolated and identified as Cladosporium cladosporioides based on the morphology and 5.8S rDNA gene analysis. Strain Hu-01 utilized 50 mg?L21 of chlorpyrifos as the sole carbon of source, and tolerated high concentration of chlorpyrifos up to 500 mg?L21. The optimum degradation conditions were determined to be 26.8uC and pH 6.5 based on the response surface methodology (RSM). Under these conditions, strain Hu-01 completely metabolized the supplemented chlorpyrifos (50 mg?L21) within 5 d. During the biodegradation process, transient accumulation of 3,5,6-trichloro-2-pyridinol (TCP) was observed. However, this intermediate product did not accumulate in the medium and disappeared quickly. No persistent accumulative metabolite was detected by gas chromatopraphy-mass spectrometry (GC-MS) analysis at the end of experiment. Furthermore, degradation kinetics of chlorpyrifos and TCP followed the first-order model. Compared to the non-inoculated controls, the half-lives (t1/2) of chlorpyrifos and TCP significantly reduced by 688.0 and 986.9 h with the inoculum, respectively. The isolate harbors the metabolic