Abstract: In order to get strains degrading pyrene, which can produce extracellular catechol-2,3-dioxygenase, oil-contaminated soil samples in Karamay of Xinjiang were taken as specimen sources, strains with polycyclic aromatic hydrocarbon were screened using pyrene as the sole carbon and energy source. Testing the extracellular catechol-2,3-dioxygenase the strain produced qualitatively and quantitatively by chromogenic reaction and enzymatic reaction. And the strain was identified according to its morphological characteristics, BIOLOG GENⅢ microplate identification and 16S rRNA gene sequence analysis. Based on single factor and orthogonal experiments, preliminary discussion on the growth characteristics and the best degradation conditions of the strain were carried out. The results showed that strain W39 degrading pyrene could secrete extracellular catechol-2,3-dioxygenase, and after being induced by pyrene, the enzyme producing capacity was increased by 3 times. Strain W39 was identified as Enterobacter cloacae. Its optimum culture conditions was 35℃, pH 7.0, and 50 mg/L pyrene. Therefore, catechol-2,3-dioxygenase is one of the key enzymes in the process of pyrene degradation, and further studies can be conducted on it.

Key words: catechol-2,3-dioxygenase, strain screening, BIOLOG identification system, Enterobacter cloacae

摘要： 为了筛选得到一株产胞外邻苯二酚-2,3-双加氧酶的芘降解菌株，以新疆克拉玛依石油污染土壤为样品源，采用芘平板升华法，筛选具有多环芳烃降解能力的菌株。利用显色反应及酶促反应对菌株所产胞外邻苯二酚-2,3-双加氧酶进行定性定量试验并对其进行形态学观察、BIOLOG GENⅢ微孔板鉴定及16S rRNA序列分析。通过单因子影响试验和正交试验对菌株的生长特性及最佳降解条件进行了初步探讨。结果表明：芘降解菌株W39能分泌胞外邻苯二酚-2,3-双加氧酶，且经芘诱导后，产酶能力提高了3倍；经鉴定，菌株W39为阴沟肠杆菌（Enterobacter cloacae）；最适培养条件：35℃，pH 7.0，芘浓度50 mg/L。可见，邻苯二酚-2,3-双加氧酶是降解芘的关键酶之一，可对其进行进一步研究。

关键词: 邻苯二酚-2,3-双加氧酶, 菌种筛选, BIOLOG鉴定系统, 阴沟肠杆菌