中文摘要：

芳香烃降解菌是石油污染土壤修复的主要生物资源。采用芘平板升华法对克拉玛依原油污染土壤样品进行驯化培养,分离得到一株芘降解菌B2,经16S rDNA基因序列比对及系统发育进化分析表明,该菌株为假单胞菌属（Pseudo-monas）。采用正交设计方法优化菌株B2对高分子量多环芳烃芘的降解条件,并构建多元非线性模型预测菌株B2对芘的最佳降解条件,结果表明：在接种量OD660 nm为0.60、降解温度为40℃、降解时间为6.0 d时,预测菌株B2对芘的降解最大达到38.214 mg/L,实际测得最大降解量为37.906 mg/L,预测准确率为99.19%。运用PCR技术克隆B2的邻苯二酚-2,3-双加氧酶基因（B2C23O）（I.2.A亚家族）,核酸序列分析表明,该基因全长880 bp,具有一个完整的开放阅读框,编码246个氨基酸,与已报道的Pseudomonas putida W619同源性最高为97%;对B2C23O基因编码氨基酸序列进行分析,发现其具有邻位断裂双加氧酶模式结构,推测菌株B2通过邻位裂解途径降解芘代谢中间产物邻苯二酚。

英文摘要：

Polycyclic aromatic hydrocarbons degradation bacteria from oil-contaminated soils are the main biological resources for bioremediation.Using pyrene as the sole carbon and energy source and agar plate subliming method,a strain named B2 was isolated from oil-contaminated soil samples in Karamay,China.Based on 16S rDNA gene sequence homology and phylogenetic analysis,B2 was identified as genus Pseudomonas with highest similarity（99%）.Orthogonal design method was used to optimize the degradation conditions of the pyrene,and multi-nonlinear model was constructed to predict optimal degradation conditions.It showed that the optimal degradation conditions for pyrene was 38.214 mg/L in 6 days at the inoculumsize of OD660 nm at 0.6 and degradation temperature at 40℃.The verified experiment showed that the actual maximum degradation capacity was 37.906 mg/L,and predicted accuracy rate approached 99.19%.Then,the gene which encoding the catechol-2,3-dioxygenase named B2C23O（I.2.A subfamily） was cloned by PCR method.Sequence analysis showed that the full length of the gene was 880 bp containing a complete ORF and encoded 246 amino acids.The gene was closest to the P.putia W619 with similarity of 97%.Predicting the secondary structure of the enzyme protein was based on analysis of the nucleic acid sequence.Analysis of genes encoding amino acid showed that pyrene metabolism of strain B2 is ortho-cleavage pathway.