一株高效降酚菌的质粒特性及柠檬酸细菌表达的研究

Studies of One Phenol-degrading Bacteria,the Degradative Plasmids and Citrobacter expression Expression of a Phenol-degrading Bacterium

在焦化废水处理厂的活性污泥中筛选的降酚效果较好的菌株H,研究其质粒特性并提取其降解质粒将其转入柠檬酸细菌进行表达。结果表明H菌株具有质粒,且质粒片段较大最大的超过10 kb,最小的2 kb左右。通过SDS和原生质体再生法分别对H菌进行质粒消除,结果发现质粒去除的菌株降酚能力也随之消失。说明H菌株的质粒上有控制酚降解基因存在;提取H菌的质粒将其转入柠檬酸细菌进行表达,获得了转化子。转化子具有较好的降酚效果12 h可达77.34%,但转化子的降解速率较小。另证明了转化子内含有与H菌株相同特性的质粒得到具有降酚能力的柠檬酸细菌表达体系。

The phenol-degrading bacteria was isolated from coking wastewater treatment plant＇ s activated sludge. The strain with highest phenol-degradating ability was choosed and extracted its degradation plasmid into Citrobacter to express. Plasmid were extracted from the high phenol-degrading bacteria strains H . The largest plasmid was more than 10 kb and the smallest about 2 kb. Plasmids of H were eliminated through SDS and protoplast regeneration respectively and the results showed that capacity of H disappeared with removal of plasmid, so phenol-degradating gene was mapping in the plasmid preliminaryly. The plasmid extracted from H transformed into E. coli to express and obtained transformants. The results of phenol-degradating capacity test results showed that transformants got better results phenol degradation ratio was 77.34 % in 12 h, but still was than H, which may be related to copies of the plasmidthe transformants contained. And it also proved transformants obtained the plasmid with the same characteristics as H.