Genome shuffling improves degradation of the anthropogenic pesticide pentachlorophenol by Sphingobium chlorophenolicum ATCC 39723
Genome shuffling improves degradation of the anthropogenic pesticide pentachlorophenol by Sphingobium chlorophenolicum ATCC 39723
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DOI：
10.1128/aem.70.4.2391-2397.2004
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发表时间：
2004-04-01
影响因子：
4.4
通讯作者：
Copley, SD
中科院分区：
文献类型：
--
作者：
Dai, MH;Copley, SD
五氯酚（PCP）是一种高毒性的人为农药，从PCP污染土壤中分离的革兰氏阴性菌Sphingobium chlorophenolicum可将PCP矿化。但五氯酚降解缓慢，S.氯苯酚不能耐受高浓度的五氯苯酚。我们利用基因组改组技术提高了S.氯酚我们已经获得了几种菌株，降解PCP更快，耐受更高水平的PCP比野生型菌株。第三轮改组后获得的几种菌株可以生长在四分之一强度胰蛋白酶大豆肉汤板含有6至8 mM PCP，而原始菌株不能生长在PCP的存在下，浓度高于0.6 mM。一些突变体能够完全降解3 mM PCP在四分之一强度胰蛋白酶大豆肉汤，而没有降解可以实现由野生型菌株。对几种改良菌株的分析表明，改良的表型是由于各种突变的组合导致生长速度加快、五氯苯酚降解基因的组成型表达以及对五氯苯酚及其代谢物毒性的抗性增强。
Pentachlorophenol (PCP), a highly toxic anthropogenic pesticide, can be mineralized by Sphingobium chlorophenolicum, a gram-negative bacterium isolated from PCP-contaminated soil. However, degradation of PCP is slow and S. chlorophenolicum cannot tolerate high levels of PCP. We have used genome shuffling to improve the degradation of PCP by S. chlorophenolicum. We have obtained several strains that degrade PCP faster and tolerate higher levels of PCP than the wild-type strain. Several strains obtained after the third round of shuffling can grow on one-quarter-strength tryptic soy broth plates containing 6 to 8 mM PCP, while the original strain cannot grow in the presence of PCP at concentrations higher than 0.6 mM. Some of the mutants are able to completely degrade 3 mM PCP in one-quarter-strength tryptic soy broth, whereas no degradation can be achieved by the wild-type strain. Analysis of several improved strains suggests that the improved phenotypes are due to various combinations of mutations leading to an enhanced growth rate, constitutive expression of the PCP degradation genes, and enhanced resistance to the toxicity of PCP and its metabolites.