Construction of effective PCB-degradation bioreactor by modification of regulatory system of PCB-degrading bacterium using genetic engineering.

多氯联苯降解菌假单胞菌的BPH操纵子加入联苯可诱导表达KKS102。在BPH操纵子下游发现了一个氨基酸序列与LysR型调节子相似的基因，命名为bphR。bphR基因的突变对BPH操纵子的诱导表达没有影响，表明bphR不是BPH操纵子的调节子。构建了4种BPH基因的干扰物(bphA、bphB、bphC和bphD)。当加入联苯时，bphA、bphB和bphC干扰物没有显示出诱导bphE基因表达的能力。而bphD干扰物则表现出诱导性。这些结果表明，BPH操纵子的直接诱导物不是联苯，而是由BPhA、BphB和BPhC从联苯产生的偏裂化合物。在本研究中，我们发现了BPH操纵子在KKS1O2中的一种新的调控机制。我们认为，我们的发现将能够应用于降解多氯联苯的生物反应器的改造。

The bph operon of PCB-degraging bacterium, Pseudomonas sp. KKS102 was inducibly expressed by addition of biphenyl. A gene whose deduced amino acid sequence shows similarity to the LysR-type regulator was found just downstream of the bph operon, and named it bphR.The disruption of the bphR gene had no effect on the inducible expression of the bph operon, indicating that the bphR is not a regulator of the bph operon. Four disruptants of bph genes (bphA, bphB, bphC, and bphD) were constructed. The bphA, bphB, and bphC disruptants did not show the inducibility of the bphE gene expression when biphenyl was added. Whlie, the bphD disruptant showed the inducibility. These results indicated that the direct inducer of the bph operon is not biphenyl but meta-cleavage compound which is produced by BphA, BphB, and BphC from biphenyl. Furthermore, cis-element locating just upstream of the bphE gene for a response of biphenyl was identified.In this study, we revealed a novel regulation mechanism of the bph operon in KKS1O2. We consider that our finding will be able to be applied for the modification of the PCB-degrading bioreactor.