Abstract：
Bacterial communication interruption based on quorum quenching (QQ) has been proven its potential in biofilm formation inhibition and biofouling control. However, it would be more satisfying if QQ could be combined with the efficient degradation of contaminants in environmental engineering. In this study, we engineered a biofilm of Pseudomonas putida through introducing a QQ synthetic gene, which achieved both biofilm formation inhibition and efficient degradation of benzene series in wastewater. The aiiO gene introduced into the P. putida by heat shock method was highly expressed to produce QQ enzyme to degrade AHL-based signal molecules. The addition of this engineered P. putida reduced the AHLs concentration, quorum sensing gene expression, and connections of the microbial community network in activated sludge and therefore inhibited the biofilm formation. Meanwhile, the sodium benzoate degradation assay indicated an enhanced benzene series removal ability of the engineering bacteria on activated sludge. Besides, we also demonstrated a controllable environmental risk of this engineered bacteria through monitoring its abundance and horizontal gene transfer test. Overall, the results of this study suggest an alternative strategy to solve multiple environmental problems through genetic engineering means and provide support for the application of engineered bacteria in environmental biotechnology.
摘要：
基于群体猝灭（QQ）的细菌通讯中断已被证明具有抑制生物膜形成和控制生物污染的潜力。然而,如果QQ能与环境工程中污染物的有效降解相结合，将会更加令人满意。在这项研究中,我们通过引入QQ合成基因设计了恶臭假单胞菌的生物膜，既实现了生物膜的形成抑制,又实现了废水中苯系物的高效降解。通过热休克法导入恶臭假单胞菌的aiiO基因被高表达，产生QQ酶降解基于AHL的信号分子。添加这种工程恶臭假单胞菌降低了AHLs浓度，群体感应基因表达，以及活性污泥中微生物群落网络的连接，因此抑制了生物膜的形成。同时,苯甲酸钠降解实验表明，工程菌对活性污泥的苯系物去除能力增强。此外,我们还通过监测这种工程细菌的丰度和水平基因转移测试，证明了其可控的环境风险。总的来说,这项研究的结果提出了通过基因工程手段解决多重环境问题的替代策略，并为工程细菌在环境生物技术中的应用提供了支持。
