铜绿假单胞细菌对海洋钢铁材料微生物腐蚀机理的研究

For marine steel materials，the marine microbiologically influenced corrosion (MMIC) is regarded as a knotty problem. It is widely accepted that the biofilm is the main factor that contributes to MIC. Currently, most of the researches are focused on MIC caused by anaerobic bacteria such as sulfate-reducing bacteria (SRB), while the aggressive aerobes that can cause severe MIC attack are fully neglected. Marine Pseudomonas aeruginosa is reported to be the pioneer colonizer of the biofilm, and possesses strong corrosivity in the marine environment. To our best knowledge, the MIC mechanism of Pseudomonas aeruginosa is still unclear. In the study, the gene knockout technique will be employed to knockout the most important genes phzM and nadE in the electron transfer chain of Pseudomonas aeruginosa to confirm their roles in the corrosion process of Pseudomonas aeruginosa. The phzM and nadE genes are very likely to regulate the production of pyocyanin, which is an important electron shuttle in the MIC due to Pseudomonas aeruginosa. This is the first time that the MIC mechanism of Pseudomonas aeruginosa is studied from the aspect of molecular biology level, and the electrochemical noise (EN) will be used in this study to accurately investigate the MIC behavior of Pseudomonas aeruginosa. This study may help to elucidate the MIC mechanism of marine steel materials, more important, the genes that confirmed to regulate the MIC of Pseudomonas aeruginosa can be the potential targets for the novel MIC mitigation methods.

对于海洋工程用钢铁材料而言，海水中的微生物腐蚀一直是世界公认的难题。目前，生物膜被认为是导致微生物腐蚀的主要原因，人们普遍重视厌氧细菌（如硫酸盐还原菌）的微生物腐蚀，而忽视了具有很强腐蚀性的好氧腐蚀细菌。海洋铜绿假单胞细菌既是形成生物膜的先导细菌，也是具有很强的腐蚀性，但目前关于这种细菌的微生物腐蚀机理尚不清楚。本项目拟采用基因敲除技术，通过敲除调控电子载体绿脓菌素（pyocyanin，PYO）的重要基因phzM和nadE，来确定这2个基因是否调控绿脓菌素的合成，从而调控铜绿假单胞细菌对海洋钢铁材料的腐蚀。本研究首次从分子生物学水平研究铜绿假单胞细菌的微生物腐蚀的机理，并采用电化学噪声准确表征铜绿假单胞细菌的微生物腐蚀。该研究不仅能够有助于进一步阐明海洋钢铁材料微生物腐蚀的电子传递机制，更重要的是可以利用该机制寻找抑制海洋微生物腐蚀的新靶点和新方法。

对于海洋工程用钢铁材料而言，海水中的微生物腐蚀一直是世界公认的难题。目前，生物膜被认为是导致微生物腐蚀的主要原因，人们普遍重视厌氧细菌（如硫酸盐还原菌）的微生物腐蚀，而忽视了具有很强腐蚀性的好氧腐蚀细菌。海洋铜绿假单胞细菌既是形成生物膜的先导细菌，也是具有很强的腐蚀性，但目前关于这种细菌的微生物腐蚀机理尚不清楚。通过生物合成学技术从微观尺度（基因水平）证明了phzH/M/S等基因所编码的吩嗪类化合物是调控海洋铜绿假单胞菌腐蚀的细胞外电子载体并调控整个微生物腐蚀的进程，阐明了海洋铜绿假单胞菌的微生物腐蚀机理。首次从基因水平证明了细胞外电子传递是调控微生物腐蚀的最关键因素，从而将微生物腐蚀的机理研究提升到分子水平，为研究电活性微生物的腐蚀机理奠定了理论基础，同时为微生物腐蚀的检测提供了新思路。