Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, National Demonstration Center for Experimental Water Environment Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, National Demonstration Center for Experimental Water Environment Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Sci Total Environ. 2020 May 20;718:136679. doi: 10.1016/j.scitotenv.2020.136679. Epub 2020 Jan 15.
At present, the researches on the corrosion of mixed microorganisms pay more attention to iron-oxidizing bacteria (IOB) and sulfate-reducing bacteria (SRB) in tap water or seawater. Pseudomonas fluorescens and Escherichia coli are two common microorganisms in reclaimed water, but there are few studies about their interaction on metal interface and about their influence on metal corrosion behavior. The corrosion behavior of carbon steel under mixed microorganisms of Escherichia coli and Pseudomonas fluorescens was studied by corrosion weight loss, electrochemistry, scanning electron microscopy (SEM) and X-ray diffraction (XRD) in this paper. The dominant bacteria under mixed bacteria conditions determined the final result of corrosion reaction in reclaimed water. On the first three days, the dominant strain was Escherichia coli, which produced acid on the surface of carbon steel and deteriorated corrosion. After the 3rd day, the dominant strain was Pseudomonas fluorescens, which inhibited the growth of Escherichia coli and slowed down corrosion. When the extracellular polymeric substances (EPS) concentration of Pseudomonas fluorescens reached 400 mg/L, it would inhibit the growth and reproduction of Escherichia coli. On the contrary, Escherichia coli EPS acted as a nutrient for Pseudomonas fluorescens, promoting the growth and reproduction of Pseudomonas fluorescens.
目前，混合微生物腐蚀的研究主要集中在自来水中或海水中的氧化铁（IOB）和硫酸盐还原菌（SRB）。荧光假单胞菌和大肠杆菌是再生水中两种常见的微生物，但关于它们在金属界面上的相互作用以及对金属腐蚀行为的影响的研究较少。本文通过腐蚀失重、电化学、扫描电子显微镜（SEM）和 X 射线衍射（XRD）研究了大肠杆菌和荧光假单胞菌混合微生物对碳钢的腐蚀行为。在再生水中，混合细菌条件下的优势细菌决定了腐蚀反应的最终结果。在前三天，优势菌是大肠杆菌，它在碳钢表面产酸，使腐蚀恶化。第 3 天以后，优势菌是荧光假单胞菌，它抑制了大肠杆菌的生长，减缓了腐蚀。当荧光假单胞菌的胞外聚合物（EPS）浓度达到 400mg/L 时，它会抑制大肠杆菌的生长和繁殖。相反，大肠杆菌 EPS 则成为荧光假单胞菌的营养物质，促进了荧光假单胞菌的生长和繁殖。
