材料的微生物腐蚀

简要回顾了微生物对材料的腐蚀,列举了在石油、化工、电力、通讯及海洋工程中微生物腐蚀危害实例。指出参与腐蚀的菌有硫酸盐还原菌(SRB)、硫化菌、铁细菌、粘液形成菌和真菌。以参与硫铁元素循环的微生物,尤其是SRB为最重要。它们通过阴极去极化,形成氧浓差电池、腐蚀性代谢产物和破环保护膜等机制导致腐蚀。微生物腐蚀造成的损失十分惊人,参照英国NCS研究结果估算,目前我国微生物腐蚀造成的损失至少年达22亿元。可通过创造不利于菌生长环境,防护层,阴极保护和投加杀菌剂方法对微生物腐蚀进行控制。     

纳米银粒子印刷纳米电路，杀灭微生物

据报道，美国纽约州西部城市布法罗的纳米动力公司开发出可以用喷墨或传统印刷技术直接进行印刷的直径20nm的银粒子，可以广泛地用于各种基体，包括纸张、塑料等易弯曲材料。纳米银还在阻止物质表面的细菌、真菌、有害孢子和其它危险微生物的生长方面显示了卓越潜力，这些物质表面是传染病扩散的主要途径。可以将直径20nm的银粒子混入建筑用漆中，或涂在瓷砖、医疗器械、甚至石膏板表面，减缓或阻止有潜在危险的细菌和真菌的生长。     

公交客车空调铜、铝翅片散热器抑菌性能对比研究

通过公交客车空调铜、铝翅片散热器抑菌性能的比对、分析,比较车载空调铜制散热器与传统铝制散热器翅片表面的微生物水平及通过空调系统送风对车厢内空气质量的影响。在公交客车空调未投入使用期及投入使用末期对公交客车送风口、呼吸带空气及空调散热器翅片进行微生物采样检验,以公交客车停车场大气作为对照。与铝相比,铜作为表面材料能显著降低翅片表面细菌总数和真菌总数。空调采用铜翅片散热器可降低呼吸带空气中细菌总数的水平,具有显著的抑菌性能。     

油田污水中碳钢表面生物膜的生长监测与控制

金属表面硫酸盐还原菌微生物膜内的反应影响金属腐蚀的机理和速度,杀灭膜内微生物是控制微生物膜腐蚀金属的重要措施。采用丝束电极技术,研究了油田污水中生物膜在Q345碳钢表面的生长规律;通过投加3种杀菌剂来灭杀生物膜内细菌,并对其杀菌效果进行了比较,获得了杀菌剂对细菌的抑制周期及最低有效浓度。结果表明:油田污水中微生物首先在Q345碳钢表面大量附着、生长,至216 h时生长完整,至360 h时开始脱落;生物膜对Q345钢的腐蚀呈现不均匀性,微生物的存在可在局部范围内降低Q345碳钢表面的腐蚀电流密度,但有促进其腐蚀的倾向;杀菌剂HGY-B1的杀菌效果优于KD-24及LC-3,投添加量为300 mg/L时,对生物膜内细菌抑制周期可达8 d,最低杀菌浓度为40 mg/L。     

贪婪的微生物--如何防止板式热交换器受到腐蚀

时间没有蹂躏板式热交换器，相反是藻类。真菌或者细菌在作怪。本文即为用户提供一种微生物性工业腐蚀解决方案。     

Cl~-浓度对硫酸盐还原菌体系中316L不锈钢腐蚀行为的影响

油田采出水中Cl-含量是影响材料微生物腐蚀的重要因素,以往对此研究较少。通过电化学阻抗谱(EIS)、扫描电镜(SEM)、能谱(EDS)及荧光显微镜等研究了Cl-浓度分别为200,150,100,30,6 g/L的模拟油田采出水介质中硫酸盐还原菌(SRB)对316L不锈钢腐蚀行为的影响。结果表明:在30 g/L Cl-时316L不锈钢表面细菌附着量明显高于其他盐度,Cl-浓度高于100 g/L时不锈钢表面基本无细菌附着;在低盐度含SRB介质中,试样电荷转移电阻(Rct)较小,耐腐蚀性能较低;在低盐度下试样表面生物膜疏松多孔,有胞外聚合物、腐蚀产物和代谢产物形成,表面的Fe含量明显低于高盐度介质,而C含量较高,SRB的存在增大了试样的腐蚀溶解速度。     

几种材料的微生物腐蚀

用扫描电镜、电子探针等,研究了不锈钢、Ｑ２３０钢、工业纯铝、工业黄铜等材料对硫酸盐还原菌（ＳＲＢ）的腐蚀敏感性,结果表明Ｑ２３０钢易生长生物膜,其主要腐蚀产物为ＦｅＳ,以点蚀为主。不锈钢、工业纯铝等材料若有缺陷及残余应力处、有利于细菌生长,黄铜耐ＳＲＢ腐蚀。化学镀Ｎｉ－Ｐ和Ｎｉ－Ｍｏ－Ｐ可提高Ｑ２３０钢耐微生物腐蚀能力。     

生物膜对金属材料腐蚀性能影响的研究进展(上)

综述了生物膜对金属材料腐蚀的影响,内容包括:1)生物膜的形成;2)生物膜对材料腐蚀的影响;3)生物膜对阴极保护系统的影响;4)海洋极端微生物相关的腐蚀;5)微生物对航空、航天某些系统的影响;6)研究微生物腐蚀所采用的方法等。微生物相关的腐蚀在实际工程中对材料及设备的影响很大,因此,有必要深入开展研究并积极地采取防护措施。     

材料表面接枝聚乙二醇(PEG)刷的研究进展

聚乙二醇(PEG)刷能形成压制细菌靠近、产生排斥渗透力、降低聚合物链段运动性的高亲水性层,可阻止蛋白质的非选择性吸附以及减少细菌和微生物的粘接,可提高基质表面的防污能力,对金属而言亦可增加其缓蚀性能。本文综述了聚乙二醇刷在聚合物、硅基材料和金属等材料表面的应用,并提出了聚乙二醇(PEG)刷在未来应用于非生物金属材料防污及防腐等方面的可能性。     

金属材料的微生物腐蚀

谈到腐蚀,人们自然会想起金属材料的化学腐蚀或电化学腐蚀,而不大会想到金属材料的微生物腐蚀。然而,由近年来的研究表明,金属材料及其制品除了受到化学腐蚀或电化学腐蚀以外,还遭到微生物的腐蚀作用,而且,微生物对金属材料及其制品的腐蚀作用是相当大的。我们把工业领域中,由霉菌、细菌和酵母菌等微生物引起的工业材料及其制品的腐蚀、破坏作用叫做工业微生物灾害。     

Antimicrobial surfaces: a review of synthetic approaches,applicability and outlook

The rapid spread of microorganisms such as bacteria, fungi, and viruses can be extremely detrimental and can lead to seasonal epidemics or even pandemic situations. In addition, these microorganisms may bring about fouling of food and essential materials resulting in substantial economic losses. Typically, the microorganisms get transmitted by their attachment and growth on various household and high contact surfaces such as doors, switches, currency. To prevent the rapid spread of microorganisms, it is essential to understand the interaction between various microbes and surfaces which result in their attachment and growth. Such understanding is crucial in the development of antimicrobial surfaces. Here, we have reviewed different approaches to make antimicrobial surfaces and correlated surface properties with antimicrobial activities. This review concentrates on physical and chemical modification of the surfaces to modulate wettability, surface topography, and surface charge to inhibit microbial adhesion, growth, and proliferation. Based on these aspects, antimicrobial surfaces are classified into patterned surfaces, functionalized surfaces, superwettable surfaces, and smart surfaces. We have critically discussed the important findings from systems of developing antimicrobial surfaces along with the limitations of the current research and the gap that needs to be bridged before these approaches are put into practice.

     

Antimicrobial activity of transition metal acid MoO3 prevents microbial growth on material surfaces

Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H₂MoO₄), which is based on molybdenum trioxide (MoO₃). The modification of various materials (e.g. polymers, metals) with MoO₃ particles or sol-gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments.     

Characteristics of sulfide corrosion products on 316L stainless steel surfaces in the presence of sulfate-reducing bacteria

It has been found that microbial communities play a significant role in the corrosion process of steels exposed in aquatic and soil environments. Biomineralization influenced by microorganisms is believed to be responsible for the formation of corrosion products via complicated pathways of electron transfer between microbial cells and the metal. In this study, sulfide corrosion products were investigated for 316L stainless steel exposed to media with sulfate-reducing bacteria media for 7 weeks. The species of inorganic and organic sulfides in the passive film on the stainless steel were observed by epifluorescence microscope, environmental scanning electron microscope combined with energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The transformation from metal oxides to metal sulfides influenced by sulfate-reducing bacteria is emphasized in this paper.     

Life in oil: Hydrocarbon-degrading bacterial mineralization in oil spill-polluted marine environment

The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which an oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. This paper describes the three main processes of the Nakhodka oil spill, including: (1) the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years; (2) the laboratory-scale biodegradation of the Nakhodka oil spill over a 429-day period; and (3) the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill.Upon the slow evaporation of the Nakhodka oil spill during the 9-year weathering, the dendritic crystal growth of paraffin (a mixture of alkanes) occurred in the oil crust under natural conditions. Heavy metals were obtained in the original heavy oil samples of three seashores in the Sea of Japan. Si, S, Ti, Cr, Ni, Cu, and Zn were found in the original Nakhodka oil spill samples whereas these heavy metals and S were no longer present after 9 years. The anaerobic reverse side of the oil crust contained numerous coccus-type bacteria associated with halite. The hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation.A biodegradation process of heavy oil from the Nakhodka oil spill by indigenous microbial consortia was monitored over 429 days in the laboratory. The indigenous microbial consortia consisted of bacteria and fungi as well as the bacterium Pseudomonas aeruginosa isolated from Atake seashore, Ishikawa Prefecture, Japan. Both bacteria and fungi had a significant role in the observed biodegradation of heavy oil during the 429-day bioremediation with respect to the pH of the solution. Hydrocarbon-degrading bacteria had a tendency to play the greatest role under neutral to alkaline condition (pH; 7–7.8). On the contrary, when pH shifted to acidic (pH; 2–4) levels, the fungi took over to degrade heavy oil. During the period, the aliphatic hydrocarbons were reduced significantly but the aromatic hydrocarbons remained relatively constant even after 429 days of bioremediation.Experimental study was undertaken to investigate the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill. TEM/EDS imaging suggested that the clays present in oil-polluted seawater were capable of stimulating oil-degrading bacteria probably because Si from clays facilitates bacterial usage of oil and C-O-Na-Si complexes on the surfaces of bacterial cell walls are a stimulator for oil-degrading bacterial growth in seawater contaminated with the Nakhodka oil spill.     

Corrosion behavior of metals and alloys in marine-industrial environment

Abstract

This work deals with atmospheric corrosion to assess the degrading effects of air pollutants on ferrous and non-ferrous metals and alloys, which are mostly used as engineering materials. An exposure study was conducted in the Tuticorin port area located on the east coast of South India, in the Gulf of Mannar with Sri Lanka to the southeast. Common engineering materials, namely mild steel, galvanized iron, Zn, Al, Cu and Cu–Zn alloys (Cu–27Zn, Cu–30Zn and Cu–37Zn), were used in the investigation. The site was chosen where the metals are exposed to marine and industrial atmospheres. Seasonal 1 to 12 month corrosion losses of these metals and alloys were determined by a weight loss method. The weight losses showed strong corrosion of mild steel, galvanized iron, Cu and Zn and minor effect on Al and Cu–Zn alloys. Linear regression analysis was conducted to study the mechanism of corrosion. The composition of corrosion products formed on the metal surfaces was identified by x-ray diffraction and Fourier transform infrared spectroscopy.     

Corrosion behavior of metals and alloys in marine-industrial environment

This work deals with atmospheric corrosion to assess the degrading effects of air pollutants on ferrous and non-ferrous metals and alloys, which are mostly used as engineering materials. An exposure study was conducted in the Tuticorin port area located on the east coast of South India, in the Gulf of Mannar with Sri Lanka to the southeast. Common engineering materials, namely mild steel, galvanized iron, Zn, Al, Cu and Cu–Zn alloys (Cu–27Zn, Cu–30Zn and Cu–37Zn), were used in the investigation. The site was chosen where the metals are exposed to marine and industrial atmospheres. Seasonal 1 to 12 month corrosion losses of these metals and alloys were determined by a weight loss method. The weight losses showed strong corrosion of mild steel, galvanized iron, Cu and Zn and minor effect on Al and Cu–Zn alloys. Linear regression analysis was conducted to study the mechanism of corrosion. The composition of corrosion products formed on the metal surfaces was identified by x-ray diffraction and Fourier transform infrared spectroscopy.     

Life in oil: Hydrocarbon-degrading bacterial mineralization in oil spill-polluted marine environment

The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which an oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. This paper describes the three main processes of the Nakhodka oil spill, including: (1) the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years; (2) the laboratory-scale biodegradation of the Nakhodka oil spill over a 429-day period; and (3) the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill. Upon the slow evaporation of the Nakhodka oil spill during the 9-year weathering, the dendritic crystal growth of paraffin (a mixture of alkanes) occurred in the oil crust under natural conditions. Heavy metals were obtained in the original heavy oil samples of three seashores in the Sea of Japan. Si, S, Ti, Cr, Ni, Cu, and Zn were found in the original Nakhodka oil spill samples whereas these heavy metals and S were no longer present after 9 years. The anaerobic reverse side of the oil crust contained numerous coccus-type bacteria associated with halite. The hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation. A biodegradation process of heavy oil from the Nakhodka oil spill by indigenous microbial consortia was monitored over 429 days in the laboratory. The indigenous microbial consortia consisted of bacteria and fungi as well as the bacterium Pseudomonas aeruginosa isolated from Atake seashore, Ishikawa Prefecture, Japan. Both bacteria and fungi had a significant role in the observed biodegradation of heavy oil during the 429-day bioremediation with respect to the pH of the solution. Hydrocarbon-degrading bacteria had a tendency to play the greatest role under neutral to alkaline condition (pH; 7–7.8). On the contrary, when pH shifted to acidic (pH; 2–4) levels, the fungi took over to degrade heavy oil. During the period, the aliphatic hydrocarbons were reduced significantly but the aromatic hydrocarbons remained relatively constant even after 429 days of bioremediation. Experimental study was undertaken to investigate the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill. TEM/EDS imaging suggested that the clays present in oil-polluted seawater were capable of stimulating oil-degrading bacteria probably because Si from clays facilitates bacterial usage of oil and C-O-Na-Si complexes on the surfaces of bacterial cell walls are a stimulator for oil-degrading bacterial growth in seawater contaminated with the Nakhodka oil spill.     

金属表面有机疏水涂层的研究进展

金属表面涂覆有机涂层是防腐蚀、防氧化的重要途径,其疏水特性在制备自清洁表面等方面得到了广泛研究。综述了有机涂层在金属表面的应用以及金属表面的预处理方式,尤其是硅烷偶联剂的重要应用。同时介绍了材料表面的疏水性理论及疏水性研究的最新进展,并展望了有机涂层在金属表面的应用。     

Microbial community dynamics during composting of sewage sludge and straw studied through phospholipid and neutral lipid analysis

The composting process involves a succession of different communities of microorganisms that decompose the initial material, transforming it into a stable final product. In this work, the levels of phospholipid fatty acid (PLFA), neutral lipid fatty acid (NLFA) and sterol were monitored in compost versus time, as indicators of the activity of various microorganisms (Gram-positive or Gram-negative bacteria, fungi, etc.). During composting, the PLFA and NLFA from Gram-negative bacteria and eukaryotes (2-OH 10; 3-OH 12; 2-OH 14; 13:0; 16:1; 18:1 trans) as well as some sterols of plant origin (e.g. monostearin sterols) decreased until the end of composting. In contrast, the branched fatty acids with iso- and anteiso-forms (i-15:0; a-15:0; i-16; i-17) increased mainly in the thermophilic phase, but decreased right after. The PLFA 18:2 (6; 9), which is used as an index of the occurrence of some fungi, rose strongly at the beginning of composting, but fell after peak heating. In contrast, the other main sterol indicative of fungi, ergosterol, decreased at the beginning of the thermophilic phase, but increased strongly by the end of composting. Accordingly, cluster and PCA analysis separated the PLFA of Gram-negative bacteria and eukaryotic cells from those of Gram-positive bacteria and long-chain fatty acids. The fungal PLFA considered, 18:2 (9, 12), was clustered more closely to iso- and anteiso-branched PLFAs. Stigmasterol, squalene and cholesterol occurred in the lower right part of the loading plot and were clustered more closely to iso-, anteiso-branched PLFAs and 18:2 w 6,9 suggesting their relationship to microbial activities. We also observed the tendency of resistance of fatty acid PLFAs and NLFAs of long chain (19:0 (cis-9); 20:0) and some recalcitrant sterols, e.g. sitosterol, at the end of composting. The presence of high levels of the latter in the final stage indicates their contribution to the structural stability of organic matter fractions. These recalcitrant components were more clustered and occurred in the lower right part of the loading plot.     

Lectin and carbohydrate affinity capture surfaces for mass spectrometric analysis of microorganisms

In a preliminary report (Bundy, J. L.; Fenselau, C. Anal. Chem 1999, 71, 1460-1463), we demonstrated the use of lectin-derivatized surfaces to capture and concentrate complex carbohydrates as well as microorganisms from sample matrixes unamenable to direct MALDI mass spectrometry. Here, we extend the work to include samples representative of a wider variety of microorganisms of importance to human health and of enveloped viruses. In this study, lectins were immobilized directly to a membrane surface via primary amines. A complementary approach was also explored, using immobilized carbohydrates to capture bacteria via microbial lectins expressed on their surfaces. The carbohydrate-based surfaces were constructed by first immobilizing streptavidin to the membrane, followed by attachment of a commercially produced biotin/carbohydrate polymer. Acid treatment of the sample prior to mass spectrometric analysis permits the observation of protein biomarkers from the captured microbial samples in the 5-20 kDa mass range. Bacteria samples were detected from physiological buffers, urine, milk, and processed chicken samples using the biocapture probes. Viral samples were detected from culture based on glycoprotein moieties desorbed directly from the surface. The carbohydrate-based system provided greater sensitivity than the lectin system, possibly due to the larger number of accessible saccharide ligands on the polymer.