Microbial Corrosion Research Articles

Controlling the Impact of Bentonite Microbial Communities in Disposal of Radioactive Wastes

Disposal in a geological disposal facility (GDF) is the preferred route for the world’s growing inventory of nuclear wastes. Bentonite clay is a common component of the engineered barrier system, serving to isolate and stabilise the high heat-generating waste packages in the geosphere (Stroes-Gascoyne et al. 2010). Bentonites naturally contain sulfate-reducing bacteria (SRB) (Haynes et al. 2021), which in the presence of the correct substrates, produce H2S that is highly corrosive to metals (such as steel waste packages). Sulfate, the electron acceptor, is present in most groundwaters, and the corrosion of steel produces hydrogen, an electron donor (Bagnoud et al. 2016). Compacting bentonite on deposition can restrict GDF microbial activity, since swelling pressures upon saturation restrict the available porosity for microbes (Masurat et al. 2010). Additionally, groundwater chemical conditions may impact bentonite mechanical properties (e.g., the effect of salinity on swelling capacity (He et al. 2019), and the energetics of bacterial metabolism (Oren 1999). This work uses bentonite SRB enrichment cultures to assess parameters that control microbial metabolism, and the relative contribution of microbially influenced corrosion (MIC), versus chemical corrosion of steel (Fig. 1). This will provide evidence to underpin lines of argument and models used in the safety assessments for geological disposal. Experiments described include microcosm incubations containing bentonite slurries across a range of salinity, and pressure cell bioreactors to evaluate the above conditions in the context of a compacted bentonite barrier system. Initial results show that in the presence of lactate as an electron donor, slurry systems with bentonite, low-carbon steel and sulfate-containing groundwater provide the essential nutrients for the proliferation of an MIC-inducing community (Fig. 2). Experiments have also shown that in such systems, increasing the groundwater NaCl concentration inhibits microbial activity during the 3-month experimental duration. Additionally, SRB have been shown to reduce priority radionuclides, such as selenium (Nancharaiah and Lens 2015). Selenium is a priority radionuclide in high-level waste, and in its highest oxidation states, selenate (Se(VI)) and selenite (Se(IV)), it is highly soluble and therefore mobile in the environment. Early experiments have shown that when an electron donor is present in microcosms containing bentonite and groundwater, bentonite-native SRB may be capable of reducing soluble selenium down to insoluble Se(0), restricting its environmental mobility.

Distribution mechanism of dominant genera and species of bacteria under different river velocity

Flow velocity as the basic hydrodynamic condition significantly affects bacterial proliferation and biofilm formation, yet how different flow velocity influences the attachment and distribution of dominant bacteria in different ecological types is poorly understood. In this work, We collected samples from the bottom, side walls and water samples at the flow rates of 0.794m/s and 0.538m/s, respectively. Through high-throughput sequencing identification and analysis technology, it was found that the composition abundance of Acinetobacter and Psychrobacter, as dominant bacteria, could reach 70%-80% in the floating state, and the attached bacteria at low flow rates were about 20% higher than those at high flow rates. The results showed that the high flow rate inhibited the attachment behavior of dominant bacteria and changed the species composition structure in the overlapping area of multiple samples, which provided a new direction for the prevention and control of microbial corrosion and pollution in waters.

Burning question: Are there sustainable strategies to prevent microbial metal corrosion?

The global economic burden of microbial corrosion of metals is enormous. Microbial corrosion of iron-containing metals is most extensive under anaerobic conditions. Microbes form biofilms on metal surfaces and can directly extract electrons derived from the oxidation of Fe0 to Fe2+ to support anaerobic respiration. H2 generated from abiotic Fe0 oxidation also serves as an electron donor for anaerobic respiratory microbes. Microbial metabolites accelerate this abiotic Fe0 oxidation. Traditional strategies for curbing microbial metal corrosion include cathodic protection, scrapping, a diversity of biocides, alloys that form protective layers or release toxic metal ions, and polymer coatings. However, these approaches are typically expensive and/or of limited applicability and not environmentally friendly. Biotechnology may provide more effective and sustainable solutions. Biocides produced with microbes can be less toxic to eukaryotes, expanding the environments for potential application. Microbially produced surfactants can diminish biofilm formation by corrosive microbes, as can quorum-sensing inhibitors. Amendments of phages or predatory bacteria have been successful in attacking corrosive microbes in laboratory studies. Poorly corrosive microbes can form biofilms and/or deposit extracellular polysaccharides and minerals that protect the metal surface from corrosive microbes and their metabolites. Nitrate amendments permit nitrate reducers to outcompete highly corrosive sulphate-reducing microbes, reducing corrosion. Investigation of all these more sustainable corrosion mitigation strategies is in its infancy. More study, especially under environmentally relevant conditions, including diverse microbial communities, is warranted.

Active bacterial anti-adhesion strategy based on directional transportation of droplet self-actuated by Laplace pressure gradient on self-actuated and infrared sensing responsive platform

The adhesion of adverse bacteria to material surfaces increases the risk of microbial corrosion and bacterial transmission. Superhydrophobic and superhydrophilic-type bacterial anti-adhesion approaches have been explored; however, these approaches are static and passive. This study proposes an active-bacterial anti-adhesion strategy based on the directional transportation of bacterial droplets on a star-shaped intelligent response platform (SIRP) for droplet self-actuation. Bacteria and other droplets can self-actuate on the SIRP, where droplets are in a superhydrophobic Cassie–Baxter wetting state, owing to the generated Laplace pressure gradient force on the wedge-shaped groove and extremely small adhesion resistance. The velocity and distance travelled of self-actuated droplets depend on various factors such as the opening angle, etching depth of the wedge-shaped groove, modified perfluorodecyltrimethoxysilane density, and droplet volume. Experimental and finite element simulation results confirm the continuous increase and sharp decrease in Laplace pressure difference in the self-actuated and non-self-actuated zones, respectively. The SIRP demonstrates superior bacterial anti-adhesion during bacterial droplet self-actuation and a very smart infrared-sensing sterilization or micro-reaction response to different types of droplets. The SIRP not only opens a new avenue for active bacterial anti-adhesion strategies but also offers a promising application for smart controllable micro-reactions.

Corrosion behavior of 7B04 aluminum alloy under the synergistic effect of Lacticaseibacillus paracasei and Acinetobacter lwoffi

Microbially influenced corrosion (MIC) is a multifaceted phenomenon that is influenced by the synergistic activity of various bacterial species that thrive within biofilms. The present study aims to investigate the impact of interspecies relationships on the corrosion behavior of aluminum alloy (Al alloy). To achieve this, cultures of Lacticaseibacillus paracasei (L. paracasei) and Acinetobacter lwoffi (A. lwoffi) were mixed and analyzed. The electrochemical experimental findings indicated that the 7B04 Al alloy exhibited the lowest Rct value and the highest corrosion current density when immersed in the mixed system. The utilization of surface analysis techniques, such as scanning electron microscopy and stereomicroscope, had led to the discovery of a significant number of corrosion pits in the mixed system. This finding suggested that the corrosion phenomenon was more severe than previously anticipated. The growth curve analysis revealed a synergistic interaction among the mixed bacterial species. The co-cultivation of A. lwoffi and L. paracasei resulted in increased growth activity of L. paracasei in comparison to its growth in a single system. The occurrence of dominant colonies and the development of biofilms were identified as the primary factors contributing to localized corrosion. Furthermore, the combined action of the two bacterial strains exhibited a synergistic effect that exacerbated the corrosion process.

Corrosion Types and Measures for Petrochemical Equipment

The corrosion problem of petrochemical equipment has always been one of the important factors restricting industrial development. Starting from the basic concept of corrosion, this article delves into various forms of corrosion in petrochemical equipment and their impact on equipment performance. Chemical corrosion, high-temperature corrosion, microbial corrosion, and stress corrosion are common forms of corrosion in petrochemical equipment, exacerbating equipment aging and wear. For different forms of corrosion, existing anti-corrosion measures include material selection, coating protection, electrochemical protection, etc. However, these measures also face certain limitations and challenges in practical applications. In summary, this article deeply analyzes the corrosion problem of petrochemical equipment, summarizes the limitations of existing anti-corrosion measures, and explores key measures to improve the anti-corrosion performance of petrochemical equipment. These research results are expected to provide useful references for equipment maintenance and safe operation in the petrochemical industry, and contribute to solving corrosion problems and improving equipment service life.

Microorganisms Involved in the Biodegradation and Microbiological Corrosion of Structural Materials

Microbiologically influenced corrosion (MIC) is the process of material degradation in the presence of microorganisms and their biofilms. This is an environmentally assisted type of corrosion, which is highly complex and challenging to fully understand. Different metallic materials, such as steel alloys, magnesium alloys, aluminium alloys, and titanium alloys, have been reported to have adverse effects of MIC on their applications. Though many researchers have reported bacteria as the primary culprit of microbial corrosion, several other microorganisms, including fungi, algae, archaea, and lichen, have been found to cause MIC on metal and non-metal surfaces. However, less attention is given to the MIC caused by fungi, algae, archaea, and lichens. In this review paper, the effects of different microorganisms, including bacteria, fungi, algae, archaea, and lichens, on the corrosion properties of engineering materials have been discussed in detail. This review aims to summarize all of the corrosive microorganisms that directly or indirectly cause the degradation of structural materials. Accusing bacteria of every MIC case without a proper investigation of the corrosion site and an in-depth study of the biofilm and secreted metabolites can create problems in understanding the real cause of the materials’ failure. To identify the real corrosion agent in any environment, it is highly important to study all kinds of microorganisms that exist in that specific environment.

Influence of grain size and crystallographic orientation on microbially influenced corrosion of low-carbon steel in artificial seawater

How the microstructure of steel affects a material’s response to microbially influenced corrosion (MIC) in marine applications remains largely unclear, partly because of the challenge in mapping local structure–property relationships. Focusing on sulphate-reducing bacteria, the onset and rate of MIC on low-carbon marine steel samples were analysed with a wide range of grain size and as a function of the local surface crystallography using a combination of optical and electron microscopy, mass loss measurements, and electrochemical testing. It is shown that the alloy’s resistance to MIC decreases with increasing in grain size. A significant effect of the local crystallographic orientation on the material’s dissolution rate is also recorded, which is lowest along the 〈100〉 crystallographic orientation in this steel when exposed to artificial seawater. These findings outline a clear relationship between the microstructure and the susceptibility to MIC in marine steel, which may be used to design alloys with enhanced resistance to MIC in marine applications.

Iron corrosion concomitant with nitrate reduction by Iodidimonas nitroreducens sp. nov. isolated from iodide-rich brine associated with natural gas.

Microbially influenced corrosion (MIC) may contribute significantly to corrosion-related failures in injection wells and iron pipes of iodine production facilities. In this study, the iron (Fe0) corroding activity of strain Q-1 isolated from iodide-rich brine in Japan and two Iodidimonas strains phylogenetically related to strain Q-1 were investigated under various culture conditions. Under aerobic conditions, the Fe0 foil in the culture of strain Q-1 was oxidized in the presence of nitrate and yeast extract, while those of two Iodidimonas strains were not. The amount of oxidized iron in this culture was six times higher than in the aseptic control. Oxidation of Fe0 in aerobic cultures of nitrate-reducing bacterium Q-1 was dependent on the formation of nitrite from nitrate. This Fe0 corrosion by nitrate-reducing bacterium Q-1 started after initial nitrite accumulation by day 4. Nitrate reduction in strain Q-1 is a unique feature that distinguishes it from two known species of Iodidimonas. Nitrite accumulation was supported by the encoding of genes for nitrate reductase and the missing of genes for nitrite reduction to ammonia or nitrogen gas in its genome sequence. Phylogenetic position of strain Q-1 based on the 16S rRNA gene sequence was with less than 96.1% sequence similarity to two known Iodidimonas species, and digital DNA-DNA hybridization (dDDH) values of 17.2-19.3%, and average nucleotide identity (ANI) values of 73.4-73.7% distinguished strain Q-1 from two known species. In addition of nitrate reduction, the ability to hydrolyze aesculin and gelatin hydrolysis and cellular fatty acid profiles also distinguished strain Q-1 from two known species. Consequently, a new species, named Iodidimonas nitroreducens sp. nov., is proposed for the nitrate-reducing bacterium strain Q-1T.

The potency of spores and biosurfactant of Bacillus clausii as a new biobased sol-gel coatings for corrosion protection of carbon steel ST 37 in water cooling systems

The structures of water cooling systems are prone to microbially-influenced corrosion (MIC) due to the favorable conditions for microbial growth. Biofilm formation accelerates corrosion, leading to reduced system efficiency, structural damage, and significant financial losses. Encapsulating viable bacterial spores and biosurfactant within a silica-based sol-gel coating offers an eco-friendly approach to prevent this type of corrosion. Bacillus clausii, known for its antimicrobial biosurfactant production capability, was utilized in this study to investigate the impact of spores and biosurfactant addition to silica-based sol-gel coatings in inhibiting biofilm formation and preventing corrosion in water cooling systems. Microbiological analysis of the biofilm was conducted using the total plate count method, while the corrosion process was analyzed through electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The viability of B. clausii spores within the sol-gel matrix was determined to be 20.8 %. The presence of bacterial spores and biosurfactant significantly increased the hydrophobicity of the sol-gel coating. Incorporating spores within the sol-gel matrix delayed biofilm formation for up to 12 days, while biosurfactant addition showed the smallest biofilm abundance (2.23×105 CFU/mL) at its maturation phase compare to others. After 180 days of incubation, analysis of Bode and Tafel plots demonstrated that the sol-gel coating containing biosurfactant maintained excellent anti-corrosion performance, exhibiting an impedance of 104 Ω cm2, Ecorr of -0.398 V vs SCE, and icorr of 0.51 µA/cm2. SEM-EDS analysis of the surface sample revealed a comparably smooth and uniform surface with a minimal abundance of exposed Fe atoms at 0.12 %. In conclusion, this study demonstrated the high potency of the sol-gel coating supplemented with biosurfactant in inhibiting biofilm formation and corrosion on metals in water cooling systems.

Microbially Influenced Corrosion of Steel in Marine Environments: A Review from Mechanisms to Prevention.

Microbially influenced corrosion (MIC) is a formidable challenge in the marine industry, resulting from intricate interactions among various biochemical reactions and microbial species. Many preventions used to mitigate biocorrosion fail due to ignorance of the MIC mechanisms. This review provides a summary of the current research on microbial corrosion in marine environments, including corrosive microbes and biocorrosion mechanisms. We also summarized current strategies for inhibiting MIC and proposed future research directions for MIC mechanisms and prevention. This review aims to comprehensively understand marine microbial corrosion and contribute to novel strategy developments for biocorrosion control in marine environments.

Deciphering and predict corrosion effect, influencing factors and microbial mechanism of sewer concrete corrosion based on extensive data analysis and machine learning

ABSTRACT This study investigated the effect of environmental parameters on microbial-induced concrete corrosion during three corrosion stages. The corrosion effects and influencing factors in three corrosion stages were deeply analyzed and predicted, and the mechanism of microbial corrosion was summarized. When the H2S concentration was lower than about 15.0 mg/m3, the corrosion was maintained in stage II, which greatly delays the intensification of corrosion. In stage III, the H2S concentration has the significantly accelerate the corrosion rate. Additionally, incorporating min, max and mean values of input parameters greatly improved the accuracy of machine learning predictions of corrosion rates (R2 >0.99). Acidithiobacillus was found to be dominant in the microbial community at H2S concentrations of 12.0–37.5 mg/m3, and increased temperature promoted the reproduction of Acidithiobacillus.

Potential influence of microorganisms on the corrosion of carbon steel in the French high‐level long‐lived radioactive waste disposal context at 80°C

AbstractIn this study, experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high‐level radioactive waste disposal. The exposures were carried out at 80°C in different repository relevant conditions, including the presence of different cement‐grout mixtures as filling material. Biotic conditions with nutrient and nonsterile conditions with indigenous microbes added from Callovo Oxfordian clayey rock and without nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at Andra's Underground Research Laboratory and microorganisms from microbial culture collection centers. Corrosion kinetics were determined using traditional coupons and completed with real‐time corrosion sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next‐generation sequencing. The obtained results show no significant MIC and a reduced risk with the use of more alkaline filling material.

Microstructure, corrosion resistance, and antibacterial property of HVAF-sprayed Cu55Ti25Zr15Ni5 coating

The aim of this paper is to develop a protective coating with both corrosion resistance and microbially-influenced corrosion resistance. We reported a Cu55Ti25Zr15Ni5 amorphous powder, which was deposited into a coating by high velocity air-fuel spray. The coating was characterized via X-ray diffractometer, field-emission scanning electron microscope, and transmission electron microscope. For the electrochemical behavior, potentiodynamic polarization and electrochemical impedance spectroscopy were employed. Antibacterial property was assessed in terms of the inhibitory effect on Pseudomonas aeruginosa. The study findings revealed a crystallization temperature of 465 ℃ for the powder. The coating was dense with a lamellar structure, consisting of amorphous phase, Cu0.81Ni0.19 and tetragonal-ZrO2. In seawater, the coating showed a polarization resistance of 8581 Ω·cm−2, with corrosion dominated by Warburg diffusion. The coating formed a natural Cu2O-ZrO2-TiO2 film, while the corrosion products consisting of CuO, ZrO2, and TiO2. Notably, the coating displayed a bactericidal rate of (83.1 ± 4.5)% within 24 h. This work provided valuable insights into the preparation of Cu-based amorphous coating, while demonstrating its potential to resist microbially-influenced corrosion.

Review on Microbially Influenced Concrete Corrosion.

Microbially influenced concrete corrosion (MICC) causes substantial financial losses to modern societies. Concrete corrosion with various environmental factors has been studied extensively over several decades. With the enhancement of public awareness on the environmental and economic impacts of microbial corrosion, MICC draws increasingly public attention. In this review, the roles of various microbial communities on MICC and corresponding protective measures against MICC are described. Also, the current status and research methodology of MICC are discussed. Thus, this review aims at providing insight into MICC and its mechanisms as well as the development of protection possibilities.

Efficiency of didecyldimethylammonium chloride as a microbial corrosion inhibitor for 7B04 aluminum alloy in an aircraft fuel system

Efficiency of didecyldimethylammonium chloride as a microbial corrosion inhibitor for 7B04 aluminum alloy in an aircraft fuel system

Accelerated Microbial Corrosion by Magnetite and Electrically Conductive Pili through Direct Fe0 -to-Microbe Electron Transfer.

Electrobiocorrosion, the process in which microbes extract electrons from metallic iron (Fe0 ) through direct Fe0 -microbe electrical connections, is thought to contribute to the costly corrosion of iron-containing metals that impacts many industries. However, electrobiocorrosion mechanisms are poorly understood. We report here that electrically conductive pili (e-pili) and the conductive mineral magnetite play an important role in the electron transfer between Fe0 and Geobacter sulfurreducens, the first microbe in which electrobiocorrosion has been rigorously documented. Genetic modification to express poorly conductive pili substantially diminished corrosive pitting and rates of Fe0 -to-microbe electron flux. Magnetite reduced resistance to electron transfer, increasing corrosion currents and intensifying pitting. Studies with mutants suggested that the magnetite promoted electron transfer in a manner similar to the outer-surface c-type cytochrome OmcS. These findings, and the fact that magnetite is a common product of iron corrosion, suggest a potential positive feedback loop of magnetite produced during corrosion further accelerating electrobiocorrosion. The interactions of e-pili, cytochromes, and magnetite demonstrate mechanistic complexities of electrobiocorrosion, but also provide insights into detecting and possibly mitigating this economically damaging process.

Accelerated Microbial Corrosion by Magnetite and Electrically Conductive Pili through Direct Fe0‐to‐Microbe Electron Transfer

AbstractElectrobiocorrosion, the process in which microbes extract electrons from metallic iron (Fe0) through direct Fe0‐microbe electrical connections, is thought to contribute to the costly corrosion of iron‐containing metals that impacts many industries. However, electrobiocorrosion mechanisms are poorly understood. We report here that electrically conductive pili (e‐pili) and the conductive mineral magnetite play an important role in the electron transfer between Fe0 and Geobacter sulfurreducens, the first microbe in which electrobiocorrosion has been rigorously documented. Genetic modification to express poorly conductive pili substantially diminished corrosive pitting and rates of Fe0‐to‐microbe electron flux. Magnetite reduced resistance to electron transfer, increasing corrosion currents and intensifying pitting. Studies with mutants suggested that the magnetite promoted electron transfer in a manner similar to the outer‐surface c‐type cytochrome OmcS. These findings, and the fact that magnetite is a common product of iron corrosion, suggest a potential positive feedback loop of magnetite produced during corrosion further accelerating electrobiocorrosion. The interactions of e‐pili, cytochromes, and magnetite demonstrate mechanistic complexities of electrobiocorrosion, but also provide insights into detecting and possibly mitigating this economically damaging process.

Electrochemical Investigation of C-Steel Corrosion Inhibition, In Silico, and Sulfate-Reducing Bacteria Investigations Using Pyrazole Derivatives.

The inhibitory impact of the two synthesized pyrazole derivatives (3 and 4) toward metallic and microbial corrosion was investigated. Using open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy, it was possible to determine their ability to prevent the corrosion of C-steel in 1 M HCl, which was significantly enhanced with increasing concentration (ex. 93%). They act as mixed-type inhibitors, according to polarization curves. The compounds under investigation were adsorbed on a C-steel surface in 1 M HCl following the Langmuir isotherm model. The double-layer capacitance was decreased, and the charge transfer resistance (Rct) was raised due to the examined inhibitors' adsorption. Investigating changes in the surface morphology and confirming the corrosion inhibition mechanism are done using scanning electron microscopy. Density functional theory calculations and Monte Carlo simulations were also conducted to show the adsorption affinity of the understudied compounds over the steel substrate in neutral and protonated forms. Furthermore, the antimicrobial performance of the two synthesized pyrazoles against sulfate-reducing bacteria was evaluated, and the recorded inhibition efficiency was 100%. The current research shows important developments in producing highly effective anticorrosion and antimicrobial pyrazole derivatives.

The Isolation of Anaerobic and Facultative Anaerobic Sulfate-Reducing Bacteria (SRB) and a Comparison of Related Enzymes in Their Sulfate Reduction Pathways.

Sulfate-reducing bacteria (SRB) are an important group of microorganisms that cause microbial corrosion. In this study, culturable SRB were isolated and identified from the inner rust layer of three kinds of steel and from sediments, and a comparison of amino acid sequences encoding related enzymes in the sulfate reduction pathway between anaerobic and facultative anaerobic SRB strains was carried out. The main results are as follows. (1) Seventy-seven strains were isolated, belonging to five genera and seven species, with the majority being Desulfovibrio marinisediminis. For the first time, Holodesulfovibrio spirochaetisodalis and Acinetobacter bereziniae were separated from the inner rust layer of metal, and sulfate reduction by A. bereziniae, Virgibacillus dokdonensis, and Virgibacillus chiguensis, etc., was also demonstrated for the first time. (2) Three strains of strictly anaerobic bacteria and four strains of facultative anaerobic bacteria were screened from seven bacterial strains. (3) Most of the anaerobic SRB only contained enzymes for the dissimilatory sulfate reduction pathway, while those of facultative anaerobic bacteria capable of producing hydrogen sulfide included two possible ways: containing the related enzymes from the dissimilatory pathway only, or containing enzymes from both dissimilatory and assimilation pathways. This study newly discovered that some bacterial genera exhibit sulfate reduction ability and found that there are differences in the distribution of enzymes related to the sulfate reduction pathway between anaerobic and facultative anaerobic SRB type trains, providing a basis for the development and utilization of sulfate-reducing bacterial resources and furthering our understanding of the metabolic mechanisms of SRB.