Search Results (28)

Microorganisms take an active part in the processes of microbiologically influenced corrosion, which is protected against by using bactericides—often toxic compounds—with inhibitory properties. There are many studies of eco-friendly “green” biocides/inhibitors, in particular those based on microbial metabolites. Indicators for the processes of microbial corrosion of steel 3 induced by the sulfate-reducing bacteria Desulfovibrio oryzae NUChC SRB2 under the influence of the strains Bacillus velezensis NUChC C2b and Streptomyces gardneri ChNPU F3 have not been investigated, which was the aim of this study. The agar well diffusion method (to determine the antibacterial properties of the supernatants) was used, along with the crystal violet (to determine the biomass of the biofilm on the steel) and gravimetric methods (to determine the corrosion rate). A moderate adhesiveness to steel 3 was established for D. oryzae due to its biofilm-forming ability. The presence of a supernatant on cultures of S. gardneri, B. velezensis and their mixture (2:1) did not reduce the biofilm-forming properties of D. oryzae. Compared to the control, a decrease in the corrosion rate was recorded for the variant of the mixture of the studied bacterial culture supernatants. This indicates the potential of this mixture for use in corrosion protection in environments with sulfate-reducing bacteria, which requires further research. Full article

Desulfovibrio vulgaris is an anaerobic microorganism belonging to the group of sulphate-reducing bacteria (SRB). SRB form biofilms on metal surfaces in water supply networks, producing a microbiologically influenced corrosion (MIC). This process produces the deterioration of metal surfaces, leading to high economic costs and different environmental safety and health problems related to its chemical treatment. For that reason, rapid and accurate detection methods of SRB are needed. In this work, a new detection system for Desulfovibrio has been developed using gated nanoporous materials. The probe is based on hybrid nanoporous alumina films encapsulating a fluorescent molecule (rhodamine B), whose release is controlled by an oligonucleotide gate. Upon exposure to Desulfovibrio’s genomic material, a movement of the oligonucleotide gatekeeper happens, resulting in the selective delivery of the entrapped rhodamine B. The developed material shows high selectivity and sensitivity for detecting Desulfovibrio DNA in aqueous buffer and biological media. The implementation of this technology for the detection of Desulfovibrio as a tool for monitoring water supply networks is innovative and allows real-time in situ monitoring, making it possible to detect the growth of Desulfovibrio inside of pipes at an early stage and perform timely interventions to reverse it. Full article

Zirconia crowns are employed in pediatric dentistry for the complete restoration of anterior and posterior deciduous teeth. They are considered the best option due to their esthetic appeal, high strength, biocompatibility, and resistance to wear and corrosion. This study aims to evaluate the physico-chemical, cytological, and microbial properties of zirconia crowns to determine their biocompatibility, safety for surrounding tissues, and effectiveness in preventing microbial influence on tooth tissue based on their biofilm deposition potential. XRD measurements were conducted to confirm the crown composition. For the microbiological examination, a quantitative assessment of the adhesion capacity of the analyzed strains and the formation of a mixed biofilm was performed using a Zeiss Cell Observer SD confocal microscope. This study used a mixed biofilm containing Streptococcus mutans (ATCC 25175), Lactobacillus rhamnosus (ATCC 9595), Candida albicans (ATCC 90028), and Candida albicans (ATCC 10231) to simulate the oral environment and the possible dynamics created between different types of microorganisms. A direct contact method was used to assess cytotoxic properties. The zirconia crown biomaterial shows a low ability to adhere to specific microorganisms, with L. rhamnosus predominating, indicating low clinical potential for causing inflammation of the tissues surrounding the crown. The cytotoxic properties of the biomaterial were found to be at level 2, indicating moderate cytotoxicity. Their biggest flaws are price and the need for passive fitting, which involves aggressive grinding; this is a potential limitation when it occurs in children, as their cooperation with the treatment can be difficult to guarantee. Full article

Microbiologically influenced corrosion (MIC) is one of the key causes of material failure in marine engineering, and sulfate-reducing bacteria (SRB) and iron-oxidizing bacteria (IOB) are typical representatives of anaerobic and aerobic microorganisms, respectively. These microorganisms are widely present in marine environments and can form synergistic communities on the surface of metal materials, posing a corrosion threat to them. At the same time, the presence of mixed bacteria may have an effect on cathodic protection, so this study investigates the growth metabolism of mixed SRB and IOB under different cathodic protection potentials in an impressed current cathodic protection (ICCP) system in a marine environment containing SRB and IOB. It also examines the attachment of these microorganisms to the anode and cathode, and the impact on cathodic protection efficiency. The results indicate that in a marine environment containing IOB and SRB, the cathodic protection efficiency of the ICCP system increases with the negative shift of the protection potential. A more positive cathodic protection potential promotes the adhesion of mixed bacteria on the electrode surface and the formation of a biofilm, which reduces cathodic protection efficiency. In contrast, at a cathodic protection potential of −1.05 V (SCE), bacterial growth is inhibited, and a dense crystalline corrosion film primarily composed of Fe₂O₃ and Fe(OH)₃ forms on the cathode surface. This film effectively protects the cathodic metal, significantly mitigating MIC. Full article

This study explores the corrosion behavior of pure copper in simulated oilfield-produced water and evaluates the inhibitory effect of cetylpyridinium chloride (CPC) on microbiologically influenced corrosion (MIC). Weight loss tests, potentiodynamic polarization, and pitting analyses revealed that sulfate-reducing bacteria (SRB) activity significantly accelerated corrosion, with the maximum pit depth reaching 7.54 µm in the absence of CPC—approximately 1.83 times greater than under abiotic conditions. The introduction of CPC substantially reduced corrosion rates and pit depths, with maximum pit depths decreasing to 2.97 µm, 1.11 µm, and 1.02 µm at 10, 50, and 80 mg/L CPC, respectively. CPC inhibited SRB biofilm formation, metabolic activity, and corrosion product accumulation, achieving an inhibition efficiency of up to 89% at 80 mg/L. These findings highlight CPC’s dual role as a biocide and a corrosion inhibitor, offering a promising approach to controlling MIC in oilfields and similar industrial environments. Full article

Microorganisms cause microbiologically influenced corrosion, for the prevention of which bactericide inhibitors are used. The aim of the work was to study in vitro the sensitivity of SRB Desulfovibrio oryzae NUChC SRB1 to different concentrations of dimethyl sulfoxide (DMSO), and evaluate the indicators of the microbial corrosion of steel induced by this bacterium in the presence of the pharmaceutical drugs DMSO and paracetamol. The sensitivity of SRB D. oryzae to 1–100% DMSO (v/v) was studied via the dilution method in Postgate’s “C” liquid medium. The corrosion activity of D. oryzae against steel 3 was investigated under DMSO and paracetamol treatment at a final concentration of 45% (v/v) and 0.2% (w/v), respectively, according to the ability of bacteria to form a biofilm on the surface of the steel samples (via the crystal violet method) and the effect on the corrosion rate (via the gravimetric method). It was revealed that DMSO affected D. oryzae NUChC SRB1 and exhibited bactericidal properties (at a concentration range of 10–100%, v/v) and antibiofilm properties (at a concentration of 45%, v/v). Despite its antibiofilm properties confirmed by the reduction in bacterial biofilm mass, anticorrosion features were not observed in the model 35-day conditions of the microbial corrosion of steel in an anaerobic environment with bacterial sulfate reduction. Paracetamol (0.2%, w/v) did not affect biofilm formation by SRB under these conditions, and significantly contributed to an increase in the rate of the microbial corrosion of steel. The prospect of further research is to assess the effect of DMSO and paracetamol on the indicators of microbial corrosion induced by SRB under the influence of the concentrations of these compounds found in wastewater, to clarify the possible additional causes of damage to the equipment of treatment plants. Further research should also be directed at investigating the antimicrobial properties of complexes of compounds with DMSO, which should be considered as an ecological solution to the problem of microbiologically influenced corrosion prevention. Full article

Microbial corrosion is the deterioration of materials associated with microorganisms in environments, especially in oil- and gas-dominated sectors. It has been widely reported to cause great losses to industrial facilities such as drainage systems, sewage structures, food-processing equipment, and oil and gas facilities. Generally, bacteria, viruses, and other microorganisms are the most important microorganisms associated with microbial corrosion. The destructive nature of these microorganisms differs based on the kind of bacteria involved in the corrosion mechanism. Amongst the microorganisms related to microbial corrosion, sulfate-reducing bacteria (SRB) is reported to be the most common harmful bacteria. The detailed mechanistic explanations relating to the corrosion of pipelines by sulfate-reducing bacteria are discussed. The mechanism of microbial corrosion in pipelines showing the formation of pitting corrosion and cathodic depolarization is also reported. The current review provides theoretical information for the control and protection of pipelines caused by microbial corrosion and how new eco-friendly protection methods could be explored. Full article

Designing minimally invasive, defect-free coatings based on conformal graphene layers to shield metals from both abiotic and biotic forms of corrosion is a persistent challenge. Single-layer graphene (SLG) grown on polycrystalline copper (PC-Cu) surfaces often have inherent defects, particularly at Cu grain boundaries, which weaken their barrier properties and worsen corrosion through grain-dependent mechanisms. Here, we report that an SLG grown via chemical vapor deposition (CVD) on Cu (111) single crystal serves as a high-performance coating to lower corrosion by nearly 4–6 times (lower than bare Cu (111)) in abiotic (sulfuric acid) and microbiologically influenced corrosion (MIC) environments. For example, the charge transfer resistance for SLG/Cu (111) (3.95 kΩ cm²) was 2.5-fold higher than for bare Cu (111) (1.71 kΩ cm²). Tafel analysis corroborated a reduced corrosion current (42 ± 3 µA cm⁻²) for SLG/Cu (111) compared to bare Cu (111) (115 ± 7 µA cm⁻²). These findings are consistent with the results based on biofilm measurements. The SLG/Cu (111) reduced biofilm formation by 3-fold compared to bare Cu (111), increasing corrosion resistance, and effectively mitigating pitting corrosion. The average depths of the pits (3.4 ± 0.6 µm) for SLG/Cu (111) were notably shallower than those of bare Cu (111) (6.5 ± 1.2 µm). Surface analysis of the corrosion products corroborated these findings, with copper sulfide identified as a major component across both surfaces. The absence of grain boundaries in Cu (111) resulted in high-quality SLG manifesting higher barrier properties compared to SLG on PC-Cu. Our findings show promise for using the presented strategy for developing durable graphene coatings against diverse forms of corrosion. Full article

The chemical, electrochemical and microbiological corrosive degradation of metals is a versatile harmful problem that causes significant economic loss all over the world. The mitigation of these undesired processes needs basic knowledge on the mechanisms of processes in order to control these reactions with environmentally acceptable chemicals and techniques. This paper focuses on the up-to-date possibilities that help in the mitigation of chemical/electrochemical corrosion and, at the same time, in decrease the deposition of corrosion relevant microorganisms, as the microbes in biofilms are more dangerous than the planktonic cells. Some chemicals or coatings due to their specific properties can fulfill multiple functions; they are able to control the corrosion caused by aggressive materials (that could be the metabolites of a corrosion relevant microorganism) and, at the same time, reduce the microbial adhesion. These additives that have important application possibilities in the chemical industry, marine environment, medical field, nanoelectronics, etc., can save energy, materials consumption and cost, and, at the same time, the efficiency is improved. All resolutions will be brought into prominence when the same chemicals (either in dissolved form or in coatings/nanolayers) can effectively control the different appearance of corrosion and, additionally, the microbial adhesion and microbiologically influenced corrosion. Full article

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. Full article

MIC (microbiologically influenced corrosion) is problematic in many industries, especially in the oil and gas industry. In this work, N80 carbon steel for pipelines was tested with 26Cr3Mo chromium pipeline steel for comparison in SRB (sulfate-reducing bacterium) MIC mitigation using a THPS (tetrakis hydroxymethyl phosphonium sulfate)-based commercial biocide (Biotreat 5475 with 75–80% THPS by mass). Peptide A, a nature-mimicking synthetic cyclic peptide (cys-ser-val-pro-tyr-asp-tyr-asn-trp-tyr-ser-asn-trp-cys) with biofilm dispersal ability was used as a biocide enhancer. Metal coupons covered with 3-d old Desulfovibrio ferrophilus IS5 biofilms were immersed in different biocide solutions. After 1-h treatment, 200 ppm Biotreat 5475, 200 ppm Biotreat 5475 + 200 nM (360 ppb) Peptide A, and 400 ppm Biotreat 5475 achieved 0.5-log, 1.7-log and 1.9-log reductions in sessile cell count on N80, and 0.7-log, 1.7-log, and 1.8-log on 26Cr3Mo, respectively. The addition of 200 nM Peptide A cut the THPS biocide dosage by nearly half. Biocide injection tests in electrochemical glass cells after 1 h exhibited 15%, 70%, and 72% corrosion inhibition efficiency (based on corrosion current density) on N80, and 27%, 79%, 75% on 26Cr3Mo, respectively. Linear polarization resistance and electrochemical impedance spectrometry results also indicated antimicrobial efficacies. Full article

The corrosion of carbon steel causes dramatic economic losses each year. Since conventional corrosion prevention approaches may cause pollution problems to the environment, ecofriendly and effective corrosion approaches are desired. Microbiologically influenced corrosion inhibition (MICI) has been reported as a sustainable corrosion prevention method. This work aims to evaluate the corrosion inhibition effect of two bacterial strains, Tenacibaculum mesophilum D-6 and Bacillus sp. Y-6 by choosing Q235 carbon steel as a model system. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and a series of electrochemical techniques were applied to study the corrosion prevention effect. The electrochemical and pitting results indicated that T. mesophilum D-6 displayed a better corrosion protection effect. T. mesophilum D-6 formed a denser and thicker biofilm on the Q235 surface than Bacillus sp. Y-6. The maximum thickness of the T. mesophilum D-6 biofilms was 11.6 ± 0.7 μm, which is about twice as thick than that of Bacillus sp. Y-6. The corrosion prevention mechanism was ascribed to the formation of biofilms as a barrier to block corrosive agents such as O₂. This study provides a theoretical foundation for the application of biofilms as green and effective corrosion inhibitors for carbon steel. Full article

The bactericide benzalkonium bromide is widely used to kill Pseudomonas aeruginosa, which causes microbiologically influenced corrosion (MIC). However, the extensive use of benzalkonium bromide will enhance bacterial drug resistance and cause environmental pollution. In this study, benzalkonium bromide combined with Cu-bearing 2205 duplex stainless steel (2205-Cu DSS) was used to kill Pseudomonas aeruginosa; the germicidal rate of the combination of benzalkonium bromide and 2205-Cu DSS was 24.2% higher than that of using benzalkonium bromide alone, after five days. The antibacterial efficacy was evaluated using an antibacterial test and biofilm observation. The results showed that, in the presence of P. aeruginosa, the combination of 23.44 ppm benzalkonium bromide and 2205-Cu DSS showed the best antibacterial efficacy. Full article

Sulfate-reducing bacteria (SRB) have long been reported to participate in metal corrosion processes in anoxic environments. However, existing theories still need enrichment by identifying more corrosive microorganisms and exploring more plausible microbiologically-influenced corrosion pathways. In this study, a strain SRB-Z was isolated from the Pearl River in Guangzhou, and its effect and mechanisms on corrosion of Q235 carbon steel were examined. The biofilms, corrosion products, pits, and corrosion electrochemistry were characterized by SEM, XPS, CLSM, EDS, white light interferometer 3D profilometry, and electrochemical analysis, respectively. The results of this study indicate that SRB-Z could cause serious pitting of Q235 carbon steel. The maximum pit depth reached 54 μm after immersion corrosion for 7 days. Strain SRB-Z promoted the cathodic reaction rate of Q235. The relative analyses revealed that pitting corrosion occurred because of galvanic corrosion caused by the formation of an FeS-SRB/Fe galvanic couple under the synergistic effect of the SRB-Z biofilm and its metabolite (H₂S) on the Q235 coupon surfaces. Full article

Microbiologically influenced corrosion (MIC) of metal alloys is promoted by biofilms formed on metal surfaces. In the marine environment, MIC causes serious metal infrastructure problems, which lead to significant economic losses. In this study, we used an enrichment culture approach to examine the bacterial community that grows on metal surface at levels below the detection limit as a preliminary study for developing guidelines to prevent biofilm formation. An enrichment culture approach was employed to analyze the bacterial community on metal surface without biofilms and corrosion. Genomic DNA was extracted from culture sample after incubation in the enrichment culture with a metal piece, and then the V3–V4 variable regions of the bacterial 16S rRNA gene were amplified using the extracted genomic DNA as the template. Subsequently, using a next-generation sequencing approach, the amplified V3–V4 regions were sequenced, and the bacterial community was analyzed using the QIIME 2 microbiome bioinformatics platform. Using this enrichment culture approach, more than 80 bacterial genera were detected with Sphingomonas bacteria exhibiting the highest relative abundance (44%). These results demonstrated that this method could be useful for bacterial community analysis for bacteria below detection limits, and will serve as a basis for the development of the guidelines. Full article