Ship body steel structure composite electrogenesis bacterium biological membrane anticorrosive coating as well as preparation method and application thereof

Abstract

The invention relates to a ship body steel structure composite electrogenesis bacterium biological membrane anticorrosive coating and a preparation method and application thereof, and belongs to the technical field of marine ship steel structure anticorrosive coating preparation. According to the specific scheme, the ship body steel structure composite electrogenesis bacterium biological membrane anticorrosive coating comprises a coating I and a coating II, the outer surface of a ship body steel structure is coated with the coating I, and the outer surface of the ship body steel structure is coated with the coating II; the surface of the coating I is coated with the coating II, the coating I comprises diatom ooze I and seawater salt-tolerant anaerobic electricity-producing bacteria, and the seawater salt-tolerant anaerobic electricity-producing bacteria grow in pores of the diatom ooze I; the coating II comprises diatom ooze II and seawater salt-tolerant facultative anaerobic saccharomycetes, and the seawater salt-tolerant facultative anaerobic saccharomycetes grow in internal pores of the diatom ooze II. Corrosion prevention of the ship body steel structure is achieved through the environment-friendly microbial electrochemical technology, traditional epoxy resin and polyurethane anti-corrosion paint are replaced, and the technology belongs to the environment-friendly anti-corrosion technology.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating preparation technology for marine ship steel structures, specifically relating to an anti-corrosion coating for ship hull steel structures composed of composite electrogenic bacteria biofilm, its preparation method, and its application. Background Technology

[0002] The seawater has high salinity (generally around 3.5%, corresponding to a chloride concentration of 1.9%) and is oxygen-rich (oxygen dissolved at a concentration of 5.35 cm³). 3 The presence of marine organisms (plankton and plants) creates conditions conducive to electrochemical corrosion, microbial adhesion corrosion, and oxygen corrosion of ship hull steel structures, causing corrosive damage, especially to the hull structure. Corrosion has become the most important factor affecting ship safety, lifespan, and reliability, and is receiving considerable attention. Corrosion and fouling protection costs account for nearly one-third of the total ship maintenance cost, making it a critical aspect of ship construction, operation, and maintenance. Well-known traditional anti-corrosion technologies include coatings with fluorocarbon resins, chlorinated rubber, epoxy resins, and vinyl resins. Commonly used agents to prevent bioadhesion include organotin compounds, mercuric oxide, DDT, organolead compounds, and copper powder. These traditional anti-corrosion technologies suffer from significant environmental pollution, poor long-term effectiveness, toxicity, and high carbon emissions. Summary of the Invention

[0003] Addressing the well-known serious problems of electrochemical corrosion caused by high seawater salinity, biological corrosion caused by marine organism adhesion, and oxygen corrosion in marine vessels; as well as the significant environmental pollution and poor long-term effectiveness of existing traditional anti-corrosion technologies, this invention provides a composite electrogenic bacterial biofilm anti-corrosion coating for ship hull steel structures, its preparation method, and its application, offering green and low-carbon technological advantages. Technological innovation in ship anti-corrosion materials is of great significance for ensuring ship safety, reducing major catastrophic accidents, and extending the service life of ships.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A composite electrogenic biofilm anticorrosive coating for ship hull steel structures includes coating I and coating II. Coating I is applied to the outer surface of the ship hull steel structure, and coating II is applied to the surface of coating I. Coating I includes diatomaceous earth I and seawater salt-tolerant anaerobic electrogenic bacteria, with the seawater salt-tolerant anaerobic electrogenic bacteria growing inside the pores of diatomaceous earth I. Coating II includes diatomaceous earth II and seawater salt-tolerant facultative anaerobic yeast, with the seawater salt-tolerant facultative anaerobic yeast growing inside the pores of diatomaceous earth II.

[0006] Furthermore, the salt-tolerant anaerobic electrogenic bacteria is Shewanella oneidensis MR-1, and the salt-tolerant facultative anaerobic yeast includes one or a combination of Cryptococcus and Isaac's yeast.

[0007] Furthermore, the thickness of coating I is 1-3 mm, and the thickness of coating II is 1-3 mm.

[0008] A method for preparing the aforementioned anti-corrosion coating includes the following steps:

[0009] Step 1: Apply coating I to the outer surface of the ship's steel structure. Coating I includes diatomaceous earth I and salt-tolerant anaerobic electrogenic bacteria, which grow inside the pores of diatomaceous earth I.

[0010] Step 2: Apply coating 2 to the surface of coating 1. Coating 2 includes diatomaceous earth II and facultative anaerobic microorganisms. The salt-tolerant facultative anaerobic yeast grows in the internal pores of diatomaceous earth II.

[0011] The application of a composite electrogenic biofilm anti-corrosion coating for ship hull steel structures utilizes a diatomaceous earth coating as a base. A composite microbial community grows within the pores of this coating, irreversibly adhering to the outer surface of the ship hull through the diatomaceous earth base. This composite microbial community comprises an inner layer of domesticated and isolated salt-tolerant anaerobic electrogenic bacteria (Shewanella) and their extracellular polymers, and an outer layer of salt-tolerant facultative anaerobic yeasts (Cryptococcus and / or Isaac's yeast) and their extracellular polymers. On one hand, the outer layer of salt-tolerant facultative anaerobic yeasts consumes dissolved oxygen in the water, metabolizing large marine organic molecules to form small organic molecules such as methanol and acetic acid. On the other hand, the inner layer of salt-tolerant anaerobic electrogenic bacteria—Shewanella—utilizes the metabolism of these small organic molecules to generate charge, which is then transferred to the steel hull structure, acting as a cathode to inhibit electrochemical corrosion of the hull steel structure in high-salinity seawater. Simultaneously, the charge generated by the salt-tolerant anaerobic electrogenic bacteria Shewanella is transferred to attached shellfish, causing the shellfish to secrete lectins containing lectins containing Ca2+ metal ions. 2+ Or Mg 2+ The lectins are reduced, forming Ca and Mg deposits, which deactivate the lectins and effectively inhibit the adhesion and growth of marine shellfish, ensuring the bioadhesion safety of the ship's hull.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The use of environmentally friendly microbial electrochemical technology to achieve corrosion protection of ship hull steel structures replaces traditional epoxy resin and polyurethane anti-corrosion coatings, and is a green anti-corrosion technology.

[0014] The diatomaceous earth in the coating provides a nano-space structure. It utilizes seawater salt-tolerant facultative anaerobic yeast in combination with seawater salt-tolerant anaerobic electrogenic bacteria to generate charges by metabolizing organic matter. The steel structure is used as a cathode to transfer the charges to the ship's steel structure, thereby achieving electrochemical protection of the steel structure.

[0015] The diatomaceous earth in the coating provides an ordered microporous spatial structure, utilizing the combined metabolism of seawater salt-tolerant facultative anaerobic yeast and seawater salt-tolerant anaerobic electrogenic bacteria to regulate dissolved oxygen and pH in the environment, thereby inhibiting the chemical corrosion of the steel structure.

[0016] Using the charge generated by salt-tolerant anaerobic electrogenic bacteria in seawater to reduce the lectin Ca in the mucus secreted by marine mollusks 2+ Mg 2+ Ions deactivate the bioadhesive, thereby eliminating its adhesive properties and improving the ship's resistance to bioadhesion, thus protecting the ship's steel structure. Attached Figure Description

[0017] Figure 1 Schematic diagram of the device for testing and acclimatization of Shewanella, a salt-tolerant anaerobic electrogenic bacterium in seawater;

[0018] Figure 2 Diagram showing the arrangement of the coating of microorganisms on the ship's facade: inner layer of seawater salt-tolerant anaerobic electrogenic bacteria and outer layer of seawater salt-tolerant facultative anaerobic yeast.

[0019] In the diagram, 1 represents the ship's steel structure, 2 represents coating I, and 3 represents coating II. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Example 1:

[0022] A composite electrogenic biofilm anticorrosive coating for ship hull steel structures includes coating I and coating II. Coating I is applied to the outer surface of the ship hull steel structure, and coating II is applied to the surface of coating I. Coating I comprises diatomaceous earth I and seawater salt-tolerant anaerobic electrogenic bacteria, the latter growing inside the pores of diatomaceous earth I. Coating II comprises diatomaceous earth II and seawater salt-tolerant facultative anaerobic yeast, the latter growing inside the pores of diatomaceous earth II. Coating I forms a tight seal around the ship hull steel structure, and coating II covers the outer surface of coating I, such as... Figure 2 As shown.

[0023] Furthermore, the salt-tolerant anaerobic electrogenic bacteria in seawater is Shewanella, and the salt-tolerant facultative anaerobic yeast in seawater includes one or a combination of Cryptococcus and Isaac's yeast.

[0024] Furthermore, the thickness of coating portion I is 1-3 mm, and the thickness of coating portion II is 1-3 mm.

[0025] Example 2:

[0026] A method for preparing a composite electrogenic bacterial biofilm anticorrosive coating for ship hull steel structures includes the following steps:

[0027] Step 1: Apply coating I (internal coating) to the outer surface of the ship's steel structure. Coating I includes diatomaceous earth I and seawater salt-tolerant anaerobic electrogenic bacteria (Shewanella). The seawater salt-tolerant anaerobic electrogenic bacteria grow inside the pores of diatomaceous earth I.

[0028] Step 2: Apply coating 2 (external coating) to the outer surface of coating 1. Coating 2 includes diatomaceous earth II and seawater salt-tolerant facultative anaerobic yeast (Cryptococcus and Isaac yeast), which grow in the internal pores of diatomaceous earth II.

[0029] The specific plan includes the following steps: 1. Isolation, purification, and electrogenicity testing of salt-tolerant anaerobic electrogenic bacteria in seawater; 2. Isolation and purification of salt-tolerant facultative anaerobic yeast in seawater; 3. Coating the inner layer of the ship's hull with diatomaceous earth containing salt-tolerant anaerobic electrogenic bacteria and coating the outer layer of the ship with diatomaceous earth containing salt-tolerant facultative anaerobic yeast, thereby forming a biofilm coating. The principle and implementation plan of the composite electrogenic biofilm corrosion protection technology for ship hull steel structures: Utilizing structured microorganisms diatoms + salt-tolerant anaerobic electrogenic bacteria *Shewanella* + salt-tolerant facultative anaerobic yeast, this composite ecosystem forms a tight wrap around the outer surface of the ship's hull. The diatomaceous earth coating utilizes the rich nanoporous structure of diatoms to provide growth space for the salt-tolerant anaerobic electrogenic bacteria and salt-tolerant facultative anaerobic yeast. This structure consists of two layers: an inner coating of diatomaceous earth + salt-tolerant anaerobic electrogenic bacteria, and an outer coating of diatomaceous earth + salt-tolerant facultative anaerobic yeast; the outer coating contains salt-tolerant facultative anaerobic yeasts (*Cryptococcus* and *Issarum*). The consumption of dissolved oxygen and the metabolism of large marine organic molecules to form small-molecule acids and alcohols maintain an anaerobic environment for the salt-tolerant anaerobic electrogenic bacteria in the inner layer of seawater, while also providing small-molecule organic carbon. The salt-tolerant anaerobic electrogenic bacteria (Shewanella) in the inner coating metabolize small-molecule organic carbon, generating an electric charge, which is then transferred to the ship's steel structure via pili, achieving cathodic protection and providing electrochemical corrosion prevention. Simultaneously, the metabolism of small-molecule acids by these bacteria regulates the pH of the microenvironment, preventing corrosion of the steel structure by biological acids. Furthermore, the electric charge generated by the salt-tolerant anaerobic electrogenic bacteria Shewanella is transferred to the calcium in the lectins of the shellfish adhering to the outer layer. 2+ Mg 2+The formation of Ca and Mg deposits deactivates the lectins, causing them to lose their adhesiveness and effectively inhibiting shellfish adhesion, thus providing protection for the steel structure.

[0030] The lectins mentioned are important immune factors in invertebrates, widely present in the extracellular matrix of shellfish, such as protein glands, hemolymph, body surface mucus, and muscles. They are also found on the surface of hemolymphocytes, in the cytoplasm, and even in the nucleus, forming the first line of defense in the body's immune system. They are also an important means for shellfish and other marine organisms to adhere to marine ship structures. Most lectins are class C lectins, and lectin molecules contain one or more metal ions necessary to maintain their activity, exhibiting metal ion dependence. Some metal ions related to lectin activity are often Ca2+. 2+ and Mg 2+ This is essential for the binding or aggregation of many sugars, and the presence of Ca is an indispensable condition for the aggregation of most lectins (such as C-type lectins). 2+ .

[0031] Diatomaceous earth, as described, is a non-metallic mineral formed from the remains of diatoms (mineral composition: opal and its varieties) found in oceans or lakes, widely distributed in temperate and tropical seas. Diatomite is one of the most widely distributed and abundant non-metallic minerals globally, with my country ranking second in the world in terms of diatomite resources. Diatomaceous earth is characterized by its loose and porous structure, strong adsorption capacity, high porosity, and low density (1.9~2.3 g / cm³). 3 Diatomaceous earth is characterized by its soft texture (Mohs hardness 1-1.5). It has high water absorption, capable of absorbing more than twice its own volume of water, providing an excellent aquatic environment for the microorganisms that grow within it. Simultaneously, diatoms possess a nanoscale porous structure (micropore diameter approximately 0.1-0.2 micrometers), with a porosity as high as 90%. These micropores are arranged regularly and neatly in circular or needle-like shapes, and the number of micropores per unit area is thousands of times greater than that of charcoal. This abundant porosity provides space for the growth of microorganisms and bacteria. Diatoms also exhibit high chemical stability; except for hydrofluoric acid, they are insoluble in any strong acid or salt solution, providing favorable conditions for diatomaceous earth to be used as an anti-corrosion coating.

[0032] 1. Screening and electrogenic performance testing of salt-tolerant anaerobic electrogenic bacteria (Shewanella oneidensis MR-1) in seawater

[0033] Shewanella (Shewanella oneidensis MR-1) belongs to the phylum Proteobacteria and is a Gram-negative microorganism. Shewanella possesses iron-reducing properties and obtains its energy for survival through fermentation under anaerobic conditions. Shewanella is widely distributed at redox interfaces in various natural environments, and its electron transfer mechanisms encompass all known electron transfer mechanisms. As a model organism for electroproduction, Shewanella is broadly representative.

[0034] The bacterial strain used in this invention was isolated from nearshore sediment samples from the Qingdao sea area. The sediment sample was placed in a nitrogen-filled Erlenmeyer flask, several glass beads were added, and the mixture was shaken for 2 hours to break up the bacterial flocs in the sludge. The sample was then serially diluted with sterile water. Single colonies were picked using sterile capillaries and transferred to anaerobic culture tubes containing solid culture medium. The enrichment medium formula (per liter of sterile water) was as follows: peptone (8.0 g / L), yeast extract (1.0 g / L), sodium acetate (16.0 g / L), sodium chloride (5.0 g / L), calcium chloride (0.1 g / L), magnesium chloride (0.1 g / L), potassium dihydrogen phosphate (1.2 g / L), cysteine ​​(1.0 g / L), and ferric citrate (4.8 g / L) added to 2% agar. The initial pH of the culture medium was adjusted to 7.0 ± 0.2, and the medium was autoclaved for 20 minutes. 1 mL of seawater sediment was inoculated into an appropriate amount of enrichment medium and cultured at 35°C for 4 weeks until the medium color changed from brown to black. After enrichment culture, the purified bacterial strain was isolated using the plate method. The above operation was repeated several times until the colonies in the tube and the cell morphology under the microscope were consistent, indicating that it was a pure strain. Further confirmation was made using electron microscopy.

[0035] After amplification, the strain was transferred to a laboratory microbial fuel cell (MFC). The anode of the battery was a graphite carbon felt inoculated with this strain in a suspension shaking incubator, and the cathode was a graphite carbon felt with attached Chlorella. The MFC adopted an upflow membrane-free structure design, with the anode at the bottom and the cathode at the top. The experimental test water was sterile water containing sodium acetate (300 mg / L), sodium chloride (5.0 g / L), calcium chloride (0.1 g / L), magnesium chloride (0.1 g / L), potassium dihydrogen phosphate (32 mg / L), and urea (100 mg / L). The influent flow rate was 2.32 mL / min, and the system operated continuously for two months. The electrochemical performance of the strain was tested. The tests showed that after stable operation, the output voltage of the device was 750 mV and the current was 190 mA, proving that the strain has electrochemical activity. A schematic diagram of the electrochemical performance testing and acclimatization device for the salt-tolerant anaerobic electrogenic bacterium *Shewanella* is shown below. Figure 1 As shown.

[0036] Table 1 MFC Experimental Parameters

[0037]

[0038] Electrode reactions within the device:

[0039] Anode reaction: (Electrogenic bacteria MR-1) (1)

[0040] Cathode reaction: (Chlorella provides dissolved oxygen through photosynthesis) (2)

[0041] Using this strain mixed with diatomaceous earth, and with an aqueous solution of sodium acetate (300 mg / L), sodium chloride (5.0 g / L), calcium chloride (0.1 g / L), magnesium chloride (0.1 g / L), potassium dihydrogen phosphate (32 mg / L), and urea (100 mg / L) as a solvent, a 1 mm thick coating was applied to 923 steel sheets (ship hull steel). After the coating stabilized, it was immersed in a 3.5 wt% NaCl solution for 40 days, and the low-frequency impedance was still as high as 3.9 × 10⁻⁶. 10 Ω cm 2 It has excellent corrosion resistance, and tests show that coating with this strain can improve the corrosion resistance of steel structures.

[0042] 2. Screening of salt-tolerant facultative anaerobic yeasts for seawater

[0043] Salt-tolerant facultative anaerobic yeasts refer to yeasts isolated from marine environments that possess high salt tolerance. These yeasts are widely distributed in seawater, seabed sediments, estuaries, and mangroves, and are also widely found in marine flora and fauna, remaining dominant organisms in the marine biosphere. Currently discovered salt-tolerant facultative anaerobic yeasts mainly include the following genera: *Debaryomyces*, *Arowia*, *Candida*, *Cryptococcus*, *Pichia*, *Rhodotorula*, *hodosporidium*, *Metschnikowia*, *Sporobolomyces*, *Kluyveromyces*, and *Lsachenkia*. This invention isolated *Cryptococcus* and *Lsachenkia* from seawater sediment near Qingdao.

[0044] Seawater salt-tolerant facultative anaerobic yeast culture medium: (1) Enrichment medium: 20g glucose, 20g peptone, 10g yeast extract, 100mg penicillin (to eliminate bacterial interference during screening), 1000mL distilled water. (2) Separation medium (PDA medium): 20g glucose, 200g potato, 12g agar, 1000mL distilled water. Take 1g of marine sediment into 50mL of enrichment medium and culture at 25℃ with shaking for 2 days. Gradually dilute the enrichment solution to 10 -3 10 -4 and 10 -5 Take 0.1 mL of the diluted solution into the isolation medium, spread it on a plate, incubate at 25℃, and observe the colony growth. For colonies containing yeast, perform streak purification.

[0045] 3. Preparation and Testing of Composite Bio-coatings

[0046] On the outer layer of a 923 steel sheet (ship hull steel) coated with a 1mm layer of diatomaceous earth and a 1mm layer of salt-tolerant anaerobic electrogenic bacteria (Shewanella oneidensis MR-1), a 1mm thick layer of diatomaceous earth and a 1mm thick layer of salt-tolerant facultative anaerobic yeast (Cryptococcus, Isaac's yeast) was applied. After the coating stabilized, the sample was immersed in a solution containing 3.5wt% NaCl and 100mg / L glucose for 10 days. The low-frequency impedance of the sample reached 6.9×10⁻⁶. 10 Ω cm 2 The combined bacterial strain coating outperforms single Shewanella coatings, and the combined bacterial strain coating performs even better.

[0047] After screening multiple yeast strains, this invention selected *Cryptococcus facultative anaerobic* and *Issa mycoides* to form a co-fermentation strain. This co-fermentation strain can effectively metabolize various marine organic matter and algae, and can survive effectively in seawater with high salinity and fluctuating dissolved oxygen. It provides small molecule carbon for the inner layer of *Shewanella* and provides an anaerobic environment for the inner layer of *Shewanella*. This strain can also generate and transfer electric charge, assisting *Shewanella* in inhibiting the adhesion and growth of marine microorganisms.

[0048] 4. Corrosion resistance and shellfish adhesion performance testing of composite electrogenic bacterial biofilm anticorrosive coating

[0049] Five steel sheets (10cm×10cm×0.5cm, width×length×thickness) with the composite electrogenic biofilm anticorrosive coating and five uncoated steel sheets (10cm×30cm×0.5cm, width×length×thickness) were simultaneously placed 10m below the surface in Jiaozhou Bay, Qingdao. The uncoated steel sheets began to show algae adhesion after 10 days, and shellfish adhesion after approximately 25 days. After 365 days, the steel sheets corroded and were covered with a large amount of marine life. The coated steel sheets showed a small amount of algae adhesion after 90 days, covering 1 / 30 of the sheet (by weight). After 100 days, sporadic shellfish adhesion appeared. After 365 days, no steel sheet corrosion was observed, with only 1 / 5 of the steel sheets showing sporadic shellfish adhesion. This experiment further demonstrates that the coating effectively inhibits shellfish adhesion and has excellent seawater corrosion resistance.

[0050] 5. Experiments show that the structure of this coating does not increase the ship's drag and meets the national technical specifications for ship coatings.

[0051] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A composite electrogenic bacterial biofilm anti-corrosion coating for ship hull steel structures, characterized in that: The coating includes coating I (2) and coating II (3). Coating I (2) is applied to the outer surface of the steel structure (1) of the ship hull, and coating II (3) is applied to the surface of coating I (2). Coating I (2) includes diatom mud I and seawater salt-tolerant anaerobic electrogenic bacteria, which grow inside the pores of diatom mud I. Coating II (3) includes diatom mud II and seawater salt-tolerant facultative anaerobic yeast, which grow inside the pores of diatom mud II.

2. The anti-corrosion coating according to claim 1, characterized in that: The salt-tolerant anaerobic electrogenic bacteria in seawater is Shewanella, and the salt-tolerant facultative anaerobic yeast in seawater includes one or a combination of Cryptococcus and Isaac's yeast.

3. The anti-corrosion coating according to claim 1, characterized in that: The thickness of coating I (2) is 1-3 mm, and the thickness of coating II (3) is 1-3 mm.

4. A method for preparing the anti-corrosion coating according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Apply coating I (2) to the outer surface of the ship's steel structure. The coating I (2) includes diatomaceous earth I and salt-tolerant anaerobic electrogenic bacteria, which grow inside the pores of diatomaceous earth I. Step 2: Coating 2 (3) is applied to the surface of coating 1. Coating 2 (3) includes diatom mud II and facultative anaerobic microorganisms. The salt-tolerant facultative anaerobic yeast grows in the internal pores of diatom mud II.

5. The application of the anti-corrosion coating according to any one of claims 1-3, characterized in that: Using diatomaceous earth coating as a base, a complex microbial community grows within its pores, irreversibly adhering to the outer surface of the ship's hull through the diatomaceous earth base. This complex microbial community comprises an inner layer of domesticated and isolated salt-tolerant anaerobic electrogenic bacteria and their extracellular polymers, and an outer layer of salt-tolerant facultative anaerobic yeast and their extracellular polymers. On one hand, the outer layer of salt-tolerant facultative anaerobic yeast consumes dissolved oxygen in the water, metabolizing large marine organic molecules to form small organic molecules, thus maintaining an anaerobic environment for the inner layer of salt-tolerant anaerobic electrogenic bacteria. On the other hand, the inner layer of salt-tolerant anaerobic electrogenic bacteria utilizes the small organic molecules to generate charge, which is then transferred to the ship's steel structure, acting as a cathode to inhibit electrochemical corrosion of the steel structure in high-salinity seawater. Simultaneously, the salt-tolerant anaerobic electrogenic bacteria metabolize small acids, regulating the pH of the microenvironment and preventing corrosion of the steel structure by biological acids. Furthermore, the charge generated by the salt-tolerant anaerobic electrogenic bacteria is transferred to attached shellfish, causing them to secrete lectin metal ions (Ca) in their mucus. 2+ Or Mg 2+ The lectins are reduced to form Ca or Mg deposits, which deactivate the lectins, effectively inhibiting the adhesion and growth of marine shellfish and ensuring the bioadhesion safety of the ship's hull.

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