Control Of Marine Biofouling Research Articles

UV-C LED-induced cyclobutane pyrimidine dimer formation, lesion repair and mutagenesis in the biofilm-forming diatom, Navicula incerta

The use of ultraviolet-C (UV-C) irradiation in marine biofouling control is a relatively new and potentially disruptive technology. This study examined effects of UV-C exposure on the biofilm-forming diatom, Navicula incerta. UV-C-induced mutations were identified via Illumina HiSeq. A de novo genome was assembled from control sequences and reads from UV-C-exposed treatments were mapped to this genome, with a quantitative estimate of mutagenesis then derived from the frequency of single nucleotide polymorphisms. UV-C exposure increased cyclobutane pyrimidine dimer (CPD) abundance with a direct correlation between lesion formation and fluency. Cellular repair mechanisms gradually reduced CPDs over time, with the highest UV-C fluence treatments having the fastest repair rates. Mutation abundances were, however, negatively correlated with CPD abundance suggesting that UV-C exposure may influence lesion repair. The threshold fluence for CPD formation exceeding CPD repair was >1.27 J cm−2. Fluences >2.54 J cm−2 were predicted to inhibit repair mechanisms. While UV-C holds considerable promise for marine antifouling, diatoms are just one, albeit an important, component of marine biofouling communities. Determining fluence thresholds for other representative taxa, highlighting the most resistant, would allow UV-C treatments to be specifically tuned to target biofouling organisms, whilst limiting environmental effects and the power requirement.

Indole-functionalized polythiourethane/tetrapodal shaped ZnO nanocomposites for eco-friendly marine biofouling control

Antifouling coatings for marine use are a widely employed method for controlling the settlement and growth of unwanted aquatic organisms on surfaces. In this study, indole derivative N-(1H-5-bromo indole-3-ylmethyl) acrylamide (BIAM)-functionalized polythiourethane (PTU)/tetrapodal shaped zinc oxide (t-ZnO) nanocomposites (PTU/BIAM/t-ZnO) were synthesized through a Friedel–Crafts Alkylation reaction, thiol-ene click reaction and polyaddition reaction. Nanocomposites' surface characteristics, such as surface free energy, chemical composition, and surface morphology were investigated here. The mechanical characteristics and antifouling properties of the coating materials were also considered. These nanocomposites exhibited not only superior mechanical properties, due to the presence of both PTU and t-ZnO, but also promising antifouling properties owing to the incorporation of BIAM on their surfaces. The adhesion strength of the nanocomposites increased from 0.26 MPa to 0.68 MPa due to the incorporation of t-ZnO particles. Benefiting from the PTU matrix, the tensile strength of nanocomposite can reach over 57 MPa. The PTU/BIAM/t-ZnO nanocomposites demonstrated improved algae resistance and marine antifouling performance compared to the reference PTU/t-ZnO nanocomposite without indole derivative. The PTU/BIAM/t-ZnO nanocomposites exhibit resistance to fouling organisms due to the synergistic effect of the easy-to-clean characteristic of the PTU/t-ZnO and the reduction of the polar component of the surface free energy resulting from the inclusion of indole derivative BIAM on the surface. This, in turn, reduces the interaction between fouling organisms and the material surface. Furthermore, BIAM interferes with the homeostasis of cellular calcium ions, thereby hindering the attachment of fouling organisms. Under the combined action of PTU, BIAM, and t-ZnO, the synergistic effect of good antifouling properties, environmental compatibility, good mechanical properties and strong adhesion to the substrate was achieved.

Importance of Duration, Duty-Cycling and Thresholds for the Implementation of Ultraviolet C in Marine Biofouling Control

The introduction of a surface into the marine environment begins a process known as biofouling, which increases the weight and hydrodynamic drag of the fouled structure. This process is detrimental to maritime vessels and costs the industry ∼$150B in fuel and maintenance spending annually. Preventing the settlement of fouling organisms mitigates these issues and limits the spread of non-indigenous species (NIS). This is primarily achieved via antifouling paints. Ultraviolet light is a sterilization method used in water purification, food storage packaging, and within medical fields. Ultraviolet C (UV-C) radiation interacts with DNA to prevent growth, proliferation, and survival of bacteria, and biofilm formation. Recent progress in microelectronics technology has advanced the range of commercially available light-emitting diodes (LEDs) to include the UV wavelengths, and the reduced size and cost has allowed their integration into previously inaccessible locales. This study builds on recent progress in integrating UV-C LEDs into UV-lucent silicone tiles for fouling control. The operational cycle needed to prevent growth of Navicula incerta cells was determined. Constant irradiance at a peak of 5.77 μW/cm2 resulted in a significant reduction in diatoms within 2 h, and a 2 log and 3 log reduction after 48 h and 5 days, respectively. Duty cycling (pulsing) in all variations from 50 to 2.5%, indicated significant reductions in cell densities, and the lowest cycle could effectively reduce biofouling growth and increase the longevity of the LEDs for up to 45.6 years. Irradiance and exposure were altered over a set duration and indicated a restriction in growth between 0.01–0.82 J/cm2 and an increased mortality at irradiances > 2.65 J/cm2, suggesting an effective antifouling threshold between these dosages. The effective dosage for 1 log reduction in fouling was estimated to be 25 J/cm2 but varied according to irradiance delivery method. Effective dosage for a 1 log reduction between experimental methods was variable indicating that UV treatment of N. incerta departed from the Bunsen-Roscoe reciprocity law expectancy. The variation in densities at similar dosages could be explained with further investigation of DNA repair mechanisms. In conclusion, UV-B/C use was effective at all irradiances, including as low as 0.01 J/cm2, and holds considerable promise for marine biofouling control.

In Vitro Oxidative Crosslinking of Recombinant Barnacle Cyprid Cement Gland Proteins

Barnacle adhesion is a focus for fouling-control technologies as well as the development of bioinspired adhesives, although the mechanisms remain very poorly understood. The barnacle cypris larva is responsible for surface colonisation. Cyprids release cement from paired glands that contain proteins, carbohydrates and lipids, although further compositional details are scant. Several genes coding for cement gland-specific proteins were identified, but only one of these showed database homology. This was a lysyl oxidase-like protein (lcp_LOX). LOX-like enzymes have been previously identified in the proteome of adult barnacle cement secretory tissue. We attempted to produce recombinant LOX in E. coli, in order to identify its role in cyprid cement polymerisation. We also produced two other cement gland proteins (lcp3_36k_3B8 and lcp2_57k_2F5). lcp2_57k_2F5 contained 56 lysine residues and constituted a plausible substrate for LOX. While significant quantities of soluble lcp3_36k_3B8 and lcp2_57k_2F5 were produced in E. coli, production of stably soluble lcp_LOX failed. A commercially sourced human LOX catalysed the crosslinking of lcp2_57k_2F5 into putative dimers and trimers, and this reaction was inhibited by lcp3_36k_3B8. Inhibition of the lcp_LOX:lcp2_57k_2F5 reaction by lcp3_36k_3B8 appeared to be substrate specific, with no inhibitory effect on the oxidation of cadaverine by LOX. The results demonstrate a possible curing mechanism for barnacle cyprid cement and, thus, provide a basis for a more complete understanding of larval adhesion for targeted control of marine biofouling and adhesives for niche applications.

Assessment of the environmental compatibility and antifouling performance of an innovative biocidal and foul-release multifunctional marine coating

The control of marine biofouling has raised serious environmental concerns, thus the continuous release of toxic and persistent biocidal agents applied as anti-biofouling coatings have triggered the search for non-toxic strategies. However, most of them still lack rigorous evaluation of their ecotoxicity and antifouling effects under real scenarios and their correlation with simulated assays. In this work, the biocide releasing risk and ecotoxicity of a biocidal and foul-release polydimethylsiloxane (PDMS)-based marine coating containing grafted Econea biocide (<0.6 wt.%) were evaluated under simulated real mechanical wear conditions at a pilot-scale system, and under extreme wear scenarios (washability settings). The coating system demonstrated low environmental impact against the model Vibrio fischeri bacterium and marine algae, associated with the effective biocide grafting in the coating matrix and subsequent biocide release minimization. This multifunctional coating system also showed auspicious antifouling (AF) effects, with an AF performance index significantly higher (API > 89) than a single foul-release system (AF < 40) after two and half years at a real immersion scenario in the Portuguese shore of the Atlantic Ocean. These field results corroborated the antibiofilm performance evaluated with Pseudoalteromonas tunicata at simulated dynamic marine conditions after seven-week assays. This eco-friendly multifunctional strategy, validated by both simulated testing conditions and real field tests, is believed to be a powerful tool for the development of AF technologies and a potential contribution to the quest for new environmentally friendly antifouling solutions.

ZnO/Acrylic Polyurethane Nanocomposite Superhydrophobic Coating on Aluminum Substrate Obtained via Spraying and Co-Curing for the Control of Marine Biofouling

Biofouling is a costly and complex problem in the marine industry. Traditional anti-biofouling coatings based on the release of biocidal substances have caused serious environmental and health issues. Polymeric nanocomposite superhydrophobic coatings have attracted increasing attention worldwide as durable and ecofriendly alternatives to toxic anti-biofouling paints. However, the conventional procedures for preparing nanocomposite coatings still have some drawbacks. In particular, the nanoparticles on the surface of the coating are buried in the matrix resin, which greatly diminishes the anti-biofouling properties of the coating. To overcome these problems, in this paper a facile spraying and co-curing method was adopted to construct a superhydrophobic coating using acrylic polyurethane and a hydrophobic ZnO bactericidal suspension. The obtained coatings displayed excellent superhydrophobicity, robust abrasion resistance, and high stability in practical operation. Moreover, the synergistic effects of the ZnO bactericidal nanoparticles and the superhydrophobic coating are able to suppress marine algae adhesion and biofilm formation. Hence, the developed nanocomposite superhydrophobic coating can be applied as an effective anti-biofouling agent for applications in marine environments.

Characterization of silicon acrylic resin containing silica nanoparticles as candidate materials for antifouling and anticorrosion properties in seawater

Abstract The damage caused by marine fouling organisms to ships and underwater artificial equipment is becoming increasingly serious issue, and the prevention and control of marine biofouling has always been a research hotspot in marine coatings. Aiming at the problems of poor adhesion, long curing time and high curing temperature of low-surface energy marine antifouling coatings of organosilicon, a hydrophobic low-surface energy nano-SiO2/silicon acrylic resin nanocomposite coating was synthesized. The anticorrosive property of the composite coatings was analyzed by simulated seawater periodic immersion experiments. The gel permeation chromatography analysis showed that polydimethyl-siloxanes (PDMS) is involved in cross-linking reactions. The dynamic thermomechanical analysis indicated that the glass transition temperature of resin is 58 °C. The contact angle (CA) test showed that the CA of nanocomposite coating is 109.99°. All the detection results can support the excellent antifouling and anticorrosion performance of the low surface energy nanocomposite coatings.

Biofilm eradication by in situ generation of reactive chlorine species on nano-CuO surfaces

Herein, we constructed a nano-CuO film on copper foil for the in situ generation of reactive chlorine species (RCS) for the contact killing of bacteria and biofilm suppression and dispersal. Both Staphylococcus aureus and Escherichia coli were susceptible to this treatment. Additionally, we demonstrate the solid nano-CuO interface-based heterogeneous Fenton chemistry rather than leached copper-ion-based homogeneous Fenton chemistry is responsible for RCS generation and bacterial cytotoxicity. This process is modulated by the H2O2 and Cl− concentrations in bacterial growth environment. The potential applications for in situ generation of RCS might be the incorporation of CuO nanoparticles into functional food contact surfaces as well as coating materials for marine biofouling control.

Preparation and characterization of amphiphilic polymer coating for marine biofouling control

Biofouling is a major issue prevalent in marine industry resulting in losses in billions of dollars for repairing and maintenance. Coatings developed to tackle marine biofouling are either toxic towards environment or have shorter lifespan. Amphiphilic block copolymer coatings have gained wide attention recently to mitigate biofouling. In this work, performance of synthesized coating towards biofouling was studied. Hydroxyl terminated polydimethylsiloxane as hydrophobic and chitosan as hydrophilic moiety was used to synthesize the amphiphilic coating. Characterization of the prepared coating using Scanning Electron Microscopy (SEM) showed heterogeneous microstructure. Antifouling performance using egg white as the protein testing probe was done as it simulates the adhesives used by biofouling organism. Resistance to protein adhesion was seen on the surface of the coating. So, the developed environmental-friendly coating can be used effectively for the mitigation of marine biofouling.

Extraction of Protease Produced by Sea Mud Bacteria and Evaluation of Antifouling Performance

Enzyme-based antifouling coatings are potential alternative to traditional tributyltin-based coatings in the marine bio-fouling control depended on its environmental friendliness. Proteases are usually the key antifouling active components in enzyme based antifouling coatings. In this work, based on biological antagonism effect, a marine proteolytic bacterial strain of Bacillus velezensis was isolated from the sea mud, and denoted as SM-1. The scanning electron microscope (SEM) revealed that the bacteria are rod-shaped with length 1-1.3 μm. The protease-producing conditions of SM-1 were investigated, and it was found that the culture solution displays higher proteolytic activity under the culture conditions of 35°C, 10‰-20‰ salinity, pH 6–9 and more than 7d culture time. Moreover, the 25kDa protein was confirmed to be the main active component in the crude protease, which was revealed via the experiment of SDS-PAGE. The antifouling assay indicated that the protease SM-1 has remarkable effect on the decomposition of barnacle cement and diatom secretion, and also can effectively inhibit the attachment of barnacle cyprids, diatom and mussel byssus. Therefore, this protease potentially can be used as environmental-friendly antifoulant of enzyme-based marine antifouling coatings, and this work also provides a new approach to obtain antifouling protease via isolating proteolytic bacteria from the sea mud surrounding representative fouling organisms.

Furylchalcones as new potential marine antifoulants

The control of marine biofouling by copper-based antifouling paints has a negative impact on the environment. Accordingly, these paints are becoming less friendly in several countries and are being subjected to greater ecological control. Therefore, the efforts are focused on the search for new-environmentally compounds to replace the utilization of copper biocides. Six furylchalcones obtained by biomass building block (furfural) were synthesized in this work, e.g., 3-(furan-2-yl)-1-phenylprop-2-en-1-one (3b); 3-(5-methylfuran-2-yl)-1-phenylprop-2-en-1-one (3c); 3-(furan-2-yl)-1-p-tolylprop-2-en-1-one (3d); 3-(5-methylfuran-2-yl)-1-p-tolylprop-2-en-1-one (3e); 3-(furan-2-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (3f); 1-(2-hydroxyphenyl)-3-(5-methylfuran-2-yl)prop-2-en-1-one (3g). Antifouling paints containing these compounds were prepared at laboratory scale. In order to study antifouling paint performance, field trials were accomplished in Mar del Plata harbour (Argentina) during the summer. Furylchalcones were synthesized with high yields (˃ 87%) and the reaction was very selective (no competitive side reactions such as product decomposition, acetophenone condensation Cannizzaro's reaction, etc., were observed). Field trials revealed that paints containing furylchalcones showed strong antifouling effect on the fouling community, being 3d and 3g the most active against algae and calcareous tubeworms. The present work studies for the first time the significance of synthesizing furylchalcones from biomass building-blocks to generate new antifoulants to marine biofouling control.

Fabrication of Slippery Lubricant-Infused Porous Surface with High Underwater Transparency for the Control of Marine Biofouling.

Marine optical instruments are bearing serious biofouling problem, which affects the accuracy of data collected. To solve the biofouling problem of marine optical instruments, a novel instance of slippery lubricant-infused porous surface (SLIPS) with high underwater-transparency was designed over glass substrate via infusing lubricant into its porous microstructure fabricated with hydrothermal method. The advantage of SLIPS as antibiofouling strategy to marine optical instruments was proven by comparing its underwater optical and antibiofouling performances with three kinds of samples (hydrophilic glass sample, textured hydrophilic glass sample, and superhydrophobic glass sample). The modification of SLIPS enhances the underwater-transparency of glass sample within the wavelength of 500-800 nm, for the infusion of lubricant with lower refractive index than glass substrate. In contrast with hydrophilic surface, textured hydrophilic surface and superhydrophobic surface, SLIPS can significantly inhibit bacterial and algal settlements, thereby maintaining high underwater-transparency in both dynamic and static seawater. The inhibition of bacterial and algal settlements over SLIPS results from its liquid-like property. The contact angle hysteresis of water over SLIPS increases with immersion time in seawater under different conditions (static, dynamic, and vibration conditions). Both dynamic and vibration conditions accelerate the failure of SLIPS exposed in seawater. This research provides valuable information for solving biofouling problem of marine optical instruments with SLIPS.

Adhesive heparin coating for marine antifouling applications

The control of marine biofouling has gained significant attention because the uncontrolled adhesion of marine organisms onto synthetic surfaces leads to serious problems. Here, we demonstrate a facile method to inhibit the adhesion of marine organisms using the sulfated polysaccharide, heparin. Heparin was conjugated with an adhesive molecule, catechol, and the resulting adhesive heparin was used as a surface coating for stainless steel, a material commonly used for marine vessels. Immersion of stainless steel surfaces in a solution of adhesive heparin resulted in a stable heparin coating. The marine antifouling property of the surface was confirmed using marine diatom adhesion assays, which revealed that the adhesive heparin coating reduced diatom adhesion by ~75%, as compared with untreated surfaces.

Sulfobetaine-based polymer brushes in marine environment: Is there an effect of the polymerizable group on the antifouling performance?

Three different zwitterionic polymer brush coatings for marine biofouling control were prepared by surface-initiated atom transfer radical polymerization (ATRP) of sulfobetaine-based monomers including methacrylamide (SBMAm), vinylbenzene (SBVB) and vinylimidazolium (SBVI). None of these brush systems have been assessed regarding marine antifouling performance. Antifouling tests performed indicate that surfaces featuring these three brush systems substantially reduce the adhesion of the marine microalgae, Amphora coffeaeformis, and the settlement of cyprid larvae of the barnacle, Amphibalanus amphitrite, in a similar way, displaying comparable performance. Thus, it appears that the chemical structure of the polymerizable group has no substantial influence on marine antifouling performance.

Active Enzyme Nanocoatings Affect Settlement of Balanus amphitrite Barnacle Cyprids

AbstractBalanus amphitrite cyprids produce complex adhesive substances that enable their attachment to surfaces and impart a strong detachment resistance from most immersed substrata. The colonization of man‐made structures by barnacle cyprids and other marine organisms is a troublesome and costly phenomenon, for which controlling strategies are actively sought. In this work, we expand previous investigations about the susceptibility of cyprid adhesives to unpurified proteases in solution by evaluating the interplay between these secreted biomolecules and a surface‐confined purified protease. The strategy involved the covalent immobilization of the enzyme Subtilisin A to maleic anhydride copolymer thin films through the spontaneous reaction of anhydride moieties with lysine side chains. This enabled the production of bioactive layers of tunable enzyme surface concentration and activity, which were utilized to systematically evaluate the effect of the immobilized enzyme on cyprid settlement and exploratory behavior. Surfaces of increasing enzyme activity displayed a gradual decrease in cyprid settlement levels (approaching inhibition) as well as an increase in post‐settlement adhesion failure (evidenced by significant numbers of detached metamorphosed individuals). High activities of the bound enzyme also affected pre‐settlement behavior of cyprids, reducing the velocity and total distance moved while increasing the amount and speed of meander compared to the controls. The here‐reported low enzyme surface concentrations found to be remarkably effective at reducing cyprid settlement hold promise for the use of immobilized enzymes in the control of marine biofouling.

The control of marine biofouling on xerogel surfaces with nanometer-scale topography

Mixtures of n-octadecyltrimethoxysilane (C18, 1–5 mole-%), n-octyltriethoxysilane (C8) and tetraethoxysilane (TEOS) gave xerogel surfaces of varying topography. The 1:49:50 C18/C8/TEOS xerogel formed 100–400-nm-wide, 2–7-nm deep pores by AFM while coatings with ≥3% C18 were free of such features. Segregation of the coating into alkane-rich and alkane-deficient regions in the 1:49:50 C18/C8/TEOS xerogel was observed by IR microscopy. Immersion in ASW for 48 h gave no statistical difference in surface energy for the 1:49:50 C18/C8/TEOS xerogel and a significant increase for the 50:50 C8/TEOS xerogel. Settlement of barnacle cyprids and removal of juvenile barnacles, settlement of zoospores of the alga Ulva linza, and strength of attachment of 7-day sporelings were compared amongst the xerogel formulations. Settlement of barnacle cyprids was significantly lower in comparison to glass and polystyrene standards. The 1:49:50 and 3:47:50 C18/C8/TEOS xerogels were comparable to PDMSE with respect to removal of juvenile barnacles and sporeling biomass, respectively.

In situ ATR-IR spectroscopic and electron microscopic analyses of settlement secretions of Undaria pinnatifida kelp spores.

Knowledge about the settlement of marine organisms on substrates is important for the development of environmentally benign new methods for control of marine biofouling. The adhesion to substrates by spores of Undaria pinnatifida, a kelp species that is invasive to several countries, was studied by scanning electron and transmission electron microscopies (SEM/TEM) as well as by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. The IR spectra showed that adhesive secretion began approximately 15 min after initial settlement and that the adhesive bulk material contained protein and anionic polysaccharides. Energy dispersive X-ray microanalysis of the adhesive identified sulphur and phosphorus as well as calcium and magnesium ions, which facilitate the gelation of the anionic polysaccharides in the sea water. The adhesive may be secreted from Golgi bodies in the spore, which were imaged by TEM of spore thin sections. Additionally, an in situ settlement study on TiO(2) particle film by ATR-IR spectroscopy revealed the presence of phosphorylated moieties directly binding the substrate. The presence of anionic groups dominating the adhesive suggests that inhibition of spore adhesion will be favoured by negatively charged surfaces.

The role of surface energy and water wettability in aminoalkyl/fluorocarbon/hydrocarbon-modified xerogel surfaces in the control of marine biofouling

Xerogel films with uniform surface topogrophy, as determined by scanning electron microscopy, atomic force microscopy (AFM), and time-of-flight secondary ion mass spectrometry, were prepared from aminopropylsilyl-, fluorocarbonsilyl-, and hydrocarbonsilyl- containing precursors. Young's modulus was determined from AFM indentation measurements. The xerogel coatings gave reduced settlement of zoospores of the marine fouling alga Ulva compared to a poly(dimethylsiloxane) elastomer (PDMSE) standard. Increased settlement correlated with decreased water wettability as measured by the static water contact angle, θWs, or with decreased polar contribution (γP) to the surface free energy (γS) as measured by comprehensive contact angle analysis. The strength of attachment of 7-day sporelings (young plants) of Ulva on several of the xerogels was similar to that on PDMSE although no overall correlation was observed with either θWs or γS. For sporelings attached to the fluorocarbon/hydrocarbon-modified xerogels, the strength of attachment increased with increased water wettability. The aminopropyl-modified xerogels did not follow this trend.

Temperature dependent physicochemical properties of poly(N-isopropylacrylamide-co-N-(1-phenylethyl) acrylamide) thin films

The physicochemical properties of thermo-responsive polymer films are dynamically altered upon changes in environmental conditions. We report on the design and detailed characterization of a novel thermo-responsive polymer film with a temperature transition tuned to fit applications related to the control of marine biofouling. A copolymer consisting of poly(N-isopropylacrylamide) (PNIPAAm) and N-(1-phenylethyl) acrylamide (PEAAm) was synthesized and immobilized as a thin film onto Teflon AF surfaces using a low pressure argon plasma treatment. The temperature dependent physicochemical properties of the thermo-responsive film were thoroughly characterized and the impact of sea water on the film properties was investigated. The immobilized thermo-responsive film exhibits a reversible swelling/deswelling with temperature. Atomic force microscopy showed no morphological changes with varying temperature. Streaming current measurements performed above and below the transition temperature of the thermo-responsive hydrogel indicated that the charging of the polymer/aqueous solution interface is mainly determined by the preferential water ion adsorption at the Teflon AF surface. Inverse contact angles measured using captive air bubbles and analysed by axisymmetric drop shape analysis (ADSA) supported the intrinsic properties of the thermo-responsive film, as surface hydrophilicity decreased with increasing temperature. The advancing water contact angle decreased with increasing temperature, which may be explained by the different molecular mobility at different temperatures, allowing or hampering the re-orientation of hydrophobic segments at the solid–liquid and solid–fluid interfaces. These new films will allow investigations on the interaction of microorganisms with environmentally sensitive surfaces.

New approaches to Marine Biofouling Control

Biofouling control measures are dependant on the type of industry, type of industry, type of equipment, environment and the substratum. Cooling circuits of power plants invariably get fouled. Several biocides like chlorine, chlorine dioxide, ozone & organic biocides are being tried for fouling control. However chlorine has been the most sought after biocide due to its low cost, easy handling and quick degradation. The ban on tributyltin (TBT)-based paint products has been the cause of a major change in the antifouling paint industry. In the past decade, several competing technologies have reached the commercial market and claimed their effectiveness with respect to prevention of biofouling on ships and marine structures in an environmentally friendly manner. The interest in providing innovative anitfouling technologies has led to a large number of studies for improved understanding of the process and the principles underlyhing, biofouling of surfaces. The efficiency of the antifouling coating increased with the ability for controlled release of the biocide from the matrix which was demonstrated by the TBT SPC technology. In the search for alternate antifoulants, studies have been oriented in two ways i.e. Imitation of the natural antifouling process (natural product antifoulants) and the surface modification approach (low surface energy of the substrate of coating). Biofouling in power plants leads to flock blockage, increased condenser backpressure. In the search for marine natural product as antifoulants several antifouling compounds have been successfully identified, howeever compatibility of these compounds into commercial coatings with the desired leaching rates has been a stumbling block for their success. Some opractical criteria to be considered in the development of such coating is compatibility of compounds with polymer matrixes, environmental effects, legislation and registration of the compounds. Among the low surface energy materials tested the best was found to be a silicone elastomer poly (dimethylsiloxane) PDMS. The work initiated by NIOT to understand and study marine fouling is discussed in this paper. Further other alternative technologies towards environmentally favourable antifouling systems are outlined.