The protection of immersed surfaces in the marine environment is a major economic, societal and environmental issue. All immersed surfaces undergo spontaneous biocolonisation. The consequences of this development onto surfaces are catastrophic. The main objectives of the scientific community are to develop new biocide-free antifouling coatings that meet increasingly stringent legislation and to replace traditional materials used in antifouling coatings such as PDMS with other materials that have the lowest possible environmental impact. However, understanding the physico-chemical properties that impact the adhesion of marine organisms remains a key issue in the development of new antifouling coatings. The CarbonaRA project is part of these dynamics. Biodegradable and/or biosourced polymers such as poly(trimethylene carbonate) have a low environmental impact. In addition to studying a new polymer as a matrix for antifouling coatings, the CarbonaRA project's major contribution is to induce differences in adhesion through physical properties in a decorrelated manner, with the chemical composition parameter remaining constant. It will therefore provide a better understanding of surface-microorganism interactions. The work envisaged in the multidisciplinary CarbonaRA project is based on the development of antifouling coatings based on poly(trimethylene carbonate) (PTMC) with modulable physicochemical properties. They are divided into 4 scientific tasks with the aim of i) to synthesize PTMC copolymers with different molar masses and structures to design coatings by UV cross-linking with variable mesh sizes and cross-linking node densities, ii) to characterize the physico-chemical properties of the coatings such as viscoelastic modulus, roughness or surface tension at different scales, (iii) to evaluate the antifouling properties and efficiency of the coatings on species present in the Gulf of Morbihan at the micro and macrobiological level by laboratory studies and in situ immersions, (iv) to measure the environmental impact of the new PTMC-based coatings by biodegradation studies and life cycle analysis. Due to the relatively new trend of biobased and/or biodegradable coatings for the marine environment, there is a huge knowledge gap in this field. The results of the project will fill the current knowledge gap and deepen the understanding of this technology. In addition, CarbonaRA will provide potential solutions to marine pollution by developing biodegradable antifouling coatings based on PTMC. The initial maturity level of the project (TRL scale) is low, but the results of the project could lead to new commercial opportunities in the marine paint market.

The purpose of the joint laboratory between the Laboratory of Marine Biotechnologies and Chemistry (LBCM-EA 3884) of the University of Bretagne-Sud and Nautix (SME, Guidel, 56) is to study the marine antifouling paints, from their design to their evaluation. A vast majority of these coatings, which are applied on immersed structures, prevent the proliferation of fouling such as seaweeds, bivalves etc. by action of toxic compounds (biocides) or surface effect (reduction of the adhesion strength of organisms). The development of antifouling paints involves not only high economic stakes (limitation of maintenance costs and gas consumption), but also technological and scientific challenges (numerous technological obstacles requiring an interdisciplinary approach), a societal issue (conformance to the current and future regulations) and an environmental responsibility (reduction of the emissions of toxic molecules, limitation of dissemination of invasive species). Areas of research to be covered by the common laboratory are, on the one hand, the design of innovative coatings and, on the other hand, the development of the tools required for their characterization and evaluation, both in terms of efficiency and environmental impact. Antifouling paints are complex formulations, composed of polymers bringing essential physical properties to the film (erosion, effect of surface and/or capacity at the leaching of molecules), and of additives conferring specific functions (colour, biocide action, permeability, porosity). The work will start from various Technology Readiness Levels (TRL). It will cover both aspects mentioned here above and have the objective of reaching short and medium-term goals in terms of efficiency, cost, environmental impact, compatibility with the current ways of prevention and maintenance. In a longer term, the aim is to propose fouling release solutions integrating macromolecules/molecules allowing anti-adhesive amphiphilic properties, imitating natural surfaces which are known to be free of colonization (i.e. seaweeds). The development of these products lies on the detailed knowledge of the phenomena involved in bio adhesion. Characterization tools must be developed to investigate the physical behaviour of films during immersion and/or facing stress (for example, shear stress during the movement of the structure or the action of the currents). Furthermore, the rapid evolution of the international and national environmental regulations makes the proof of the efficiency, as well as the evaluation of their environmental impact at various trophic levels of marine ecosystems, compulsory. Innovative ways of assessment will be an important area of investigation for the joint laboratory. As a summary, the joint laboratory will direct its research around three themes: i) develop innovative antifouling products with a low environmental impact, ii) design innovative fouling release solutions based on amphiphilic surfaces , iii) to develop innovative tools for the characterization and evaluation of coatings.

Biofoulings are associated to colonization of artificial submerged structures by aquatic organisms. This process induces adverse effects such as loss of hydrodynamism, weight increase of equipments, … Numerous toxic compounds (copper, arsenic) have been used during decades to avoid biofouling of ships, until organostatic substances were developed. According to their toxicity for marine environment and fauna, due to their non-specificity and biodegradability, EU has banned them since 2008. For this reason, a new strategy, focusing on environmental friendly molecules is requested aiming to provide coatings that release progressively active natural compounds, non toxic for environment. Such perspective is in full agreement with the REACH Framework as considering both efficient and environmental friendly products s well as human health and environment conservation issues. In tropical marine environment, deterrent molecules are recognized as one of the most efficient way for protection against predators or competition with other surfaces organisms (e.g corals, microalgae). Such active compounds are considered quite « infinite » (20 000 have been described to date), so of them for their antifouling activity. As a significant component of marine organisms, microalgae are a promising source of active natural substances, with biotechnological potential value. Growing microalgae is a worldwide project for various purposes actually e.g biofuel. Various aspects are required in order to provide both (i) a growing demand of ecological coatings (chemical, biological,…) and (ii) the variety of marine environment where they must be efficiently active against fouling organisms. BIOPAINTROP planned on a 36 months duration, aims to develop antifouling coatings with active biomolecules originating tropical marine resources (microalgae) from Reunion Island. 2 main objectives have been designated: (i) identification of active molecules from tropical microalgae and (ii) incorporation of these compounds in adequate coatings and confirm the efficiency of these products in both temperate and tropical marine environment. To reach the targeted results, a pluridisciplinary group has been set up with 7 teams with complementary expertises (biologist and microbiologist, chemist, physicochemist, specialist in biopolymers, paint producters, microalgae producters). BIOPAINTROP will provide significant progress in processing ecological antifouling coating incorporating natural tropical marine compounds. Moreover, the project will allow a better understanding of ecological processes between organisms. Such innovative products are requested by stakeholders in order to reduce environmental impacts of fishing, aquaculture, trading activities.

Since 2011, massive beachings of Sargassum have been occurring regularly on the Caribbean coast, from Brazil to Mexico and as far away as West Africa. By using a combination of field studies, ecological and physiological experiments and biotechnological processes, the project SAVE-C presents three objectives: (i) acquire basic information on Sargassum species constituting rafts in the nearshore, within bays and in beachings along a latitudinal gradient; (ii) collect and stabilize the biomass; (iii) valorize beachings in two sectors of activities, agriculture (biopesticides/biostimulants) and biomaterials (bioplastics/cartoons) from Sargassum matter. The project groups 15 partners including two partners in Mexico and Barbados. To reply to our questionnings, five workpackages (WP) were designed: WP1 assesses the associated diversity in Sargassum rafts, including environmental parameters in all regions studied. WP2 studies the functioning of rafts and the interactions developed between organisms with Sargassum species including foodweb and nitrogen transfer. WP3 investigates the life-cycle of Sargassum in term of growth, photosynthetic performances, the contamination by arsenic until the degradation process of fragments. WP4 permits to work with local collectivities for the collection of huge biomasses of Sargassum and propose solutions for the stabilization of the biomass before its uses. Finally, this biomass will be used in WP5 as raw material in two industrial sectors: Agriculture and Biomaterials. The consortium will diffuse results to funding Agencies and Caribbean populations, together with transfer to each territorial collectivity knowledge from this project and disseminate to diverse audiences (stakeholders, General Public, students) and participate to new local jobs in West Indies.