A Method and a Surface Treatment Agent for Preventing Biofouling on Surfaces under Water

This paper presents an environm centally friendly method of inhibiting biofouling especially acorn barnacles on surfaces under water by using nicotine and selenium in the form of Se（0）, or such a substance which can be converted into them. Both of the substances are necessary to oxygen dependent organisms and will be used after conversion, but are toxic in high doses. By adding the substances to paint or other surface treatment agent which marine surfaces are treated with, organisms which are trying to establish themselves on the surfaces will be exposed to so high doses, the reactions which the settling is based on are disturbed. When the substances leak out into the seas, they will act as environment protectors, as they promote the development of organisms. Nicotine is transformed to nicotine amid which is the reactive part in NADH and one of the most important substances for the transference of hydrogen. Selenite is reduced to Se（0）, also involved in the transport chain of hydrogen to reducible oxygen. However, large quantities Se（0） may disturb the reactions of sulphur b＇./binding to it and impairing the formation of S-S-bridges.

Antifouling Activities of Marine Bacteria Associated with Sponge (Sigmadocia sp.)

The present study aimed at assessing the antifouling activity of bacteria associated with marine sponges. A total of eight bacterial strains were isolated from the surface of sponge Sigmadocia sp., of them, SS02, SS05 and SS06 showed inhibitory activity against biofilm-forming bacteria. The extracts of these 3 strains considerably affected the extracellular polymeric substance producing ability and adhesion of biofilm-forming bacterial strains. In addition to disc diffusion assay, microalgal settlement assay was carried out with the extracts mixed with polyurethane wood polish and coated onto stainless steel coupons. The extract of strain SS05 showed strong microalgal settlement inhibitory activity. Strain SS05 was identified as Bacillus cereus based on its 16S rRNA gene. Metabolites of the bacterial strains associated with marine invertebrates promise to be developed into environment-friendly antifouling agents.

Advanced strategies for marine antifouling based on nanomaterial-enhanced functional PDMS coatings

Marine biofouling seriously affects human marine exploitation and transportation activities,to which marine antifouling(AF)coatings are considered to be the most cost-effective solution.Since the mid-20th century,human beings have dedicated their efforts on developing AF coatings with long cycle and high performance,leading to a large number of non-target organisms?distortion,death and marine environmental pollution.Polydimethylsiloxane(PDMS),is considered as one of the representative environment-friendly AF materials thanks to its non-toxic,hydrophobic,low surface energy and AF properties.However,PDMS AF coatings are prone to mechanical damage,weak adhesion strength to substrate,and poor static AF effect,which seriously restrict their use in the ocean.The rapid development of various nanomaterials provides an opportunity to enhance and improve the mechanical properties and antifouling properties of PDMS coating by embedding nanomaterials.Based on our research background and the problems faced in our laboratory,this article presents an overview of the current progress in the fields of PDMS composite coatings enhanced by different nanomaterials,with the discussion focused on the advantages and main bottlenecks currently encountered in this field.Finally,we propose an outlook,hoping to provide fundamental guidance for the development of marine AF field.

Bifunctional nanozyme activities of layered double hydroxide derived Co-A1-Ce mixed metal oxides for antibacterial application

Marine biofouling is an expensive problem that needs evolved chemical or physical antifouling strategies.However,most of the current antifouling materials that would damage the environment through metal leaching and bacteria resistance are being halted.Nanozyme is one kind of environmental antifouling materials through generating reactive oxygen species(ROS).We prepared various contents of CeO2 that could uniform disperse compounding with Co3 O4 and CoAl2 O4 to form a stable Co-Al-Ce mixed metal oxide(MMO) by a layered double hydroxide derived method.We find that coupling with CeO2 can improve the peroxidase(POx) activity.When the molar ratio of Ce is 2.5% and the calcination temperature is 200℃,the POx activity of Co-Al-Ce MMO is the best caused by the good dispersion of catalytically active components and the high specific area(150.10±4.95 m2/g).This novel Co-Al-Ce MMO also exhibits an antibacterial mode of action Gram-negative bacteria in near-neutral pH solution through generating ROS(mainly ·O2-)in the presence of H2 O2.Ce containing MMO can be utilized as potential green marine antifouling material.

Biocorrosion induced by red-tide alga-bacterium symbiosis and the biofouling induced by dissolved iron for carbon steel in marine environment

The assemblages of unicellular microalgae and bacteria in phytoplankton communities can generally result in biodeterioration of metals in marine environment.In this study,the self-promoted biofouling mechanism underneath red-tide alga Phaeodactylum tricornutum and its symbiotic bacterium Bacillus altitudinis was systematically revealed.The mutualistic interaction of the bacteria and algae quadrupled the corrosion rate in comparison to the individual effect of the bacterium or algal strain alone.Reversely,the corroded metal appeared to be an accelerator that can stimulate the activity of the P.tricornutum and aggravate the biological pollution based on the result of 62.3%up-regulation of the key photosynthesis genes.The corrosion-biofouling-accelerated corrosion-deteriorated biofouling formed a vicious cycle.

Dynamic Surface Antifouling Materials

The colonization of marine microorganisms,animals and plants on underwater surface forms marine biofouling.It has profound effects on marine industries.To solve the problem,we proposed a strategy of Dynamic Surface Antifouling(DSAF),i.e.,continuously changing surfaces can effectively inhibit biofouling organisms landing and adhering,and developed degradable polymer based marine antifouling material.The degradation of polymer chain enables the surface dynamic or self-renewing even on static conditions.The final degradation products of these polymers are low molecular weight molecules,and do not produce marine microplastics.Meanwhile,the degradable polymers act as carriers and controlled release systems for antifoulants,further improving the antifouling efficiency.This article reviews the development of dynamic surface antifouling materials.