DE102010039568A1 - Surface coating, useful for preventing fouling in aquatic environment, comprises one phototrophic microorganism in a formulation comprising polyurethane component - Google Patents

Abstract

Surface coating comprises at least one phototrophic microorganism in a formulation comprising a polyurethane component.

Description

The invention relates to a surface coating comprising certain living microorganisms for preventing the growth of surfaces and a method for producing the surface coating, as well as the use of the system for preventing fouling exposed to aqueous environment surfaces.

The growth of surfaces with a variety of microbial, as well as other, higher organisms, such as shells, mushrooms, etc. is commonly known by the term of fouling, or specifically biological fouling.

Fouling is particularly disadvantageous in a number of cases because it provides the surface affected by it with negative properties. Such negative properties are, for example, the negative change in the flow resistance of the overgrown surface when it flows around with a surrounding fluid, or the simple reduction of the free flow cross section when closed surfaces are affected. Furthermore, the o. G. Fouling the corrosion of metallic surfaces.

Fouling of ship hulls is a major economic problem, especially in industrial shipping, as it significantly increases the flow resistance of the ship as it moves, resulting in a significant increase in fuel consumption of ships. This additional consumption is generally tolerated to some extent until the ship is periodically put into dry dock for exemption from fouling. Thus, in addition to the additional fuel costs, the operators also incur costs for the regular exemption of the ships from said fouling. Alternatively, the ship can only be moved at a slower rate for the same fuel consumption, which is also an economic disadvantage, since the operating times are extended accordingly without further value.

The same is true in the case of pipelines that essentially carry water containing organic matter. Again, the operators are forced either to choose significantly increased pipe diameter for a reasonable service life, which is disadvantageous in terms of increased investment costs, or to clean the pipes at regular intervals. However, at least, the flow line operators must expend more energy to compensate for the additional pressure loss of the lines due to fouling.

It is now widely known from biological research that a large number of aquatic and in particular marine organisms produce a large number of substances which in each case adversely affect at least one other species of the same habitat ( PC Wright et al. "Exploitation of marine algae: biogenic compounds for potential antifouling applications, Planta, 2004, 219: 561-578 ).

In this context, approximately in the US 2004/0258655 A1 discloses that such substances can also be obtained from aquatic organisms and that these substances are useful as a component of surface coatings.

The general problem of such surface coatings is the fact that the surface coating contains only a certain amount of the substances that prevent or limit fouling. Thus, the treated surface is still subject to fouling after some time.

In the US 5,919,689 discloses a composition comprising at least one microorganism, or a mixture of an amyolytic or proteolytic enzyme with a microorganism. Further, the composition may comprise an inorganic salt in catalytic amounts.

The microorganisms contained in the composition are disclosed to be safe and it is concretely disclosed that such microorganisms may be derived from, for example, the genus Bacilli, Escherichia coli or Pseudomonas or other known microorganisms. It is further disclosed that the invention can be practiced without the microorganisms. Essential for the revelation of US 5,919,689 is, however, that the microorganisms used can produce amylases or proteases.

In the US 5,919,689 Thus, a composition is disclosed which either prevents fouling by physical mechanisms or, in the case of a biological approach, relies on the action of the amylases or proteases. It is obviously irrelevant whether the enzymes are affected by the microorganisms be produced in the composition, or already present in the composition. This mode of action according to the disclosure of US 5,919,689 is based on the assumption that this can prevent or minimize the formation of a primary film on the surface. The US 5,919,689 further discloses, however, that other mechanisms may also result in the formation of fouling on the surface, thus following the disclosure of U.S. Pat US 5,919,689 can not be prevented. In particular, higher organisms such as macroscopic algae, shells, etc. are therefore not hindered from adhering to the surface.

The composition of US 5,919,689 is further disadvantageous because, while it is disclosed that the microorganisms used are to be selected so that they are viable in aquatic habitat, but in particular a use of the disclosed microorganisms from the US 5,919,689 In the aquatic environment questionable, since all microorganisms disclosed in milk were tested for their effectiveness and all micro-organisms just not of aquatic origin. A conclusion on an effect in the aquatic environment is thus also questionable. Milk has a distinctly different salt concentration from many aquatic environments, a distinctly different pH and, moreover, a significantly different proportion of organic constituents which act as a substrate for the microorganisms. In addition, only an effect against the proteins of milk and starch is detected.

Furthermore, the statement that the microorganisms used should be non-hazardous since the disclosed microorganisms are, as stated, not of aquatic origin and thus a release of these may possibly interfere with the biological system of the aquatic environment.

The US 5,919,689 Therefore, it does not disclose to a person skilled in the art how to achieve an effect against fouling in the aquatic environment by means of non-hazardous microorganisms. In particular, the composition of the US 5,919,689 disadvantageous because, if anything, it can only affect fouling by a protein and starch based film.

In the US 2004/0009159 that on the US 5,919,689 Reference is made to a composition disclosed in addition to those in the US 5,919,689 disclosed microorganisms may also contain yeasts and fungi. Further, it is disclosed that the composition may have a multi-layered structure, wherein each layer may have a thickness of 3 to 4 mm. Also the effect of the composition from the US 2004/0009159 is based on the action of enzymes that can now be cellulases, lyases, hydrolases or other hydrolytic enzymes in addition to amylases and proteases. However, the desired effect aims again at the destruction of a possibly resulting primary film of proteins and polysaccharides, which are to be cleaved by means of the enzymes. As a result, only one effect in starch solutions is measured.

The revelation of US 2004/0009159 So has the same disadvantages as those of US 5,919,689 ,

It is therefore still the object to provide a surface coating that effectively prevents fouling and not only adhesion of protein films and films of polysaccharides even in the environment of open waters and whose composition is also harmless from a biological point of view.

It has now surprisingly been found that a surface coating for the prevention of fouling in the aquatic environment, characterized in that it comprises at least one phototrophic microorganism in a formulation comprising a polyurethane component, can solve this task for the first time in a particularly advantageous manner.

The invention relates to a surface coating for preventing fouling in the aquatic environment, characterized in that it comprises at least one phototrophic microorganism in a formulation comprising a polyurethane component.

An aquatic environment in the context of any environment is defined as essentially water. A special environment in which this invention proves to be particularly advantageous is the marine environment, so z. Oceans and seas. Other aquatic environments in which the invention also proves to be particularly advantageous include rivers, lakes, or other open or closed, standing or flowing waters.

Essential for the advantageous mode of action of the invention and its preferred further developments is only the fact that the respective aquatic environment is a habitat for at least one phototrophic microorganism of this invention.

In the context of the present invention, phototrophic microorganism refers to a microorganism which, by means of a photosynthetic process, is capable of accumulating carbon dioxide from its environment for the gain of cell mass by using light.

Preferred phototrophic microorganisms are species or subspecies of the Cyanobacteria Division, and / or species or subspecies of a microorganism of the Department of Chlorophyceae and / or species or subspecies of a microorganism of the Chrysophyceae Division.

In the context of the present invention, the species or subspecies of a cyanobacterial microorganism refers to any species or subspecies of the cyanobacteria that can be obtained from an aquatic or terrestrial habitat. Preferred species and subspecies of a microorganism from the cyanobacteria division are those which produce at least one substance that is either growth-inhibiting, repellent or fatal to at least one other species or subspecies of any aquatic habitat.

Particularly preferred species or subspecies from the cyanobacteria division are those selected from the list consisting of Calothrix brevissima, Fischerella muscicola, Gomphosphaeria aponina, Hapalosiphon fontinalis, Hyella caespitose, Lyngbya majuscula, Nostoc commune, Nostoclinckia, Nostoc muscorum, Nostoc punctiforme, Nostoc spongiaeforme , Nostoc spongiaeforme var.tenue, Oscillatoria sp., Phormidium tenue, Scytonema Hofmanni, Scytonema ocellatum, Scytonema pseudohofmanni, Synechocystis leopoliensis, Tolypothrix tenuis and Tolypothrix tjipanasensis.

Very particular preference is given to those species or subspecies from the cyanobacteria division selected from the list containing Lyngbya majuscula, Scytonema Hofmanni and Nostoc punctiforme.

Such species or subspecies are particularly advantageous because they produce at least one of the above-mentioned substances in sufficiently large quantities and because they all originate from the marine habitat, so that in case of damage to the surface coating and any resulting release of the cyanobacteria into the environment, the environment is not significantly burdened by this. Furthermore, the selection of such cyanobacteria ensures that they are adapted to the conditions of their environment, so that they also have a constant release of the desired substances.

In the context of the present invention, the type or subspecies of a microorganism from the Department of Chlorophyceae means any species or subspecies of the division of the Chlorophyceae that can be obtained from an aquatic or terrestrial habitat. Preferred species and subspecies of a microorganism from the Department of Chlorophyceae are those that produce at least one substance that acts on at least one other species or subspecies from the same habitat, either growth-inhibiting, repulsive or deadly.

Particularly preferred species or subspecies from the department of Chlorophyceae are those selected from the list consisting of Chlorococcum HS-101, Chlorococcum sp., Chlorokybus atmophyticus, Dictyosphaerium pulchellum, Klebsormidium crenulatum, Pleurastrum terrestre, Staurastrum gracile, Chlamydomonas reinhardii, Chlorella minutissima (357) , Chlorella minutissima (360), Chlorella minutissima (361), Chlorella sp. (313), Chlorella sp. (381), Chiorella sp. (458), Desmococcus olivaceus (324), Desmococcus olivaceus (343), Dunaliella primolecta, Hydrodictyum reticulatum, Protosiphon botryoides, Scenedesmus sp. (469), Scenedesmus sp. (540) and Stichococcus mirabilis.

Substances which produce the phototrophic microorganisms according to the present invention are, for example, those selected from the list of substance classes consisting of fungicides, algicides, antibiotics.

In the context of the present invention, the species or subspecies of a microorganism from the Chrysophyceae Division refers to any species or subspecies of the Chrysophyceae Division that can be obtained from an aquatic or terrestrial habitat. Preferred species and subspecies of a microorganism of the Chrysophyceae Division are those that produce at least one substance that is either growth-inhibiting, repellent or fatal to at least one other species or subspecies of any aquatic habitat.

Polyurethane component in the context of the present invention refers to any material comprising an organic polymer having at least two repeats of a -NH-CO-O- group.

Non-exhaustive examples of such materials are polyurethane coatings, such as lacquers commercially available based on Desmodur ^® and / or Desmophen ^® (manufacturer: Bayer MaterialScience AG, 51368 Leverkusen).

Further particularly suitable and basically known polyurethane coatings are described in: Meier-Westhues et al, "Polyurethane Paints, Adhesives and Sealants", Hannover, Vincentz Network 2007, pp. 92-139 as far as they are compatible with the microorganisms and processable.

The new surface coating and its preferred developments usually contain in particular an absolute proportion of 0.001 to 2 wt .-% per species or subspecies of the microorganisms (based on the dry biomass) at the time of application to a surface.

Since the microorganisms are subject to proliferation and dying over time, the absolute proportion may change over time without adversely affecting the principal effectiveness of the invention.

In a preferred development of the present invention, the surface coating according to the invention comprises at least one kind or subspecies of a microorganism from the cyanobacteria division and at least one kind or subspecies of a microorganism from the division of the chlorophyceae.

Within the preferred refinement of the surface coating, it particularly preferably comprises more than one type or subspecies from at least one of the two compartments.

In a particularly preferred further development of the surface coating according to the invention, it comprises at least one type or subspecies of a microorganism from the cyanobacteria division and at least one species or subspecies of a microorganism from the division of the chlorophyceae and at least one species or subspecies of a microorganism from the division of the chrysophyceae.

Within the particularly preferred further development of the surface coating, it particularly preferably comprises more than one kind or subspecies from at least one of the three compartments

A particularly preferred further development of the surface coating according to the invention is characterized in that it comprises the species Chlamydomonas reinhardtii, Lyngbya majuscula, Nostoc punctiforme, Ochromonas danica and Scytonema hofmanni.

The preferred and particularly preferred further development described above are particularly advantageous because, in particular depending on the environment, the relative proportion of the respective species and subspecies of the cyanobacteria division to the relative proportion of the respective species and subspecies of the department Chlorophyceae to the relative proportion of the respective species and subspecies the Department of Chrysophyceae shifts, as they grow in principle under other environmental conditions.

This property of the surface coating is particularly advantageous, as it allows for at least two different aquatic environments in which the surface coating is located in each case a division of the microorganisms can preferably produce substances that counteract fouling.

In addition, it is possible that at least one of the species or subspecies from the departments of cyanobacteria and / or chlorophyceae and / or chrysophyceae is also capable of energy in addition to the aforementioned photosynthetic property also by glycolytic or other metabolism which does not rely on the energy of light is to be recovered so that the surface coating can survive even longer periods of darkness. This is particularly advantageous in coatings on the underside of ship hulls, in closed containers or similar environments.

The invention will be described in more detail below with reference to examples and figures, without, however, restricting them to them.

1 shows the determined according to Example 2 growth ratios (B) over time (t) in days. The values of the vegetation ratios (B) are indicated above the respective diagram bar. The dashed line represents the value of 1 or below which no improvement in the antifouling activity of the surface coating according to the invention is observed.

2 shows the determined according to Example 4 growth ratios (B) over time (t) in days. The values of the vegetation ratios (B) are indicated above the respective diagram bar. The dashed line represents the value 1 or below which no improvement in the antifouling activity of the surface coating according to the invention is observed.

Examples

Example 1: Production of a First Surface Coating According to the Invention

The embedding took place at the onset of the logarithmic growth phase of the microorganism O. danica (SAG-933-7), which was determined by means of temporally resolved determination of the dry biomass in an aqueous suspension of the microorganism.

A sample corresponding to 1 mg of dry biomass was taken from the aqueous suspension of the microorganism and centrifuged at 14,000 rpm for 5 minutes. The resulting pellet was redispersed to homogeneity in 100 μl.

The suspension thus obtained was homogeneously mixed with 0.9 g of a precrosslinked, 1-component polyurethane dispersion and 75 .mu.l of the microorganism lacquer mixture were applied by means of a paint dumbbell (100 .mu.m distance) to a polycarbonate film slide (Makrofol DE1-1, 18 mm.times 16 mm) and dried for 16 min at room temperature.

The vitality of the embedded microorganisms was confirmed by endogenous chlorophyll fluorescence.

Example 2 Test for Anti-Fouling Activity of the Surface Coating According to Example 1

The polycarbonate film obtained according to Example 1 with a surface coating according to the invention, a blank sample (uncoated polycarbonate film of the same type) and a blank sample (polycarbonate film according to Example 1 but without addition of the microorganism) were placed in an aquarium (20 × 55 × 90) for a period of ten days cm), which was filled with commercial aquarium water and was open to the environment.

Circulation and fumigation of the water was ensured by an aquarium pump (Fa .: Aquabee, type: UP 1000). The aquarium was illuminated with 25-30 μmol m ² s ^-1 by 4 fluorescent tubes (OSRAM, type Lumilux Cool White). The test was carried out at ambient pressure (1013 hPa) and ambient temperature (23 ° C).

At intervals, the polycarbonate film with surface coating according to the invention, the reference sample and the blank sample were removed from the test system and examined by means of a photometer (Analytic Jena, SPECOR 210) at a wavelength of 750 nm in order to draw conclusions about the growth of the samples.

Each measurement takes place at ten different locations of the respective film. Accordingly, each film was measured ten times. An averaging of the measurement points allowed the representation of the extent of biological growth over time.

The measured values of the polycarbonate film with surface coating according to the invention according to Example 1 were corrected in each case by the measured value of the blank sample.

In 1 the growth ratios (B) are shown over time, which illustrate the multiple of the fouling of the blank sample in comparison to the polycarbonate film with inventive surface coating according to Example 1.

The dashed line of 1 represents the value 1. Values greater than 1 mean that the blank sample was overgrown by just that factor more than the polycarbonate film with inventive Surface coating according to Example 1. From a value of greater than 1, it is thus possible to speak of an antifouling activity of the surface coating according to the invention.

The polycarbonate film with surface coating according to the invention according to Example 1 had growth ratios many times higher than 1 over the entire experimental period. The surface coating according to the invention was thus particularly active against fouling.

Example 3: Production of a Second Surface Coating According to the Invention

A surface coating was prepared according to Example 1, with the only difference that, instead of the microorganism used there, a mixture of the microorganisms according to Table 2 was used. Table 1: Microorganisms used according to Example 3 Department Art / subspecies origin Chlorophyceae Chlamydomonas reinhardtii SAG - 83.81 Cyanobacteria Lyngbya majuscula CCAP - 1446/4 Cyanobacteria Nostoc punctiforme SAG - 6979 Chrysophyceae Ochromona danica SAG - 933-7 Cyanobacteria Scytonema hofmanni UTEX - 2349

Since the microorganisms Nostoc punctiforme, Lyngbya majuscula did not grow in homogeneous suspension, they were homogenized before embedding with an Ultraturrax (30 sec, 24000 rpm).

Otherwise, the samples were pooled at the mass ratio given in Table 2, centrifuged at 14,000 rpm for 5 min, and the resulting pellet dispersed in 100 μl of PBS buffer solution pH 7.4 by vortexing to homogeneity. Table 2: Dry biomass (BTM) of the embedded phototrophic microorganisms organism BTM [mg] C. reinhardtii 1 L. majuscula 1 N. punctiform 1 O. danica 1 S. hofmanni 0.1

Example 4: Test for anit-fouling activity of the surface coating according to Example 3

The procedure was analogous to Example 2, with the only difference that now the samples prepared in the context of Example 3 were measured. The results are the same as in the case of Example 3 in FIG 2 shown.

In 2 Thus, again fouling ratios over time are shown, which illustrate the multiple of the fouling of the blank sample in comparison to the polycarbonate film with inventive surface coating according to Example 3.

The dashed line of 2 represents the value 1. Values greater than 1 mean that the blank sample was overgrown by just that factor more than the polycarbonate film with surface coating according to the invention according to Example 3. From a value of greater than 1 can thus be spoken of an antifouling activity of the surface coating according to the invention become.

Polycarbonate film with surface coating according to the invention according to Example 3 had growth ratios many times higher than 1 over the entire experimental period. The surface coating according to the invention was thus particularly active against fouling.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2004/0258655 A1 [0007]
• US 5919689 [0009, 0010, 0011, 0011, 0011, 0011, 0012, 0012, 0014, 0014, 0015, 0015, 0016]
• US 2004/0009159 [0015, 0015, 0016]

Cited non-patent literature

• PC Wright et al. "Exploitation of marine algae: biogenic compounds for potential antifouling applications, Planta, 2004, 219: 561-578 [0006]
• Meier-Westhues et al, "Polyurethane Paints, Adhesives and Sealants", Hannover, Vincentz Network 2007, pp. 92-139 [0034]

Claims (9)

Surface coating for the prevention of fouling in the aquatic environment, characterized in that it comprises at least one phototrophic microorganism in a formulation comprising a polyurethane component. Surface coating according to claim 1, characterized in that at least one phototrophic microorganism is a species or subspecies from the department of Chlorophyceae. Surface coating according to one of claims 1 or 2, characterized in that at least one phototrophic microorganism is a species or subspecies of a microorganism from the cyanobacteria division. Surface coating according to one of claims 1 to 3, characterized in that at least one phototrophic microorganism is a species or subspecies of a microorganism from the department of Chrysophyceae. Surface coating according to claim 3, characterized in that the surface coating comprises more than one species or subspecies of at least one of the two divisions of the chlorophyceae and cyanobacteria. Surface coating according to claim 4, characterized in that the surface coating comprises more than one species or subspecies of at least one of the three divisions of the Chlorophyceae, Cyanobacteria and Chrysophyceae. Surface coating according to claim 6, characterized in that it comprises the species Chlamydomonas reinhardtii, Lyngbya majuscula, Nostoc punctiforme, Ochromonas danica and Scytonema hofmanni. Surface coating according to one of the preceding claims, characterized in that the absolute proportion per species or subspecies of the microorganisms from 0.001 to 2 wt .-% (based on the dry biomass) at the time of application to a surface. Surface coating according to one of the preceding claims, characterized in that the polyurethane component comprises an organic polymer having at least two repeats of an -NH-CO-O- group.

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