Composition and microsphere for the remediation of polluted sites, soils and aqueous environments.

Abstract

The invention relates to a powder composition comprising an alkali-earth metal peroxide, aerobic alkalophilic or alkalotolerant saprophytic microorganisms, nutrients for these microorganisms, and optionally a base; and a solution as well as microspheres, their preparation methods, and their uses in the remediation of environments such as soils and aqueous media. Figure for the abstract: no figure

Description

Title of the invention: Composition and microsphere for the remediation of polluted sites, soils and aqueous environments.

[0001] The present invention relates to a composition in powder form, a solution as well as microspheres, their preparation processes and their uses in the depollution of environments such as soils and aqueous environments.

[0002] Pollution generated by industrial activities, agricultural activities, the large-scale exploitation of hydrocarbons, and other human activities poses risks to marine and terrestrial ecosystems, as well as to human health. For example, 75% of terrestrial soils are estimated to be polluted. This soil pollution is not insignificant and leads to an alteration of soil biodiversity, a reduction in organic matter and the soil's capacity to act as a filter, resulting in the contamination of water stored in soils and groundwater. Therefore, the remediation of soils and aquatic environments is a crucial issue.

[0003] To date, solutions are being implemented to combat soil and water pollution, both upstream and downstream, for the remediation of these environments, whether through off-site, on-site, or in-situ remediation methods. Remediation methods can be diverse, such as biological remediation, which includes biochemical remediation, or physico-chemical remediation, which includes various extraction techniques (by suction, electricity, heat, etc.), or even remediation by soil replacement.

[0004] Biochemical remediation is one of the alternatives used for the decontamination of an environment such as soil or an aqueous environment. Biochemical remediation consists of decontaminating these environments, notably through the use of microorganisms capable of degrading complex molecules.

[0005] However, biochemical remediation has inherent limitations, particularly regarding the constant supply of elements necessary for the development and maintenance of microorganisms. Indeed, the bioavailability of oxygen is an important factor for the initial growth of microorganisms. Nevertheless, this bioavailability is limited and difficult to control over time. Furthermore, biochemical remediation requires the operator to intentionally and prior to modify chemical reaction parameters over time, such as pH and temperature, which will depend on the quantity of pollutants present in the environment to be remediated. Consequently, all these drawbacks lead to limited technical results in terms of environmental pollution control and a significant financial cost.

[0006] The inventors' work has demonstrated that it is possible to develop a composition that promotes the growth of microorganisms capable of oxidizing pollutants present in soils and aquatic environments, as well as the gradual and controlled release of elements necessary for their activities, particularly hydrogen peroxide. Indeed, the release of hydrogen peroxide contributes directly or indirectly to the biodegradation of polluting organic compounds. Furthermore, the growth of microorganisms, through their metabolism, enables biodegradation via the metabolites and enzymes they secrete.

[0007] The invention therefore relates in particular to a composition in powder form comprising: - 1 to 50% by mass of an alkaline earth metal peroxide, - from 0.5 to 50% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 10 to 90% by mass of nutrient(s) for microorganisms, - 0 to 2% by mass of a base, the percentages by mass being given on the mass of the composition in powder form.

[0008] In this application, unless otherwise specified, all numerical values ​​given are understood to include bounds.

[0009] By "in powder form", we mean a composition in the form of particles.

[0010] Preferably, the particles have a size between 85 and 120, preferably between 90 and 110, more preferably between 95 and 100 pm.

[0011] By "particle size" we mean the largest dimension of the particle.

[0012] According to the invention, the powder composition comprises between 1 and 50% by mass of an alkaline earth metal peroxide, expressed on the total mass of the powder composition.

[0013] By "alkaline earth metal peroxide" is meant the reaction product between an alkaline earth metal and peroxide.

[0014] The alkaline earth metals are chosen from the group consisting of beryllium, magnesium, calcium, strontium, barium and radium.

[0015] Preferably, the alkaline earth metal peroxide is chosen from magnesium peroxide (MgO2), calcium peroxide (CaO2) or mixtures thereof, more preferably, the alkaline earth metal peroxide is calcium peroxide (CaO2).

[0016] Advantageously, the composition in powder form comprises between 5 and 40% by mass of an alkaline earth metal peroxide, preferably between 10 and 30% by mass, more preferably between 12 and 25% such as for example between 15 and 20% by mass of an alkaline earth metal peroxide, expressed on the total mass of the composition in powder form.

[0017] According to the invention, the powder composition comprises between 0.5 and 50% by mass of microorganisms, expressed on the total mass of the powder composition.

[0018] Advantageously, the composition in powder form comprises between 0.5 and 40% by mass of microorganisms, preferably between 1 and 40% by mass of microorganisms, more preferably between 1 and 30%, such as for example between 5 and 28% by mass of microorganisms, expressed on the total mass of the composition in powder form.

[0019] By "microorganism" is meant a microscopic living organism invisible to the naked eye. The microorganism may be a bacterium, an archaebacteria, a virus, a protist, a plant (such as an alga), an animal (such as a protozoan) or a fungus.

[0020] By “saprophyte” we mean a plant, animal, fungal or bacterial organism capable of feeding on decomposing organic matter.

[0021] Preferably, the saprophytic microorganism is of fungal (mushroom) or bacterial (bacteria) origin.

[0022] By "aerobic" we mean an organism that uses oxygen to grow.

[0023] By "alkalophile" is meant a microorganism that develops in basic environments, that is to say in environments with a pH greater than 7.

[0024] By “aiealotolerant”, we mean a microorganism that can develop in environments having a basic pH, that is to say in environments having a pH greater than 7.

[0025] The development of these microorganisms will allow, through their metabolisms, the secretion of metabolites and enzymes capable of lowering the pH of the environment in which the microorganism grows.

[0026] More specifically, these enzymes, secreted by microorganisms, are hydrolases and / or oxidoreductases.

[0027] Examples of hydrolases include esterases such as lipases and / or carboxylesterases; peptidases such as subtilisins; glucoside hydrolases and / or phosphatases; cellulases and / or hemicellulases.

[0028] Examples of oxidoreductases include peroxidases such as lignin peroxidases and / or manganese peroxidases; Glucose-Methanol- Choline oxidoreductases; reductases; monooxygenases; dioxygenases; laccases; catalases; oxidases such as glyoxal oxidases, multi-copper oxidases, alcohol oxygenases and / or aldehyde oxygenases.

[0029] Preferably, the secreted enzymes are peroxidases (lignin peroxidases and / or manganese peroxidases and / or versatile peroxidases), catalases and / or laccases.

[0030] Preferably, the aerobic alkalophilic or aiealotolerant saprophytic microorganisms are fungi, which may be from the same genus or several genera, the same species or several species. More preferably, the aerobic alkalophilic or aiealotolerant saprophytic fungus is chosen from among the ascomycetes and basidiomycetes.

[0031] Preferably, the composition in powder form in which the aerobic alkalophilic or alkalotolerant saprophytic microorganisms are fungi, said fungi being of genera selected from the group consisting of Acremonium, Aspergillus, Fusarium, Coprinus, Penicillium, Pleurotus, Trichoderma, Gliocladium, Phialophora, Stachylidium, Stilhella and their mixtures.

[0032] Preferably, the aerobic alkaliphilic or alkali-tolerant saprophytic fungi are of a species chosen from the group consisting of Acremonium altematum, Acremonium furcatum, Acremonium sp.6, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Fusarium oxysporum, Fusarium solani, Coprinus comatus, Coprinus cinereus, Coprinus friesii, Penicillium chrysogenum, Penicillium janthinellum, Penicillium digitatum, Penicillium simplicissimum, Penicillium veruculosum peyronel, Pleurotus ostreatus, Pleurotus eryngii, Pleurotus ulmarius, Pleurotus pulmonarius, Pleurotus sajor saju, Pleurotus sp. Florida, Trichoderma viride, Trichoderma harzianum, Trichoderma asperellum, Trichoderma virens, Trichoderma longibrachiatum, Trichoderma koningii, Gliocladium cibotii, Phialophora geniculata, Stachylidium bicolor and Stilbella annulata and mixtures thereof.

[0033] More preferably, the aerobic alkalophilic or alkalotolerant saprophytic fungi are of a species chosen from the group consisting of Aspergillus flavus, Fusarium oxysporum, Fusarium solani, Coprinus comatus, Coprinus cinereus, Coprinus friesii and their mixtures.

[0034] The composition comprises at least one species of aerobic, alkalophilic or alkalotolerant saprophytic fungi. However, other fungi and / or bacteria may be added to the composition in powder form.

[0035] These other fungi may be aerobic, alkalophilic, or alkalotolerant saprophytic fungi as indicated above, or other fungi. "Other fungi" means at least one fungus of a species that is not aerobic, alkalophilic, or alkalotolerant saprophytic.

[0036] As an example of other fungi, one can cite fungi that can produce melanins such as Melanocarpus albomyes. These fungi advantageously produce laccases in a basic medium which can directly oxidize organic components.

[0037] On peut également citer des champignons acidophiles non alcalotolérants tels que ceux des genres Agaricus, Agrocybe, Allescheriella, Amanita, Armillaria, Anthracophyllum, Antrodia, Aureobasisium, Bjerkandera, Boletus, Candida, Cantharellus, Chaetomium, Clitocybe, Collybia, Coriolopsis, Cortinarius, Cunninghamella, Daedaela, Debaryomyces, Dichomitus, Dipodascus, Flamulina, Fistulina, Funalia, Galerina, Ganoderma, Gautiera, Gloeophyllum, Glomus, Gomphidius, Grifola, Hydnellum, Hydnum, Hypholoma, Irpex, Kuehneromyces, Kretzschmaria, Laccaria, Lactarius, Laetiporus, Leccinum, Lentinus, Lepista, Lycoperdon, Macrocybe, Macrolepiota, Marasmiellus, Marasmius, Morchella, Neolentinus, Omphalotus, Paecilomyces, Paxillus, Perenniporia, Phanerochaete, Phlebia, Pholiota, Poria, Pycnoporus, Radiigera, Rozites, Russula, Sarcosphaera, Scedosporium, Schizophyllum, Sporotrichum, Stachybotrys, Stemphylium, Stropharia, Suillus, Trametes, Thelephora, Trichosporum, Tricholoma, Volvarielia,Xerocomus and their mixtures.

[0038] Preferably, the acidophilic, non-alkalotolerant mushrooms are those of a species chosen from the group consisting of Agaricus avensis, Agaricus bisporus, Agaricus bitorquis, Agaricus brasiliensis, Agaricus bresadolanus, Agaricus brunescens, Agaricus campestris, Agaricus involutus, Agaricus semotus, Agaricus silvicola, Agaricus aestivalis, Agaricus macrosporus, Agrocybe aegerita, Agrocybe praecox, Allescheriella sp., Amanita muscaria, Amanita rubescens, Armillaria mellea, Anthracophyllum discolor, Antrodia radiculosa, Aureobasisium pullulons, Bjerkandera adusta, Boletus badius, Boletus edulis, Boletus variegatus, Candida boidinii, Candida lipolytica, Cantharellus cibarius, Cantharellus tubaeformis, Chaetomium globosum, Clitocybe inversa, Clitocybe decembris, Clitocybe nebularis, Collybia dryophila, Coriolopsis polyzona, Cortinarius eliator, Cunninghamella elegans, Daedaela quercina, Debaryomyces castelli, Debaryomyces marasmus, Dichomitus squalens, Dipodascus aggregatus,Flamulina velutipes, Fistulina hepatica, Funalia gallica, Galerina vittiformis, Ganoderma lucidum, Ganoderma Applatum, Gautiera crispa, Gloeophyllum sepiarium, Glomus intraradices, Gomphidius glutinosus, Grifola frondosa, Hydnum rufescens, Hydnum repandum, Hypholoma capnoïdes, Hypholoma udorinus, Hypholoma fasciculare, Hypholoma sublateritium, Irpex lacteus, Kuehneromyces mutabilis, Kretzschmaria deusta, Laccaria fratema, Laccaria amethystina, Laccaria laccata, Laccaria proxima, Lactarius helvus, Lactarius turpis, Laetiporus sulphureus, Leccinum aurantiacum, Leccinum , crocipodium, Leccinum scabrum, Lentinus edodes, Lentinus tigrinus, Lentinus subnudus, Lentinus strigosus, Lepista nebularis, Lepista nuda, Lycoperdon periatum, Macrocybe titans, Macrolepiota excoiata, Macrolepiota gracilenta, Macrolepiota procera, Macrolepiota Rachodes, Marasmiellus troyanus, Marasmiellus palmivorus, Marasmiellus inoderma, Marasmiellus istambuliss, Marasmiellus Candidus, Marasmiellus opacus, Marasmiellus flaccidus, Marasmiellus tenerrimus, Marasmiellus ramealis, Marasmiellus juniperinus Murill, Marasmius oreades, Morchella esculenta, Morchella atretomentosa, Neolentinus lepideus, Omphalotus illudens, Paecilomyces lilacinus, Paxillus involutus, Paxillus atretomentosus, Perenniporia medulla-panis, Phanerochaete chrysosporium, Phanerochaete magnaliae, Phlebia brevispora, Podospora anserina, Pholiota chocenensis, Pholiota aurivella, Pholiota conissans, Pholiota alnicola, Pholiota gummosa, Pholiota brunnescens, Pholiota castanea, Pholiota highlandensis, Pholiota molesta,Pholiota microspora, Pholiota squarrosa, Poria cinescens, Pycnoporus cinnabarinus, Radiigera astrogleba, R07.iles caperatus, Russula densifolia, Russula nigricans, Russula Purpurea, Russula cyanoxantha, Saccaromyces cerevisiae, Sarcosphaera coronaria, Scedosporium apiospermum, Schizophyllum commune, Sporotrichum pruinosum, Stachybotrys chartarum, Stachybotrys chlorohalonata, Stemphylium loti, Stropharia coronilla, Stropharia rugoso annulata, Suillus luteus, Suillus grevillei, Suillus variegatus, Suillus tomentosus, Trametes Versicolor, Trametes trogii, Thelephora terrestris, Trichosporum mucoïdes, Tricholoma magnivelare, Tricholoma terreum, Volvarielia speciosa, Xerocomus badius, Xerocomus chrysenteron and their mixtures. ,

[0039] More preferably, the acidophilic, non-alkalotolerant fungus is chosen from the species Agrocybe aegerita, Agrocybe praecox, Allescheriella sp., Armillaria mellea, Bjerkandera adusta, Clitocybe nebularis, Cortinarius eliator, Daedaela quercina, Flamulina velutipes, Fistulina hepatica, Funalia gallica, Ganoderma lucidum, Ganoderma Applatum, Glomus intraradices, Grifola frondosa, Hydnum rufescens, Hydnum repandum, Hypholoma capnoïdes, Hypholoma udorinus, Hypholoma fasciculare, Hypholoma sublateritium, Irpex lacteus, Kuehneromyces mutabilis, Laccaria fratema, Laccaria amethystina, Laccaria laccata, Lace aria proxima, Lactarius helvus, Lactarius turpis, Laetiporus sulphureus, Lentinus edodes, Lepista nebularis, Lepista nuda, Macrocybe titans, Macrolepiota procera, Marasmiellus troyanus, Marasmiellus palmivorus, Marasmiellus inoderma, Marasmiellus Candidus, Marasmius oreades, Paxillus involutus, Phanerochaete chrysosporium, Podospora anserina, Pholiota chocenensis,Pholiota aurivella, Pholiota conissans, Pholiota alnicola, Pholiota microspora, Pholiota squarrosa, Pycnoporus cinnabarinus, Russula densifolia, Russula nigricans, Russula Purpurea, Russula cyanoxantha, Schizophyllum commu, Stropla annugo, Stropla annugo , luteus, Suillus grevillei, Suillus variegatus, Suillus tomentosus, Trametes Versicolor, Trametes trogii, Thelephora terrestris, Tricholoma magnivelare, Tricholoma terreum, Volvarielia speciosa and their mixtures.

[0040] When several mushrooms of different species are introduced into the composition in powder form, we speak of a "consortium" of mushrooms.

[0041] Optionally, the fungal consortium may also comprise bacteria.

[0042] Advantageously, a fungal consortium comprises 2 species of fungi, preferably 3 species of fungi. The fungal consortium may, for example, comprise 3 to 5 species of fungi.

[0043] Preferably, the consortium of fungi may, in particular, be composed of three species, one species being chosen from each of the groups below: - group 1: Coprinus spp, Marasmius spp, Kuehneromyces spp, - group 2: Trametes spp, Ganoderma spp, Phanerochaete spp, - group 3: Russula spp, Lactarius spp, Suillus spp.

[0044] More preferably, the fungal consortium may be composed of the species Coprinus comatus, Trametes versicolor and Lactarius laccata.

[0045] Alternatively, the fungal consortium may consist of a mixture of Fusarium species such as, for example, Fusarium oxysporum and Fusarium solani.

[0046] The bacteria, for their part, can be of a genus chosen from the group consisting of Acinetobacter, Bacillus, Citrobacter, Enterobacter, Pseudomonas, Streptomycescl their mixtures.

[0047] Preferably, the bacteria are of species chosen from the group consisting of Acinetobacter calcaoceticus, Bacillus cereus, Bacillus stearothermophilus, Citrobacter spp, Enterobacter spp, Pseudomonas aeruginosa, Pseudomonas ovalis, Pseudomonas putida, Streptomyces spp (such as Streptomyces Badius, Streptomyces viridosporus) and mixtures thereof.

[0048] According to the invention, the powder composition comprises between 10 and 90% by mass of nutritive ingredient(s), expressed on the total mass of the powder composition.

[0049] Advantageously, the composition in powder form comprises between 20 and 85% by mass of nutritive ingredient(s), preferably between 30 and 80% by mass of nutritive ingredient(s), more preferably between 40 and 70%, such as for example between 50 and 60% by mass of nutritive ingredient(s), expressed on the total mass of the composition in powder form.

[0050] By "nutrient ingredient" is meant an ingredient necessary for the growth of microorganisms. Preferably, the nutrient ingredient is chosen from the group consisting of carbohydrates, protein sources or mixtures thereof.

[0051] By “carbohydrates”, we mean in particular glucose, dextrose, maltodextrin, fructose, galactose, lactose, sucrose, maltose and / or sucrose.

[0052] By “protein source”, we mean in particular peptones and more particularly soy peptones or casein peptones.

[0053] The composition in powder form comprises between 0 and 2% by mass of a base, expressed on the total mass of the composition in powder form.

[0054] More particularly, the powder composition optionally comprises between 0.1 and 2% by mass of a base, expressed on the total mass of the powder composition.

[0055] By "base" we mean a compound which, in an aqueous medium, is capable of capturing one or more protons.

[0056] Preferably, the base is a strong base. The base is preferably chosen from sodium hydroxide (NaOH), also called caustic soda, potassium hydroxide (KOH), also called potash, or mixtures thereof. Preferably, the base is sodium hydroxide.

[0057] Advantageously, the composition in powder form optionally comprises between 0.1 and 1% by mass of a base, preferably between 0.1 and 0.5%, more preferably between 0.1 and 0.4%, such as for example between 0.1 and 0.3% by mass of a base, expressed on the total mass of the composition in powder form.

[0058] Adding a base to the composition in powder form will stabilize said composition.

[0059] The powder composition according to the invention can be used in different ways depending on the environment to be decontaminated.

[0060] By environment to be decontaminated, we are referring more particularly to environments of the type of wastewater and / or soils, in particular those polluted by organic pollutants.

[0061] Indeed, if the environment to be decontaminated is an aqueous medium, for example, wastewater, the powder composition can be spread directly into this environment. Alternatively, if the environment to be decontaminated is a non-aqueous medium, for example, soil, the powder composition can be spread directly into this environment. However, the addition of water to the non-aqueous medium to be decontaminated may then be necessary. Such an addition of water may result, for example, from rain, watering, etc.

[0062] In the presence of water, the alkaline earth metal peroxide of the composition will successively release dioxygen and hydrogen peroxide, via the modulation of the pH function by the microorganism, which will allow the degradation of organic pollutants present in the environment to be depolluted.

[0063] Without wishing to be bound by any theory, the applicant believes that initially, at a basic pH, the progressive and controlled release of dioxygen will This allows for the initial growth of the microorganism through the dissociation, upon contact with water, of the alkaline earth metal peroxide. The microorganisms present in the mixture will then grow and, through their metabolism, promote the release of metabolites and enzymes that oxidize polluting compounds. This secretion of metabolites will also induce a gradual decrease in pH, which will modify the dissociation reaction of the alkaline earth metal peroxide and thus allow the release of hydrogen peroxide. This release of hydrogen peroxide will directly and indirectly promote the degradation of organic pollutants present in the environment to be decontaminated.

[0064] Depollution by hydrogen peroxide can be done in three ways, by direct contact, by chemical catalysis and by biological catalysis.

[0065] Direct contact pollution control occurs through a redox reaction between an electron donor and acceptor, i.e., between an oxidant (reduced) and a reductant (oxidized). Direct contact pollution control depends on the oxidizing and reducing potential of hydrogen peroxide and the pollutant, and therefore on the environment to be treated.

[0066] Chemical catalysis pollution control is achieved through the reaction of a metal such as iron with hydrogen peroxide to produce OH radicals. These OH radicals, being unstable, will oxidize the organic and inorganic compounds in the environment to be treated.

[0067] Bio-catalytic depollution, on the other hand, is carried out via a reaction between enzymes secreted by bacteria or fungi, such as peroxidases, catalases, laccases, which catalyze the reaction of hydrogen peroxide with a compound to be depolluted.

[0068] Consequently, hydrogen peroxide can degrade environmental pollutants, such as total petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, and furans, by oxidation. This degradation by oxidation can be complete, producing CO2 and water, or incomplete, producing a non-toxic organic compound.

[0069] For example, depending on the pH of the aqueous composition, calcium peroxide (CaO2) in contact with water (H2O) will dissociate into hydrogen peroxide (H2O2) or dioxygen (O2). Indeed, at an acidic pH, that is, a pH below 7, the dissociation of alkaline earth metal peroxide (CaO2) into hydrogen peroxide (H2O2) is favored over dioxygen (O2). Conversely, at a basic pH, that is, a pH above 7, the dissociation of alkaline earth metal peroxide (CaO2) into dioxygen (O2) is favored over hydrogen peroxide (H2O2).

[0070] The composition in powder form includes, for example: - 5 to 40% by mass of an alkaline earth metal peroxide, preferably CaO2 - from 0.5 to 40% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 20 to 85% by mass of nutrient(s) for microorganisms, - optionally 0.10 to 1% by mass of a base, preferably sodium hydroxide, the percentages by mass being given on the mass of the composition in powder form.

[0071] According to an advantageous embodiment, the powder composition according to the invention comprises: - 10 to 30% by mass of an alkaline earth metal peroxide, preferably CaO2, - 1 to 40% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 30 to 80% by mass of nutrient(s) for microorganisms, - optionally 0.10 to 0.50% by mass of a base, preferably sodium hydroxide, the percentages by mass being given on the mass of the composition in powder form.

[0072] Preferably, the powder composition according to the invention comprises: - 12 to 25% by mass of CaO2, - 1 to 30% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 40 to 70% by mass of nutrient(s) for microorganisms, - optionally 0.10 to 0.40% by mass of sodium hydroxide, the percentages by mass being given on the mass of the composition in powder form.

[0073] Advantageously, the powder composition according to the invention comprises an iron salt.

[0074] Without wishing to be bound by any theory, the applicant believes that the addition of an iron salt to the composition allows the release of OH radicals and its use in pollution control, as described above.

[0075] Preferably, the iron salt can be chosen from the group consisting of ferrous salt and ferric salt.

[0076] By “ferrous salt”, we mean an iron salt comprising divalent iron, that is to say having an oxidation state of +11.

[0077] By “ferric salt”, we mean an iron salt comprising trivalent iron, that is to say having an oxidation state +III.

[0078] Preferably, the iron salt is chosen from iron sulfate, iron(II) oxide or ferrous oxide FeO, iron(III) oxide or ferric oxide Fe2O3, hydrated ferric oxide (Fe2O3.H2O), or mixtures thereof. A mixture of iron salts may be a mixture of pure iron salts or in combination with other elements.

[0079] As an example of a mixture of salts, which can be found in the form of ores, we can cite "magnetite" (Fe3O4), hematite (Fe2O3), or limonite (Fe2O3.xH2O).

[0080] Advantageously, the powder composition according to the invention comprises between 1 and 70% by mass of iron salt, preferably between 5 and 60% by mass of iron salt, more preferably between 10 and 50% by mass of iron salt, expressed on the total mass of the powder composition.

[0081] Advantageously, the powder composition can be diluted before spreading. Therefore, the invention also relates to a method for preparing a powder composition by mixing alkaline earth metal peroxide, aerobic alkalophilic or alkalotolerant saprophytic microorganisms, nutrient ingredient(s) and optionally the base.

[0082] According to a first embodiment of the composition preparation process, the alkaline earth metal peroxide, the aerobic alkalophilic or alkalotolerant saprophytic microorganisms, the nutrient ingredient(s), and optionally the base are each individually in powder form. A simple mixing of the powders is then carried out.

[0083] According to a second embodiment of the composition preparation process, a first mixing step is carried out in the presence of water. For example, a fungal culture in liquid medium can be prepared, comprising water, aerobic alkalophilic or alkalotolerant saprophytic microorganisms, and the nutrient(s). A second mixing step then allows the addition of the alkaline earth metal peroxide and optionally the base, thus obtaining a solution. Finally, a drying and / or grinding step of the solution yields the composition in powder form.

[0084] Said processes may further include a step of incorporating iron salt.

[0085] The invention also relates to a solution comprising the composition in powder form and water.

[0086] The term "water" means tap water, mineral water, ultrapure water, or demineralized water. Preferably, the water is demineralized water.

[0087] More specifically, the solution comprises: - 50 to 95% by mass of water, - 2 to 10% by mass of an alkaline earth metal peroxide, - 1 to 20% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 1 to 30% by mass of nutrient ingredient(s) for microorganisms, - 0 to 0.2% by mass of a base, the percentages by mass being given on the mass of the solution.

[0088] In the solution, with the exception of the contents, the alkaline earth metal peroxide, the aerobic alkalophilic or aloe-tolerant saprophytic microorganisms, the nutrient ingredient(s) and the optional base are as described above, including preferred and advantageous modes.

[0089] Advantageously, the solution comprises between 55 and 89% by mass of water, preferably between 60 and 82% by mass of water, more preferably between 65 and 79% by mass of water, expressed on the total mass of the solution.

[0090] Advantageously, the solution comprises between 3 and 8% by mass of an alkaline earth metal peroxide, preferably between 4 and 6% by mass, more preferably between 4.5 and 5.5% by mass of an alkaline earth metal peroxide, expressed on the total mass of the solution.

[0091] Advantageously, the solution comprises between 2 and 15% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, preferably between 3 and 12% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, more preferably between 4 and 10% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, expressed on the total mass of the solution.

[0092] Advantageously, the solution comprises between 5 and 25% by mass of nutrient ingredient(s), preferably between 10 and 20% by mass of nutrient ingredient(s), more preferably between 12 and 18% by mass of nutrient ingredient(s), expressed on the total mass of the solution.

[0093] The solution comprises between 0 and 0.2% by mass of a base, expressed on the total mass of solution.

[0094] More specifically, the solution optionally comprises between 0.01 and 0.2% by mass of a base, preferably between 0.02 and 0.1% by mass, more preferably between 0.03 and 0.07% by mass, and even more preferably between 0.04 and 0.05% by mass of a base, expressed as a percentage of the total mass of the solution. The addition of sodium hydroxide to the solution can, in particular, prevent the premature initiation of the dissociation reaction of CaO2 into dioxygen.

[0095] The solution may also include an iron salt, as defined previously.

[0096] Advantageously, if an iron salt is added, then the solution comprises between 3 and 16% by mass of iron salt, preferably between 4 and 12% by mass of iron salt, more preferably, between 4.5 and 11%, such as for example between 5 and 10% by mass of iron salt expressed on the total mass of the solution.

[0097] The invention also relates to a method of preparing the solution, by mixing water, alkaline earth metal peroxide, alkalotolerant aerobic saprophytic microorganisms, nutrient ingredient(s) and optionally the base.

[0098] According to a first embodiment of the process for preparing the solution, the latter may include a step of supplying the composition in powder form as defined above, and a step of mixing said composition with water to obtain the solution.

[0099] The solution according to the invention can also be prepared directly without going through the preparation of a composition in powder form.

[0100] Indeed, according to a second embodiment of the solution preparation process, certain ingredients of the composition in powder form may be pre-mixed with water in a first mixing step. For example, the nutrient(s) may be mixed with water to form a culture medium. Alkalophilic or alkalotolerant aerobic saprophytic microorganisms may then be added to form a fungal culture in liquid medium. Finally, in a second mixing step, the alkaline earth metal peroxide and optionally the base may be added to form the solution.

[0101] Said method for preparing the solution may further include a step of incorporating iron salt.

[0102] The solution may also include additional ingredients to prepare a mixture enabling the manufacture of microspheres by crosslinking a drop of the mixture.

[0103] The invention therefore also proposes a mixture comprising the solution and a monovalent salt of alginate.

[0104] By "monovalent alginate salt" is meant a deprotonated alginic acid salt. Alginic acid and its derivatives such as alginates are polysaccharides derived from brown algae. A monovalent alginate salt is capable of crosslinking in the presence of a divalent salt to form a thermostable divalent alginate salt hydrogel.

[0105] Advantageously, the mixture comprises between 0.5 and 5% by mass of monovalent alginate salt, preferably between 0.75 and 4% by mass of monovalent alginate salt, more preferably between 1 and 3% by mass of monovalent alginate salt, expressed on the total mass of the mixture.

[0106] Preferably, the monovalent alginate salt is chosen from the group consisting of sodium alginate, potassium alginate, magnesium alginate and ammonium alginate

[0107] More preferably, the monovalent alginate salt is sodium alginate. Sodium alginate can be chosen from the group consisting of high viscosity sodium alginate (viscosity at 25°C, at 1% (w / v), greater than 3500 mPa.s), medium viscosity sodium alginate (viscosity at 25°C, at 1% (w / v), between 240-3500 mPa.s) and low viscosity sodium alginate (viscosity at 25°C, at 1% (w / v), less than 240 mPa.s).

[0108] Preferably, sodium alginate is high viscosity sodium alginate.

[0109] The mixture may further comprise a chelator.

[0110] By "chelator" is meant a molecule which has the capacity to form, with a positive metal ion, a stable compound. Advantageously, the chelator is a soluble and non-toxic compound.

[0111] Preferably, the chelating agent is chosen from the group consisting of phytic acid, ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N'-disuccinic acid (EDDS), citric acid, oxalic acid, and sodium hexametaphosphate. More preferably, the chelating agent is phytic acid.

[0112] The chelator makes it possible in particular to prevent the immediate crosslinking of the monovalent salt of alginate and of the alkaline earth metal peroxide in the mixture.

[0113] The mixture may comprise between 0.10 and 2% by mass of chelator, preferably between 0.25 and 1.5% by mass of chelator, more preferably between 0.3 and 1% by mass of chelator, expressed on the total mass of the mixture.

[0114] Advantageously, the mixture may also include humic acid. The mixture may include between 0.5 and 5% by mass of humic acid, preferably between 1 and 4% by mass of humic acid, more preferably between 1.5 and 3% by mass of humic acid, expressed on a basis of the total mass of the mixture.

[0115] The invention also relates to a method of preparing the mixture by mixing the solution with the monovalent alginate salt.

[0116] Said process for preparing the mixture may further include a step of incorporating the chelator and / or humic acid.

[0117] The invention also relates to a microsphere comprising: - from 3 to 50% by mass of water, - 0.5 to 40% by mass of an alkaline earth metal peroxide, - 2 to 35% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 30 to 90% by mass of nutrient(s) for microorganisms, - 0.01 to 5% by mass of a base, - from 0.1 to 7% by mass of a divalent alginate salt, the mass percentages being given on the mass of the microsphere.

[0118] In the microsphere, with the exception of the contents, water, alkaline earth metal peroxide, aerobic alkalophilic or alkalotolerant saprophytic microorganisms, nutrient ingredient(s) and base are as described above, including preferred and advantageous modes.

[0119] By "microsphere" is meant a substantially spherical object having a homogeneous structure. Advantageously, the microsphere has a diameter between 200 and 6000 pm, preferably between 500 and 4000 pm, more preferably between 800 and 3000 pm.

[0120] By means of the crosslinking of the monovalent alginate salt into a divalent alginate salt, the microsphere according to the invention is in the form of a hydrogel.

[0121] The term "divalent alginate salt" preferably refers to calcium alginate, magnesium alginate, ammonium alginate and / or potassium alginate. More preferably, the divalent alginate salt is calcium alginate.

[0122] According to the invention, the microsphere comprises between 3 and 50% by mass of water, preferably between 5 and 30% by mass of water, more preferably between 10 and 25% by mass of water, expressed on the total mass of the microsphere.

[0123] According to the invention, the microsphere comprises between 0.5 and 40% by mass of an alkaline earth metal peroxide, preferably between 2 and 30% by mass, more preferably between 5 and 25% by mass of an alkaline earth metal peroxide, expressed on the total mass of the microsphere.

[0124] According to the invention, the microsphere comprises between 2 and 35% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, preferably between 7 and 30% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, more preferably between 15 and 25% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, expressed on the total mass of the microsphere.

[0125] According to the invention, the microsphere comprises between 30 and 90% by mass of nutritive ingredient(s), preferably between 35 and 80% by mass of nutritive ingredient(s), more preferably between 40 and 68% by mass of nutritive ingredient(s), expressed on the total mass of the microsphere.

[0126] According to the invention, the microsphere comprises between 0.01 and 5% by mass of a base, preferably between 0.02 and 3% by mass of a base, more preferably between 0.05 and 2% by mass of a base, expressed on the total mass of the microsphere.

[0127] According to the invention, the microsphere comprises between 0.1 and 7% by mass of a divalent alginate salt, preferably between 0.5 and 6% by mass of a divalent salt of alginate, more preferably, between 1 and 5% by mass of a divalent alginate salt, expressed on the total mass of the microsphere.

[0128] The microsphere according to the invention may further comprise a chelating agent as defined above and / or humic acid. Humic acid, in particular, enhances the aesthetic appearance of the microsphere.

[0129] The microsphere will enable the decontamination of the environment. Water present in the environment to be decontaminated will be drawn into the microsphere by capillary action, initiating the dissociation of the alkaline earth metal peroxide into dioxygen. This dioxygen then allows the development of microorganisms. The base present in the microsphere advantageously maintains its pH between 9 and 12 in contact with the water, which promotes the dissociation of the alkaline earth metal peroxide into dioxygen. This will allow aerobic, alkalophilic or alkalotolerant saprophytic microorganisms to develop in the presence of the dioxygen thus released.

[0130] The microsphere is likely to be obtained by crosslinking the mixture in the presence of a divalent salt.

[0131] The divalent salt is an alkaline earth metal salt. Preferably, the divalent salt is a calcium or magnesium salt.

[0132] Advantageously, when the microsphere is obtained by crosslinking the mixture, the mixture will contain a base. Indeed, without being bound by any particular theory, it is considered that when obtaining microspheres by crosslinking the mixture, the base present in the mixture will advantageously prevent interactions between the alkaline earth metal of the alkaline earth metal peroxide and the monovalent alginate salt, as premature, undesirable crosslinking of the monovalent alginate salt could result from these interactions. In fact, the dissociation of the alkaline earth metal peroxide into dioxygen can release the alkaline earth metal, and thus initiate the crosslinking of the monovalent alginate salt. The incorporation of the base will allow it to react with the released alkaline earth metal to form a metal hydroxide, and prevent crosslinking.

[0133] The invention also relates to a method for obtaining a microsphere comprising a crosslinking step of the monovalent alginate salt contained in a drop of a mixture.

[0134] Preferably, the microsphere is obtained by immersing a drop of the mixture in a crosslinking bath.

[0135] By "crosslinking bath" is meant a bath prepared with water, preferably demineralized water, and a divalent salt such as a calcium salt or a magnesium salt. The crosslinking bath crosslinks the monovalent alginate salt present in the mixture. Indeed, the monovalent alginate salt reacts with the divalent cation from the divalent salt to form a three-dimensional network and thus form the microsphere.

[0136] Preferably, the crosslinking bath is prepared with water and calcium chloride (CaCl2). Advantageously, the crosslinking bath has a Ca2+ or CaCl2 concentration between 0.05M and 2M, preferably between 0.5M and 1.5M, more preferably between 0.1M and 1M.

[0137] Advantageously, the mixture is immersed in the crosslinking bath by a drip system to form the microspheres. Typically, the drip system for the mixture can be implemented using a pump. For example, the drip system can be used with a diaphragm pump.

[0138] Advantageously, the crosslinking bath is agitated.

[0139] Advantageously, the pH of the crosslinking bath is between 7 and 9. As an example, the pH of the crosslinking bath can be maintained between 7 and 9 by adding IM of a hydrochloric acid solution.

[0140] Advantageously, the droplet of mixture is immersed in the crosslinking bath for 5 to 20 min, preferably for 5 to 10 min, such as for 5 to 6 min to form the microsphere according to the invention. The immersion time of the droplet of mixture in the crosslinking bath makes it possible, in particular, to control the degree of crosslinking of the microsphere formed. Preferably, the crosslinking of the mixture in the microsphere is complete, that is to say, the diffusion of the divalent cations has occurred to the core of the microsphere, creating a three-dimensional structure throughout the entire volume of the microsphere (crosslinking throughout the core and not only on the surface).

[0141] At the end of the crosslinking, the microsphere formed in the crosslinking bath is recovered.

[0142] Once the microsphere has been recovered, it can be rinsed with water. This rinsing helps to stop the cross-linking of the microsphere.

[0143] The recovered or rinsed microsphere can be drained and / or dried. Preferably, the microsphere is dried using any technique well known to those skilled in the art, such as an air-flow technique.

[0144] The microsphere can then be conditioned (bagged, for example) and preferably stored at ambient temperature and humidity, protected from light.

[0145] Advantageously, the microsphere comprises: - 5 to 30% by mass of water, - 2 to 30% by mass of an alkaline earth metal peroxide, - 7 to 30% by mass of aerobic alkalophilic or alo-tolerant saprophytic microorganisms, - 35 to 80% by mass of nutrient(s) for microorganisms, - 0.02 to 3% by mass of a base, - 0.5 to 6% by mass of a divalent alginate salt, the mass percentages being given on the mass of the microsphere.

[0146] Preferably, the microsphere comprises: - 10 to 25% by mass of water, - 5 to 25% by mass of an alkaline earth metal peroxide, - 15 to 25% by mass of aerobic, alkalophilic or alo-tolerant saprophytic microorganisms, - 40 to 68% by mass of nutrient(s) for microorganisms, - from 0.05 to 2% by mass of a base, - 1 to 5% by mass of a divalent alginate salt, the mass percentages being given on the mass of the microsphere.

[0147] According to another aspect, the invention also relates to the use of the composition in powder form, solution, mixture or microsphere in the depollution of an environment.

[0148] More specifically, the decontamination is carried out by biochemical remediation.

[0149] Environmental depollution is carried out by bringing the composition in powder form, the solution, the mixture or the microsphere into contact with the environment to be depolluted.

[0150] When the depollution is carried out with the composition in powder form, it can be brought into contact with the environment to be depolluted by spreading as indicated previously.

[0151] When the pollution control is carried out with the solution or mixture, these can be brought into contact with the environment to be decontaminated by watering, spraying, spreading.

[0152] When the pollution control is carried out with the microsphere, the latter can be brought into contact with the environment to be decontaminated by spreading, dispersion, or alternatively by spraying or injection under pressure after being suspended in a liquid.

[0153] Preferably, the environment to be decontaminated is chosen from the group consisting of wastewater and / or soils.

[0154] Other advantages, purposes and particular features of the present invention will become apparent from the following non-limiting description of at least one particular embodiment of the devices and methods of the present invention, with reference to the accompanying drawings, in which: - [Fig.l] represents the release of dioxygen from the microspheres according to the invention and of CaO2 (reference) over time for 8 minutes; - [Fig.2] represents the release of dioxygen from the microspheres according to the invention and of CaO2 (reference) over time for (90 hours) 4 days.

[0155] Example 1: Preparation of the composition according to the invention

[0156] Material: - Glassware: beakers of all sizes - Product: demineralized water, sodium hydroxide (solid NaOH), calcium peroxide (powder, Sigma and IXPER), Fe2+ - Other: spatulas - Standard culture medium: Soy or casein peptone, dextrose - Fungal strain: The fungal strain is selected for its alkalophilic properties, for example, Fusarium Solani, in culture on agar.

[0157] Method:

[0158] Step 1: Preparation of the fungal culture in liquid medium (fungal culture medium)

[0159] For 1.5 L of medium, 30 g of dextrose and 22.5 g of peptone were used, and the solution was made up with demineralized water. The pH was adjusted to 7, if necessary. The culture medium was autoclaved at 121°C for 20 minutes. The culture medium was left to cool overnight under a laminar flow hood. Once the culture medium had cooled to room temperature, it was inoculated with the fungal strain culture on agar under an axenic environment and placed on a magnetic stirrer for 5 days. The stopper was fitted with a 0.2 µm air filter. The fungal culture medium was then ground for 30 s, and the pH was adjusted to 7, if necessary.

[0160] Step 2: Preparation of the composition

[0161] For 500 mL of composition: in a 1 L beaker, 237.5 g of demineralized water and 237.5 g of fungal culture medium were added, then mixed with a spatula and 25 g of CaO2 were added by mixing for 1-2 minutes with a mixer and optionally 0.2 g of sodium hydroxide can be weighed and added to the composition.

[0162] It is also possible to add an iron salt (such as, for example, a ferrous salt or a ferric salt) to the composition in step 2.

[0163] The iron salt can be chosen from iron sulfate, iron (II) oxide or ferrous oxide FeO, iron (III) oxide or ferric oxide Fe2O3, hydrated ferric oxide (Fe2 O3.H2O) or mixtures thereof.

[0164] As an example of a mixture of salts, which can be found in the form of ores, we can cite "magnetite" (Fe3O4), hematite (Fe2O3), or limonite (Fe2O3.xH2O).

[0165] The composition according to the invention thus obtained can then be dried and / or ground to obtain a powder.

[0166] Example 2: Preparation of a mixture and microspheres according to the invention

[0167] Materials: - Glassware: beakers of all sizes - Product: demineralized water, sodium hydroxide (solid NaOH), humic acid, high-viscosity sodium alginate, phytic acid (inositol hexaphosphate), calcium peroxide (powder, Sigma and IXPER), hydrochloric acid (CaCl2) - Other items: syringe, spatulas - Standard culture medium: Soy peptone, dextrose - Fungal strain: The fungal strain is selected for its alkalophilic properties, for example, Coprinus comatus, in culture on agar.

[0168] Method:

[0169] Step 1: Preparation of the fungal culture in liquid medium

[0170] The fungal culture was prepared as in Example 1, step 1.

[0171] Step 2: Preparation of the mixture according to the invention

[0172] For 500 mL of mixture: in a 1 L beaker, 0.2 g of sodium hydroxide and 10 g of humic acid were weighed out, 229 g of demineralized water and 229 g of fungal culture medium were added and then mixed with a spatula. 5 g of high-viscosity sodium alginate were added and mixed with a mixer for 5 minutes, taking care to break up any lumps, 1.85 g of phytic acid diluted to 50% in water were added and mixed, then 25 g of CaO2 were added, mixing for 1-2 minutes with a mixer.

[0173] Step 3: Fabrication of the microspheres according to the invention

[0174] The mixture was transferred to the encapsulator by a diaphragm pump.

[0175] A microfiltered air compressor supplies the device and the process parameters have been adjusted to: - A 1mm nozzle was used. - Frequencies used: 80Hz - 240Hz - Nominal pressure: 1500-3200 mbar

[0176] A crosslinking bath was prepared such that: - Water (running) - CaCl2: between 0.1M and IM

[0177] For a bath with a volume equivalent to the volume to be encapsulated, the concentration is 0.1M of CaCl2. And for a bath equivalent to 4x the volume to be encapsulated, the concentration is 1M of CaCl2.

[0178] The bath was extended between 5 and 10 minutes. The bath was agitated by recirculating the fluid. The pH of the bath was monitored with a probe. A few drops of IM hydrochloric acid solution were added regularly to limit the pH increase to between 7 and 9.

[0179] The microspheres were removed from the bath and rinsed with ultrapure water. The microspheres were drained and dried under a fume hood or dehydrator.

[0180] Example 3: Release of dioxygen by reference microspheres containing CaO2 (hereinafter referred to as "CaO2 reference microspheres")

[0181] The release of dioxygen over time by reference microspheres containing CaO2 (without microorganisms) was measured, and the efficiency of this release was deduced. The objective of this measurement is to determine the quantity of dioxygen released by the CaO2 reference microspheres in order to ensure its availability for any microorganisms that might be added to the microspheres and whose growth would depend on this availability.

[0182] 1. Preparation of microspheres

[0183] Materials: - Glassware: beakers of all sizes - Product: demineralized water, sodium hydroxide (solid NaOH), humic acid, high viscosity sodium alginate, phytic acid (inositol hexaphosphate), calcium peroxide (powder, Sigma and IXPER), CaCl2, hydrochloric acid, - Other items: syringe, spatulas

[0184] Method:

[0185] Step 1: Preparing the mixture

[0186] For 500 mL of mixture: In a 1 L beaker, 0.2 g of sodium hydroxide and 10 g of humic acid were weighed out, 458 g of demineralized water were added, and then mixed with a spatula. 5 g of high-viscosity sodium alginate were added and mixed with a mixer for 5 minutes, taking care to break up any lumps. 1.85 g of phytic acid diluted to 50% in water were added and mixed, and then 25 g of CaO2 were added, mixing for 1-2 minutes with a mixer. The resulting mixture has a pH greater than 11.

[0187] Step 2: Fabrication of CaO2 reference microspheres

[0188] The CaO2 reference microspheres were prepared as in Example 2, step 3.

[0189] 2. Oxygen release and efficiency of oxygen release by the reference CaO2 microspheres over time

[0190] The release of dioxygen by reference CaO2 microspheres was measured and the efficiency of dioxygen release by these reference CaO2 microspheres could be deduced.

[0191] The amount of dioxygen exiting the CaO2 reference microspheres was measured using an O2 probe placed in sealed 100 mL flasks. 0.4% of CaO2 reference microspheres were weighed per 100 mL of demineralized water previously degassed with nitrogen. The CaO2 reference microspheres were then were quickly introduced into the bottles. The bottles were left under agitation at room temperature (the probe takes the temperature into account).

[0192] The negative control "water" corresponds to a sealed vial without the addition of microspheres, with 100 mL of demineralized and degassed water, which was opened for a few seconds to simulate the time of addition of the microspheres.

[0193] The positive control “CaO2” corresponds to a sealed bottle into which 0.2% of CaO2 has been introduced for 100mL of demineralized water previously degassed with nitrogen.

[0194] There is about 50% CaO2 in the microspheres, therefore twice as many microspheres were added as pure CaO2 powder in order to compare their release.

[0195] The oxygen release results are shown in [Fig. 1] and [Fig. 2]. The figures represent the quantities of oxygen released in demineralized and degassed water for different samples: CaO2, which serves as a positive control; demineralized and degassed water, which serves as a negative control; and CaO2 reference microspheres.

[0196] Fig. 1 represents the release of dioxygen over 8 minutes and Fig. 2 represents the release of dioxygen over 90 hours (4 days).

[0197] The results in [Fig. 1] show that the CaO2 reference microspheres produce an oxygen release. This release is less significant than that of pure CaO2 powder (CaO2, positive control). It is also not due to opening the bottle when adding the CaO2 reference microspheres, as the negative control (water only) indicates O2 concentration values ​​close to 0 mg / L.

[0198] The results in [Fig. 2] show that the CaO2 reference microspheres produce oxygen release, and that this oxygen release is greater at the beginning of the monitoring period than at the end. Furthermore, the oxygen release efficiency of the CaO2 reference microspheres is 68% at 3 days and 74% at 4 days. The oxygen release efficiency was measured using the following formula:

[0199] Cipicrospheres - , in which C represents the concentration. aOl^CaOl -C(O2)emi 1

[0200] In conclusion, the CaO2 reference microspheres allow the release of dioxygen over time. This dioxygen will then be used by microorganisms to facilitate their growth in a microaerobic and constrained environment. Example 4#: Release of H2O2#

[0201] The release of hydrogen peroxide (H2O2) over time was measured, and its release efficiency was deduced. This measurement will allow us to determine the quantity of hydrogen peroxide (H2O2) released by the Microspheres. The purpose of this hydrogen peroxide (H2O2) release is to subsequently be used, directly or indirectly, for the biodegradation of polluting organic compounds. This hydrogen peroxide release results from the lowering of the pH by microorganisms present in the microspheres, which promotes the dissociation of the hydrogen peroxide.

[0202] 1. Preparation of microspheres

[0203] Materials: - Glassware: beakers of all sizes - Product: demineralized water, soda (solid NaOH), humic acid, high viscosity sodium alginate, phytic acid (inositol hexaphosphate), calcium peroxide (powder, Sigma and IXPER), CaCl2>, hydrochloric acid, talc; - Other items: syringe, spatulas - Standard culture medium: Soy peptone, dextrose - Fungal strain: The fungal strain is selected for its alkalophilic properties, for example, Aspergillus flavus, in culture on agar.

[0204] Method: 1. Microspheres according to the invention: the microspheres are prepared according to the method described in example 2. 2. Reference microspheres containing CaO2 alone: ​​the microspheres are prepared according to the method described in example 3. 3. Reference microspheres containing the fungal strain:

[0205] Step 1: Preparation of the fungal culture in liquid medium

[0206] The fungal culture was prepared as in Example 1, step 1.

[0207] Step 2: Preparing the mixture

[0208] For 500 mL of mixture: in a 1 L beaker, 0.2 g of sodium hydroxide and 10 g of humic acid were weighed out, 229 g of demineralized water and 229 g of fungal culture medium were added and then mixed with a spatula. 5 g of high-viscosity sodium alginate were added and mixed with a mixer for 5 minutes, taking care to break up any lumps, 1.85 g of phytic acid diluted to 50% in water were added and mixed, then 25 g of CaO2 were added, mixing for 1-2 minutes with a mixer.

[0209] Step 3: Production of microspheres containing the fungal strain

[0210] The microspheres containing the fungal strain were prepared as in Example 2, step 3.

[0211] 2. Production of hydrogen peroxide

[0212] Four flasks containing 100 mL of demineralized water were prepared. Then, the Microspheres were poured according to the following conditions: - 200 mg of microspheres according to the invention to be tested - 142 mg of Reference CaO2 microspheres - 200 mg of reference fungal strain microspheres

[0213] All the bottles were shaken.

[0214] The production of H2O2 was monitored every minute for 10 minutes using strips designed to detect the presence of hydrogen peroxide in solution. Then, the values ​​were taken hourly for 1 day and then once a day for 3 days.

Claims

Demands

1. Composition in powder form comprising: - 1 to 50% by mass of an alkali-earth metal peroxide, - 0.5 to 50% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, - 10 to 90% by mass of nutrient ingredient(s) for microorganisms, - 0 to 2% by mass of a base, - the percentages by mass being given on the mass of the composition in powder form.

2. A powder composition according to claim 1, wherein the aerobic alkalophilic or alkalotolerant saprophytic microorganisms are fungi, said fungi being of genera selected from the group consisting of Acremonium, Aspergillus, Fusarium, Coprinus, Penicillium, Pleurotus, Trichoderma, Gliocladium, Phialophora, Stachylidium, Stilhella and their mixtures.

3. Composition in powder form according to claim 1 or 2, comprising an iron salt.

4. A method for preparing a powder composition according to any one of claims 1 to 3, by mixing alkaline earth metal peroxide, aerobic alkalophilic or alkalotolerant saprophytic microorganisms, nutrient ingredient(s) and optionally base.

5. Solution comprising the composition in powder form according to any one of claims 1 to 3, and water.

6. Solution comprising: - 50 to 95% by mass of water, - 2 to 10% by mass of an alkaline earth metal peroxide, - 1 to 20% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, - 1 to 30% by mass of nutrient ingredient(s) for microorganisms, - 0 to 0.2% by mass of a base, the percentages by mass being given on the mass of the solution.

7. Mixture comprising the solution according to claim 5 or 6, and a monovalent alginate salt.

8. Microsphere comprising: - 3 to 50% by mass of water, - 0.5 to 40% by mass of an alkali-earth metal peroxide, - 2 to 35% by mass of aerobic alkalophilic or alkalotolerant saprophytic microorganisms, - 30 to 90% by mass of nutrient ingredient(s) for microorganisms, - 0.01 to 5% by mass of a base, - 0.1 to 7% by mass of a divalent alginate salt, the percentages by mass being given on the mass of the microsphere.

9. Microsphere capable of being obtained by crosslinking the mixture according to claim 7, in the presence of a divalent salt.

10. A method for obtaining a microsphere according to claim 8 or 9, comprising a crosslinking step of the monovalent alginate salt contained in a drop of a mixture according to claim 7.

11. Use of the composition in powder form according to any one of claims 1 to 3, of the solution according to claims 5 or 6, of the mixture according to claim 7 or of the microsphere according to claim 8 or 9, in the decontamination of an environment.

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