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

Abstract

The invention relates to a composition in powder form, comprising an alkaline earth metal peroxide, alkalophilic or alkalotolerant aerobic saprophytic microorganisms, nutritive ingredients for these microorganisms, and optionally a base; and a solution as well as microspheres, their preparation processes and their uses in the decontamination of environments such as soils and aqueous media. figure for 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 decontamination of environments such as soils and aqueous media.

[0002] Pollution caused by industrial activities, agricultural activities, massive exploitation of hydrocarbons and other human activities represent risks for marine and terrestrial ecosystems as well as for human health. Thus, 75% of terrestrial soils are polluted. This soil pollution is not insignificant and causes an alteration of soil biodiversity, a reduction of organic matter and the capacity of soils to act as a filter, which leads to the contamination of water stored in soils and groundwater. Therefore, the decontamination of soils and aqueous environments represents a crucial issue.

[0003] To date, solutions are being implemented to combat pollution of soils and aqueous environments, upstream, but also downstream, for the decontamination of these environments, whether by off-site, on-site or in-situ decontamination methods. The decontamination methods can be diverse, such as biological decontamination, which includes decontamination by biochemical remediation, or physicochemical decontamination, which includes different extraction techniques (by suction, electrical, by heating, etc.) or decontamination by soil replacement.

[0004] Biochemical remediation is one of the alternatives used for the decontamination of an environment such as soil or an aqueous medium. Biochemical remediation consists of the decontamination of these environments thanks in particular to microorganisms capable of degrading complex molecules.

[0005] However, decontamination by biochemical remediation has intrinsic limits, particularly in 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. However, this bioavailability is limited and is difficult to control over time. In addition, biochemical remediation requires the prior and voluntary modification of the chemical reaction parameters by the operator, over time, such as pH and temperature, which will depend on the quantity of polluting products present in the environment to be decontaminated. As a result, all these drawbacks induce limited technical results in terms of environmental decontamination and a significant financial cost.

[0006] The work of the inventors has made it possible to demonstrate that it was possible to develop a composition allowing the development of micro-organisms in order to allow the oxidation of polluting compounds present in soils and aqueous environments as well as the progressive and controlled release of elements necessary for their activities and in particular hydrogen peroxide. Indeed, the release of hydrogen peroxide will participate directly or indirectly in the biodegradation of polluting organic compounds. In addition, the development of micro-organisms will allow, via its metabolism, biodegradation by means of the metabolites and enzymes that they are likely to secrete.

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

[0008] In the present application, unless otherwise specified, all numerical values ​​given are understood to be inclusive.

[0009] By "in powder form" is meant 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 μm.

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

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

[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 their mixtures, 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 composition in powder form.

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

[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 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 archaeobacterium, a virus, a protist, a plant (such as an algae), an animal (such as a protozoan) or a fungus.

[0020] By "saprophyte" is meant a plant, animal, fungal or bacterial organism capable of feeding on decomposing organic matter.

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

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

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

[0024] By "micro-tolerant" is meant a microorganism that can grow in environments with a basic pH, that is, in environments with 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 particularly, 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, multicopper 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 deslaccases.

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

[0031] Preferably, the composition in powder form in which the alkalophilic or alkalotolerant aerobic saprophytic microorganisms are fungi, said fungi being of genus(es) chosen from the group consisting of Acremonium, Aspergillus, Fusarium, Coprinus, Penicillium, Pleurotus, Trichoderma, Gliocladium, Phialophora, Stachylidium, Stilhellacl and mixtures thereof.

[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 alkalophilic or alkalotolerant aerobic 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 alkalophilic or alkalotolerant aerobic 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(s) as indicated above or other fungi. By "other fungi" is meant at least one fungus of a species which is not aerobic, alkalophilic or alkalotolerant saprophytic.

[0036] As an example of other fungi, mention may be made of fungi capable of producing 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 consortium of fungi comprises 2 species of fungi, preferably 3 species of fungi. The consortium of fungi 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 consortium of fungi may be composed of the species Coprinus comatus, Trametes versicolor and Lactarius laccata.

[0045] Alternatively, the fungal consortium may be composed 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 and 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 composition in powder form comprises between 10 and 90% by mass of nutritive ingredient(s), expressed on the total mass of composition in powder form.

[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 composition in powder form.

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

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

[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 composition in powder form.

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

[0055] By “base” is meant 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 soda, potassium hydroxide (KOH), also called potash or their mixtures. 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 composition in powder form.

[0058] The addition of a base to the composition in powder form will make it possible to stabilize said composition.

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

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

[0061] Indeed, if the environment to be decontaminated is an aqueous medium, for example of the wastewater type, the composition in powder form can be spread directly into this environment. Alternatively, if the environment to be decontaminated is a non-aqueous medium, for example soil, the composition in powder form can be spread directly into this environment. However, an addition of water into 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 the organic pollutants present in the environment to be depolluted.

[0063] Without wishing to be bound by any theory, the applicant believes that initially, at basic pH, the progressive and controlled release of dioxygen will to ensure the initial growth of the microorganism, via the dissociation, upon contact with water, of the alkaline earth metal peroxide. Thus, the microorganisms present in the composition will grow and through their metabolism promote the release of metabolites and enzymes allowing the oxidation of polluting compounds. This secretion of metabolites will also induce a progressive lowering of the 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] Decontamination by hydrogen peroxide can be done in three ways, by direct contact, by chemical catalysis and by biological catalysis.

[0065] Direct contact decontamination is carried out by redox reaction between a donor and an acceptor of electron(s), i.e. between an oxidant (reduced) and a reducer (oxidized). Direct contact decontamination is dependent on the oxidizing and reducing potential of the hydrogen peroxide and the pollutant and, therefore, on the environment to be decontaminated.

[0066] Chemical catalysis decontamination is carried out by reacting a metal such as iron with hydrogen peroxide to produce OH radicals. Since these OH radicals are unstable, they will oxidize the organic and inorganic compounds in the environment to be decontaminated.

[0067] Decontamination by biological catalysis, for its part, 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 decontaminated.

[0068] As a result, hydrogen peroxide will be able to degrade by oxidation environmental pollutants, such as total petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins and furans. This degradation by oxidation can be complete and produce CO2 and water or incomplete and produce 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, i.e. at a pH below 7, the dissociation of alkaline earth metal peroxide (CaO2) into hydrogen peroxide (H2O2) is favored compared to dioxygen (O2). Conversely, at a basic pH, i.e. at a pH above 7, the dissociation of alkaline earth metal peroxide (CaO2) into dioxygen (O2) is favored compared to hydrogen peroxide (H2O2).

[0070] The composition in powder form comprises for example: - from 5 to 40% by mass of an alkaline earth metal peroxide, preferably CaO2 - from 0.5 to 40% by mass of alkalophilic or alkali-tolerant aerobic saprophytic microorganisms, - from 20 to 85% by mass of nutritive ingredient(s) for microorganisms, - optionally from 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 composition in powder form according to the invention comprises: - from 10 to 30% by mass of an alkaline earth metal peroxide, preferably CaO2, - from 1 to 40% by mass of alkalophilic or alo-tolerant aerobic saprophytic microorganisms, - from 30 to 80% by mass of nutritive ingredient(s) for microorganisms, - optionally from 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 composition in powder form according to the invention comprises: - from 12 to 25% by mass of CaO2, - from 1 to 30% by mass of alkalophilic or alo-tolerant aerobic saprophytic microorganisms, - from 40 to 70% by mass of nutritive ingredient(s) for microorganisms, - optionally from 0.10 to 0.40% by mass of soda, the mass percentages being given on the mass of the compositions in powder form.

[0073] Advantageously, the composition in powder form 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 decontamination, 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” is meant an iron salt comprising a divalent iron, i.e. having an oxidation state of +11.

[0077] By “ferric salt” is meant an iron salt comprising a trivalent iron, i.e. 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 association 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 composition in powder form 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 composition in powder form.

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

[0082] According to a first embodiment of the method for preparing the composition, the alkaline earth metal peroxide, the alkalophilic or alkalotolerant aerobic saprophytic microorganisms, the nutritive 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 method for preparing the composition, a first mixing step is carried out in the presence of water. For example, a fungal culture in a liquid medium can be prepared, comprising water, alkalophilic or alkalotolerant aerobic saprophytic microorganisms and the nutritive ingredient(s). A second mixing step then allows the addition of the alkaline earth metal peroxide and optionally the base, thus making it possible to obtain a solution. Finally, a step of drying and / or grinding the solution then makes it possible to obtain the composition in powder form.

[0084] Said methods may further comprise a step of incorporating iron salt.

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

[0086] By "water" is meant tap water, mineral water, ultra-pure water or demineralized water. Preferably, the water is demineralized water.

[0087] More particularly, the solution comprises: - from 50 to 95% by mass of water, - from 2 to 10% by mass of an alkaline earth metal peroxide, - from 1 to 20% by mass of alkalophilic or ale alo tolerant aerobic saprophytic microorganisms, - from 1 to 30% by mass of nutrient ingredient(s) for the microorganisms, - from 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, except for the contents, the alkaline earth metal peroxide, the alkalophilic or alkalotolerant aerobic saprophytic microorganisms, the nutrient ingredient(s) and the optional base are as described above, including the 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 alkalophilic or alkalotolerant aerobic saprophytic microorganisms, preferably between 3 and 12% by mass of alkalophilic or alkalotolerant aerobic saprophytic microorganisms, more preferably between 4 and 10% by mass of alkalophilic or alkalotolerant aerobic saprophytic microorganisms, expressed on the total mass of the solution.

[0092] Advantageously, the solution comprises between 5 and 25% by mass of nutritive ingredient(s), preferably between 10 and 20% by mass of nutritive ingredient(s), more preferably between 12 and 18% by mass of nutritive 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 particularly, 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, even more preferably between 0.04 and 0.05% by mass of a base, expressed on the total mass of the solution. The addition of sodium hydroxide to the solution can in particular make it possible to avoid the early initiation of the reaction of the dissociation of CaO2 into dioxygen.

[0095] The solution may also comprise an iron salt, as defined above.

[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 process for preparing the solution, by mixing water, alkaline earth metal peroxide, aerobic alkalophilic alkalotolerant saprophytic microorganisms, nutritive ingredient(s) and optionally the base.

[0098] According to a first embodiment of the method for preparing the solution, the latter may comprise a step of providing the composition in powder form as defined previously, 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 method for preparing the solution, certain ingredients of the composition in powder form may be premixed with water during a first mixing step. For example, the nutrient ingredient(s) may be mixed with water to form a culture medium. The alkalophilic or alkalotolerant aerobic saprophytic microorganisms may then be added to form a fungal culture in a liquid medium. Finally, during a second mixing step, the alkaline earth metal peroxide and optionally the base may be added to form the solution.

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

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

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

[0104] By "monovalent alginate salt" is meant a salt of deprotonated alginic acid. Alginic acid and its derivatives such as alginates are polysaccharides that originate 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. The sodium alginate may be chosen from the group consisting of high viscosity sodium alginate (viscosity at 25°C, at 1% (m / v), greater than 3500 mPa.s), medium viscosity sodium alginate (viscosity at 25°C, at 1% (m / v), between 240-3500 mPa.s) and low viscosity sodium alginate (viscosity at 25°C, at 1% (m / v), less than 240 mPa.s).

[0108] Preferably, the 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 chelator 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 chelator is phytic acid.

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

[0114] Advantageously, the mixture may also comprise humic acid. The mixture may comprise 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 the total mass of the mixture.

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

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

[0117] The invention also relates to a microsphere comprising: - from 3 to 50% by mass of water, - from 0.5 to 40% by mass of an alkaline earth metal peroxide, - from 2 to 35% by mass of alkalophilic or alo-tolerant aerobic saprophytic microorganisms, - from 30 to 90% by mass of nutritive ingredient(s) for microorganisms, - from 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, except for the contents, the water, the alkaline earth metal peroxide, the alkalophilic or alkalotolerant aerobic saprophytic microorganisms, the nutritive ingredient(s) and the base are as described above, including the preferred and advantageous modes.

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

[0120] Due to 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] By "divalent alginate salt", we preferably mean 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 alkalophilic or alkalotolerant aerobic saprophytic microorganisms, preferably between 7 and 30% by mass of alkalophilic or alkalotolerant aerobic saprophytic microorganisms, more preferably between 15 and 25% by mass of alkalophilic or alkalotolerant aerobic 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 salt of alginate, expressed on the total mass of the microsphere.

[0128] The microsphere according to the invention may further comprise a chelator as defined above and / or humic acid. The humic acid makes it possible in particular to perfect the aesthetic appearance of the microsphere.

[0129] The microsphere will allow the decontamination of the environment. The water present in the environment to be decontaminated will be inserted by capillarity into the microsphere and allow the initiation of the dissociation of the alkaline earth metal peroxide into dioxygen, said dioxygen then allowing the development of microorganisms. The base present in the microsphere advantageously allows the pH of the latter to be maintained between 9 and 12, in contact with water, which makes it possible to promote the dissociation of the alkaline earth metal peroxide into dioxygen. This will allow alkalophilic or alkalotolerant aerobic saprophytic microorganisms to develop in the presence of the dioxygen thus released.

[0130] The microsphere is capable of being 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 comprise a base. Indeed, without wishing to be bound by any theory, it is considered that when obtaining the microspheres by crosslinking the mixture, the base present in the mixture will advantageously make it possible to prevent interactions between the alkaline earth metal of the alkaline earth metal peroxide and the monovalent alginate salt, an undesired early crosslinking of the monovalent alginate salt being likely to result from these interactions. Indeed, 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 make it possible to react with the released alkaline earth metal, to form a metal hydroxide, and avoid crosslinking.

[0133] The invention also relates to a process for obtaining a microsphere comprising a step of crosslinking 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 makes it possible to crosslink 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 of 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 of the mixture can be carried out by a pump. For example, the drip can be carried out by a membrane pump.

[0138] Advantageously, the crosslinking bath is stirred.

[0139] Advantageously, the pH of the crosslinking bath is between 7 and 9. For example, the pH of the crosslinking bath can be maintained between 7 and 9 by adding 1M of a hydrochloric acid solution.

[0140] Advantageously, the drop 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 drop 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 that the diffusion of the divalent cations has taken place up to the core of the microsphere, creating a three-dimensional structure in the entire volume of the microsphere (crosslinking at the core and not only at 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 makes it possible in particular to stop the crosslinking 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 airflow technique.

[0144] The microsphere can then be packaged (bagged, for example) and preferably stored at room temperature and humidity away from light.

[0145] Advantageously, the microsphere comprises: - from 5 to 30% by mass of water, - from 2 to 30% by mass of an alkaline earth metal peroxide, - from 7 to 30% by mass of alkalophilic or alkali tolerant aerobic saprophytic microorganisms, - from 35 to 80% by mass of nutritive ingredient(s) for the microorganisms, - from 0.02 to 3% by mass of a base, - from 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: - from 10 to 25% by mass of water, - from 5 to 25% by mass of an alkaline earth metal peroxide, - 15 to 25% by mass of alkalophilic or alkali-tolerant aerobic saprophytic microorganisms, - from 40 to 68% by mass of nutritive ingredient(s) for microorganisms, - from 0.05 to 2% by mass of a base, - from 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, of the solution, of the mixture or of the microsphere in the decontamination of an environment.

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

[0149] The decontamination of an environment is carried out by bringing the composition in the form of powder, solution, mixture or microsphere into contact with the environment to be decontaminated.

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

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

[0152] When the decontamination is carried out with the microsphere, it can be brought into contact with the environment to be decontaminated by spreading, dispersion, or alternatively by sprinkling or injection under pressure after suspension in a liquid.

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

[0154] Other advantages, aims and particular characteristics of the present invention will emerge from the following non-limiting description of at least one particular embodiment of the devices and methods which are the subject of the present invention, with reference to the appended drawings, in which: - [Fig.l] represents the release of dioxygen from the microspheres according to the invention and CaO2 (reference) over time for 8 minutes; - [Fig.2] represents the release of dioxygen from the microspheres according to the invention and 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, soda (solid NaOH), calcium peroxide (powder, Sigma and IXPER), Fe2+ - Others: 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 1.5L of medium, 30g of dextrose and 22.5g of peptone were used, and supplemented with demineralized water. The pH was adjusted to pH 7, if necessary. The culture medium was autoclaved at 121°C for 20 minutes. The culture medium was left to cool under a laminar flow hood overnight. Once the culture medium had cooled to room temperature, it was inoculated from the agar culture comprising the fungal strain, under an axenic environment, and was placed on a magnetic stirrer for 5 days. The cap 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 pH 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 soda 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 during step 2.

[0163] The iron salt may 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, soda (solid NaOH), humic acid, high viscosity sodium alginate, phytic acid (inositol hexaphosphate), calcium peroxide (powder, Sigma and IXPER), CaCl2 hydrochloric acid - Others: 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, 229 g of demineralized water and 229 g of fungal culture medium were added, then mixed with a spatula. 5 g of high-viscosity sodium alginate were added and mixed in a mixer for 5 minutes, taking care to break up the 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 in a mixer.

[0173] Step 3: Production 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 were 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 1M

[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 evolution of the pH of the bath was monitored with a probe. A few drops of a 1M hydrochloric acid solution were added regularly to limit the increase in pH 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 hood or dehydrator.

[0180] Example 3: Release of dioxygen by reference microspheres comprising CaO 2 (hereinafter referred to as “CaO 2 reference microspheres”)

[0181] The release of oxygen, over time, by reference microspheres comprising CaO2 (without microorganisms) was measured and the release efficiency of the latter could be deduced therefrom. The objective of this measurement is to determine the quantity of oxygen released by the CaO2 reference microspheres, in order to ensure its availability, for possible microorganisms which could 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, soda (solid NaOH), humic acid, high viscosity sodium alginate, phytic acid (inositol hexaphosphate), calcium peroxide (powder, Sigma and IXPER), CaCl2, hydrochloric acid, - Others: syringe, spatulas

[0184] Method:

[0185] Step 1: Preparation of 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, 458 g of demineralized water were added, then mixed with a spatula. 5 g of high-viscosity sodium alginate were added and mixed in a mixer for 5 minutes, taking care to break up the lumps, 1.85 g of phytic acid diluted 50% in water were added and mixed, then 25 g of CaO2 were added, mixing for 1-2 minutes in a mixer. The mixture thus obtained has a pH greater than 11.

[0187] Step 2: Production of the CaO2 reference microspheres

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

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

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

[0191] The amount of oxygen leaving 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 quickly introduced into the flasks. The flasks were left stirring at room temperature (the probe takes the T°C into account).

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

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

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

[0195] The oxygen release results are shown in [Fig.l] and [Fig.2]. The figures represent the amounts of oxygen released into 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 the CaO2 reference microspheres.

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

[0197] The results in [Fig.l] show that the CaO2 reference microspheres produce a release of dioxygen. This release is less significant than the pure CaO2 powder (CaO2, positive control). It is also not due to the opening of the bottle when adding the CaO2 reference microspheres because the negative control (water alone) 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 the oxygen release is greater at the beginning of the monitoring than at the end. In addition, 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 with the following formula:

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

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

[0201] The release of hydrogen peroxide (H2O2) over time was measured and the efficiency of its release could be deduced. This measurement will make it possible to determine the quantity of hydrogen peroxide (H2O2) released by the microspheres. The purpose of this release of hydrogen peroxide (H2O2) is to be subsequently used directly or indirectly for the biodegradation of polluting organic compounds. This release of hydrogen peroxide results from the lowering of the pH by the microorganisms present in the microspheres, which will promote the dissociation of 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; - Others: 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: Preparation of 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, 229 g of demineralized water and 229 g of fungal culture medium were added, then mixed with a spatula. 5 g of high-viscosity sodium alginate were added and mixed in a mixer for 5 minutes, taking care to break up the 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 in a mixer.

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

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

[0211] 2. Production of hydrogen peroxide

[0212] 4 bottles containing 100 mL of demineralized water were prepared. Then, the microspheres were poured under the following conditions: - 200 mg of microspheres according to the invention to be tested - 142 mg of CaO2 Reference microspheres - 200 mg of fungal strain reference microspheres

[0213] All the bottles were shaken.

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

Claims

Claims

1. Composition in powder form comprising: - from 1 to 50% by mass of an alkaline earth metal peroxide, - from 0.5 to 50% by mass of alkalophilic or alkalotolerant aerobic saprophytic microorganisms, - from 10 to 90% by mass of nutritive ingredient(s) for the microorganisms, - from 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 composition in powder form according to claim 1, wherein the alkalophilic or alkalotolerant aerobic saprophytic microorganisms are fungi, said fungi being of genus(es) chosen from the group consisting of Acremonium, Aspergillus, Fusarium, Coprinus, Penicillium, Pleurotus, Trichoderma, Gliocladium, Phialophora, Stachylidium, Stilhellacl and mixtures thereof.

3. A powder composition according to claim 1 or 2, comprising an iron salt.

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

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

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

7. A mixture comprising the solution of claim 5 or 6, and a monovalent alginate salt.

8. Microsphere comprising: - from 3 to 50% by mass of water, - from 0.5 to 40% by mass of an alkaline earth metal peroxide, - from 2 to 35% by mass of alkalophilic or alkalotolerant aerobic saprophytic microorganisms, - from 30 to 90% by mass of nutritive ingredient(s) for the microorganisms, - from 0.01 to 5% by mass of a base, - from 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 obtainable by crosslinking the mixture according to claim 7, in the presence of a divalent salt.

10. A method of obtaining a microsphere according to claim 8 or 9, comprising a step of crosslinking 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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