BE1023862B1 - AIRBORNE AND RESISTANT CONSTANTS OF FILAMENTOUS FUNGUS STRAINS AND PROCESS FOR OBTAINING THEM - Google Patents

Abstract

The present invention relates to a process for obtaining conidia or spores of strains of filamentous fungi, conidia or spores obtained and their agronomic and agro-food applications.

Description

Aerial and resistant conidia of strains of filamentous fungi and their method of obtaining

OBJECT OF THE INVENTION [0001] The present invention relates to the field of biological control, or bio-control, of pests of crops, and relates in particular to conidia or spores, aerial and resistant, of strains of fungi filamentous, in particular conidia or spores of Pseudozyma Trichoderma or Penicillium in powder form, and their method of production and their applications, as biological control agent or agrifood.

BACKGROUND OF THE INVENTION [0002] Biological control, also called bio-control, is a known method for the protection of plants against, for example, pests, crop pests, such as insects, mites or mites. nematodes, protection or treatment against diseases, in particular fungal, bacterial or viral diseases, or a method of controlling weeds, weeds, by the use of either living antagonistic organisms or biodegradable products constituents of these organisms, or of metabolites produced by these organisms, called biological control agents.

As this fight involves living organisms, such as predators such as nematodes, arthropods, vertebrates, or molluscs, or pathogens, such as bacteria or fungi, or natural herbivorous substances, or phytophages, or to constituents or metabolites produced by these living organisms, it has the advantage of being made without the use of chemical pesticides.

Indeed, with all the problems caused by chemical pesticides on the environment, there is a growing interest in exploiting new biological materials, or new living organisms, such as for example filamentous fungi, or their metabolites. primary or secondary, for the control of pests, weeds and / or diseases.

In addition, it should be noted that, particularly with regard to fungal biological control, the latter is articulated around multiple disciplines, such as the pathology of the strain used, ecology, physiology, mass production, formulation and application strategies.

There are a large number of strains of fungi, in particular filamentous fungi, which have a great agri-food and agronomic interest, particularly as bio-control agents, especially as fungicides, but which are not yet fully exploited. because of the difficulty to sporulate them in liquid culture.

For example, Pseudozyma flocculosa is a known strain of phyllosphere fungus epiphyte, belonging to the class Basidiomycetes and belonging to the order Ustilaginale.

Its definitive classification was established in 1995 by Boekhout on the basis of in-depth genetic analyzes. Currently, this fungus is classified as Pseudozyma related to the Ustilaginales of the phylum Basidiomycetes (Boekhout 1995). The complete taxonomy of this fungus is recorded in Table 1.

Table 1. Taxonomic description of Pseudozyma flocculosa (Taxonomy ID: 84751).

This fungus is recognized as a very effective biological control agent against white induced by

Erysiphe poligoni, several plants including rose and cucumber.

Moreover, the genus Trichoderma is also known to group a group of fungi that are commonly found in the soil, on dead wood, plant debris and the aerial part of plants.

Many species of Trichoderma have been found effective as biological agents against eg Pythium, Phytophthora cinnamomi, Rhizoctonia solanir Sclerotium rolfsiie and Cryphonectria parasitica. These pathogenic fungi cause significant damage to fruit, vegetable, greenhouse and ornamental crops.

The performance of Trichoderma atroviride as a biological control agent is due in part to the production of endochitinase and it has also been shown that this fungus intervenes, according to various mechanisms and at various levels, in the stimulation of root growth by the use of fertilizing minerals and the stimulation of natural plant defenses.

Furthermore, it is known that the fungi of the divisions of Zygomycetes, Ascomycetes and Basidiomycetes produce asexual spores called conidia, allowing them rapid vegetative propagation. On the other hand, in Deuteromycetes, also called imperfect fungi, the sexual cycle has never been observed and the reproduction is done only asexually, via the production of conidia.

Conidia or spores are the main means of protection, and conservation, fungal genomes, thanks to their resistance to conditioning treatments and hostile environmental conditions, such as extreme temperatures, ultraviolet rays and low light levels. 'relative humidity. For example, some of the conidia or spores of Aspergillus niger maintain their germinability after passage through an autoclave for one hour at 120 ° C (Morozova et al 2001).

In addition, the production of these asexual spores, or conidia, is essential in the life cycle of many fungi. It forms the primary means of dispersal for the fungal genome under adverse environmental conditions.

Many obstacles remain to be overcome in order to market fungal biological control agents based on filamentous fungi, especially because of their low ability to be stored over long periods, especially because of the low viability of conidia. or spores from a liquid fermentation.

Many fungi, including filamentous, can be grown in liquid media, that is to say during a so-called liquid fermentation phase. However, liquid fermentation is particularly problematic.

In this liquid environment, depending on the species, Hyphomycetes can be caused to develop in various forms, including thin-walled unicellular hyphae, some forms called blastospores, and submerged conidia or spores. These are obtained either directly from blastospores microcycles, by conidiation, or from conidiogenic cells that form on submerged hyphae.

In general, the preferred method for the production of conidia or spores on a large scale is the submerged culture because of a part of its good profitability, its short production time, and the availability of all the materials necessary for a liquid fermentation.

Despite all its advantages, the conidia or spores produced by this technique have too short a life in adverse environmental conditions. As a result, most biocontrol agents, based on conidia or submerged spores, require immediate use on pest infested plants and sites, whether fungal or insect-borne.

It is also possible to produce conidia by fermentation on a support or a solid substrate, also called phase or solid fermentation.

Although solid fermentation has been known for a long time, it has never experienced a real industrial boom and has often been abandoned for culture in liquid medium.

The solid fermentation has several difficulties with regard to many species of fungi. Paecilomyces fumosoroseus, for example, needs light for optimal production of aerial conidia (Wraight et al., 2001), and the efficient production of conidia of this fungal strain therefore requires surface culture, or periodic agitation of the media or particulate solid substrates, to increase the exposure to light. Verticillium conidia or spores, in turn, develop into sticky globules produced at relatively low densities on hyphae growth, whereas those of aschersonia must be produced in convolutions, or as pits in a dense stroma. .

In addition, the increase in temperature and the change in pH during the vegetative growth phase is a critical problem in the solid fermentation field (Smits et al., 1998).

The interest in fermentation in solid medium is not new, yet this mode of culture has never been developed because of difficulties in controlling the physico-chemical parameters of the culture. In fact, the massive production of conidia or spores must be initiated at a stage of vegetative development of the mycelium, during which it is necessary not only to maintain the optimal growth conditions (temperature, aeration, humidity, pH), but also to control the differentiation of the mycelium and prevent an early sporulation phenomenon that can greatly reduce production yield (Raimbault & Durand 1980).

In addition, the problem of heat removal, produced during the solid fermentation, seems particularly difficult to solve. Indeed, the heat released by the metabolic reactions, during the vegetative growth phase, can be deleterious if the temperature exceeds the allowed thresholds. It is the same for the evolution of the pH which is almost impossible to regulate in the absence of circulation of liquid (Pandey 2003).

To these difficulties, related to the fermentation is added another disadvantage, as important, related to the fact that at the end of culture we are with conidia or spores mixed with large amounts of mycelium and residues of the support or solid substrate, which can reduce the quality of the final product obtained and the application possibilities thereof, particularly in the agri-food field.

STATE OF THE ART The patent application WO2009 / 037399 describes a process for producing conidia or spores, and their metabolites, on a support, or substrate, solid by a conventional fermentation, the growth phase also being carried out on such a support. The solid medium must comprise a suitable solid support or substrate, that is to say a support or absorbent substrate of low density and practically non-fermentable, but impregnated with a culture medium suitable for the growth of conidia or spores of fungi . The process involves the application of water stress during the spore production phase.

The patent application EP2390345 describes the production of metabolites and other molecules of interest by fermentation in a solid medium on multiple supports or solid substrates, such as plant biomass, in particular agricultural products such as cereals, sub-products. -products of the agri-food industry, pulp or sewage sludge.

US Pat. No. 4,837,155 describes a method for producing the Trichoderma strain in the liquid phase and under aerobic conditions at temperatures of between about 25 ° C. and about 30 ° C. and at a pH of between about 5.8 and about 7.0, to generate from an inoculant a conidial density of at least 5 x 108 per ml, but without any solid support maturation phase.

EP0223809 discloses a process for producing conidia or spores of filamentous fungi in a rotary disk fermentor in the liquid phase.

It is also known to obtain accelerated composting through a combination of a liquid and solid fermentation generating a large amount of biomass on a fermentable non-inert support, which will be degraded by the development of the strains and which can become a compost comprising conidia of Trichoderma sp.

Thus, it appears that the methods known from the state of the art perform all steps of production of strains of fungi, or metabolites from these strains of fungi, either only in the liquid phase, or only in solid phase on a suitable substrate.

OBJECTS OF THE INVENTION The present invention aims to obtain strains of filamentous fungi of agronomic or agri-food interest, usable in solid form, in particular in the form of a powder, as well as a new process for obtaining these strains, in particular in the form of powder and which do not have the drawbacks of the state of the art.

In particular, the present invention aims to provide strains of filamentous fungi that are easily manipulated, have improved viability, especially after long storage times, and possibly high purity, ie strains essentially free of contaminants and / or residues of the culture medium, in order to be able to use them for agronomic or agri-food applications, in particular for the preparation of cheeses or cold meats.

Another object of the present invention is to obtain a process for obtaining said filamentous fungi, preferably in the form of powder of conidia or spores or of their primary or secondary metabolites, in particular a process which is rapid, of simple design, which has an efficient efficiency and whose physicochemical parameters of each stage are easily controllable.

A purpose of the invention is to provide a support or solid substrate suitable for the maturation of conidia or spores of filamentous fungi.

Characteristic Elements of the Invention The present invention relates to a process for obtaining conidia or spores of strains of filamentous fungi comprising the steps of: growing filamentous fungi during a first phase of mycelial growth in the liquid phase, to generate a mycelial biomass, mixing said obtained mycelial biomass with an inert solid support, generating conidia or spores during a second phase of maturation of said mycelial biomass on said inert solid support, optionally drying the conidia or spores obtained, and optionally extracting one or more molecules of interest conidia or spores obtained.

In the process of the invention, the inert solid support is the sound of a cereal, in particular wheat bran, preferably a tissue in which the cereal bran cells forming the inert solid support are devoid of of their fermentable fractions, in particular starch.

In the process of the invention, the maturation phase generates a concentration of conidia or spores, preferably between 3xE + 08 and 5x10 9 conidia / g for Pseudozyma flocculosa, and between E + 09 and 5x10 10 conidia / g, for Trichoderma atroviride and between 5xE + 8 and 1xE + 10 conidia / g conidia of Trichoderma harzianum.

In the process of the invention, the duration of conidia or spores is advantageously less than three weeks, preferably less than two weeks, more particularly less than one week.

According to the invention, the filamentous fungus is preferably of the genus Pseudozyma sp. , in particular Pseudozyma flocculosa, of the genus Tricoderma sp. , in particular Trichoderma harzianum, Trichoderma atroviride, Trichoderma hamatum, and Trichoderma viride, of the genus Penicilum sp. , especially Penicilium camemberti and

Penicilium nalgiovense, of the genus Metarhizium sp. or of the genus Bauveria sp.

Another aspect of the invention relates to the conidia or spores of strains of filamentous fungi obtained by the process of the invention, resistant to desiccation and stored in the dry state for a period greater than three months, preferably between three months and twenty-four months, or even more than twenty-four months, at an ambient temperature, that is to say a temperature of between about 15 ° C. and about 30 ° C., more particularly a temperature between about 20 ° C and about 30 ° C.

The invention also relates to conidia or spores of strains of mature filamentous fungi, of the genus Pseudozyma sp. , in particular Pseudozyma flocculosa, whose cytoplasmic fraction is charged with reserve and enriched with melanin.

Another aspect of the invention relates to a conidia or spore powder of the invention, in particular a conidia or spore powder obtained by the process of the invention.

The invention also relates to food compositions, in particular sausages and cheeses comprising the conidia, spores or conidia powder or spores of the invention.

A final aspect of the invention relates to the use of conidia, spores or conidial or spore powder of the invention against the proliferation of pests, in particular fungi, bacteria, viruses or viruses. insects, plants or fruits, to promote plant growth, in particular the growth of plant roots, germination and the cell growth rate of said plants. Preferably, this plant or this fruit is chosen from the group constituted by the rose bush, the cucurbits, in particular cucumber, squash or melon, tomato, strawberry, raspberry, gooseberry, grape, grape or grape. apple, apple, pear, pear, plum, plum and potato.

A final aspect of the present invention relates to the use of conidia, spores or the powder of conidia or spores of the invention for the preparation of food compositions, especially sausages and cheeses.

The present invention will be described in the detailed description below with reference to the figures presented by way of non-limiting illustrations of the invention.

BRIEF DESCRIPTION OF THE FIGURES [0050] FIG. 1 schematically represents the procedure for producing conidia or spore powder according to the invention, advantageously combining a first fermentation stage in the liquid phase generating mycelial biomass followed by a second stage of maturation, so-called phase of sporulation, in solid phase.

Figure 2 in A) is a binocular microscope observation G: 40x and which represents the structure of a wheat bran particle having undergone enzymatic curettage. These cells are emptied of their contents and acquire a honeycomb honeycomb structure highly aerated; in B) and C) are histological sections of about 50 μm of a fabric impregnated in an epoxy resin, after fixation with glutaraldehyde and osmium tetroxide and a revelation with toluidine blue B) is the cross section of a particle of sound before enzymatic treatment. The cells are loaded with reserves, and C) is the cross section of a particle of the sound derivative forming the inert solid support or substrate of the invention and used in the process of the invention. The cells are emptied of their contents following the successive enzymatic treatments, this new structure of the support or solid substrate inert the invention is conducive to a large liquid absorption capacity.

DETAILED DESCRIPTION OF THE INVENTION [0052] Many strains of fungi sporulate only slightly, randomly and not stable over time in liquid culture, which represents a major obstacle to their marketing and their applications.

The method according to the present invention combines, for the first time, a first so-called growth stage for generating a mycelial biomass in a medium or in a liquid phase and a second stage called maturation in a medium or in a solid phase on a support or suitable inert solid substrate, which is natural, that is to say obtained from renewable biological material, or which is synthetic, in particular dextran or agarose gel beads or a plastic derivative of petroleum, of preferably recyclable, such as expanded polystyrene in the form of beads or in an adequate cellular form.

Indeed, this support or solid substrate must have the following characteristics: be inert, non-degradable and nutrient-free, that is to say, no or little fermentable and therefore not or little accessible to bacterial development and degradation bacterial; have a honeycomb structure, very aerated conducive to optimal gas exchange and evaporation of water, that is to say a solid substrate or support having empty cells or cells with diameters of between about 2 microns and about 1000 pm, preferably between about 10 pm and about 500 pm; have a high capacity for absorption and retention of liquids, in particular water; that is, having the capacity to absorb between about 5 times and about 15 times, preferably between about 8 times and about 10 times, more particularly about 9 times its own weight in these liquids.

Preferably, this substrate or inert solid carrier of plant origin, essentially comprises tissues, the cells of which have retained their walls, but whose starch and the fractions of the cells most accessible to fermentation and bacterial development. (cellulose and hemi-cellulose) were removed. This substrate or inert solid support may be in the form of beads or fibers, and be produced from plant waste, such as straw, sawdust, beet pulp, olive grunts, coffee pulp, sugarcane bagasse and their mixtures.

Advantageously, this substrate or inert solid support is a derivative of cereals, preferably a derivative of wheat, or rice, more particularly wheat bran or rice, which is devoid of any trace of starch and dough. a large part of its cellulosic and hemi-cellulosic fibrous fraction, in particular following a sequential enzymatic treatment of this wheat bran, which will have the aforementioned characteristics and of which histological sections are shown in FIGS. 2A to 2C. This substrate or inert solid support of the invention, in particular this derivative of wheat bran, is used as an inert solid support or substrate for a second so-called maturation stage, in the absence of nutrients, of several species of filamentous fungi, especially conidia or spores of Pseudozyma flocculosa, Trichoderma Atroviride, Trichoderma Hazianum, Penicillium camemberti and Penicillium nalgiovense, Beauveria bassiana and Metarhizium anisopliae, or other species of filamentous fungi.

The use of the inert solid substrate or support according to the invention has the advantage of providing solutions to the major problems experienced by fermentation in solid medium. The massive inoculation of such a derivative of cereals, in particular of such a derivative of wheat bran, and the low water content of the mixture, but especially the fact that this derivative of cereals, in particular this derivative of wheat, also lacking nutrients, including any fermentable part present in plant tissue cells such as starch, can significantly reduce microbial contamination, particularly bacterial, in the solid phase.

According to the invention, the combination of two modes or steps of successive cultures, namely a first phase or liquid fermentation, followed by a second phase of solid phase processing on such a substrate or adequate inert solid support such as described above, makes it possible to advantageously control the growth parameters and to maintain them at their optimal values, without generating risks related to the excessive growths obtained in the processes of the state of the art and having the drawbacks of generating significant modifications of temperature and pH.

Indeed, as described in Figure 1, the first vegetative growth phase, said liquid phase 1, of a duration generally between about two days and about four days, generating heat and organic acids, is carried out in a fermenter according to conditions (temperature, pH, choice and quantity of nutrients added, stress induced or not, ...) well known to those skilled in the art and adaptable depending on the type of filamentous mushroom produced. The mycelium of the strain of this filamentous fungus massively generates a biomass 2. The physicochemical parameters followed by the fermenter are preferably as follows: Temperature: maintained between about 20 ° C. and about 40 ° C. Stirring speed: between about 70 rpm and about 250 rpm, with a P02 greater than 30%, preferably greater than 50% and more particularly greater than 80%. - pH: maintained between about 4 and about 7.8 (no pH regulation necessary in this production). - No stress induced during fermentation. Several culture media known to those skilled in the art can be used as: MAI (10 g malt extract). - MA2 (Malt extract 20 g). - MEA (malted extract 20 g, yeast extract 2 g) - YMPD (malted extract 5 g, yeast extract 3 g,

Dextrose 15 g, soy peptone 6 g) The biomass 2 obtained is then harvested and mixed, as represented by step 3 of FIG. 1, with an inert solid substrate or support, preferably consisting of a derivative starch-free wheat bran, to undergo a solid phase maturation step 4 of a duration generally of between about two days and about nine days, but variable depending on the type of filamentous fungus used, in order to generate these conidia or these spores. These conidia or spores can then advantageously be subjected to a drying step 5, generally lasting between about one day and about eight days, and a step of generating conidia or aerial spores 6, before a possible final separation treatment. or purification of the final product obtained in the form of a powder of conidia or spores. Since the substrate or the inert solid support according to the invention is advantageously non-fermentable, the maturation phase 4 does not require pH regulation and the little heat produced in the solid phase can be easily controlled by means of ventilation. In addition, this method is particularly effective and advantageously generates a large amount of these conidia or spores in a short time, preferably less than three weeks, less than two weeks, less than a week, or even less than one week. some days. Optionally, the process of the invention may also comprise a step of extraction and purification of primary or secondary metabolites or of any molecule of interest produced by these conidia or spores, in particular enzymes, such as amylases, phosphatases, proteases, vitamins, alkaloids, organic acids, flavors, pigments, lactones, melanin or antibiotics.

Therefore, the present invention provides a solution to the problems of the substrate culture or solid support, including the possible disadvantage of the heterogeneity of the final product obtained in the form of powder. Indeed, it is possible that at the end of the drying step 5, one finds oneself with aerial conidia mixed with large quantities of mycelium and solid support residues, for example wheat bran without starch, which are eliminated, or even recycled for a new maturation step, by an additional separation or purification step.

Another aspect of the invention relates to the conidia or spores obtained by the process of the invention, in particular conidia or spores of Pseudozyma flocculosa, the cytoplasmic fraction of which is completely transformed and is responsible for storage vesicles, and whose mitochondria and ribosomes are undetectable, which has never been observed before in the liquid culture mode of the same strains of filamentous fungi which are generally enriched in mitochondria and in free ribosomes which are markers of a metabolic activity and intense protein synthesis, no conducive to conservation.

Fluorescence microscopy analysis also reveals that by using the method of the invention, the conidia or spores obtained produce a fluorescent substance, it is an accumulation on the surface of the conidium or spore of melanin, which would be a form of protection against ultraviolet rays. This characteristic has never been observed before in conidia or spores produced in liquid culture mode. Conversely, conidia or spores from the submerged medium show a thinning of their wall.

Furthermore, another structural characteristic is the essentially concave appearance of the external shape of the conidia or spore obtained, which is specific to its high degree of maturation, in connection with the mode of dissemination of conidia or spores. by air. These characteristics have advantages in terms of harvesting, purifying and dispersing conidia or spores. In particular, the final step of separation and purification of the final product in powder form has the advantage of considerably reducing the presence of possible contaminants, such as mycelium or residues of the support or inert solid substrate used.

Examples

Example 1: Production of conidia of Pseudozyma flocculosa [0065] For the production of conidia or spores of Pseudozyma flocculosa, mycelia derived from liquid fermentation are matured with the inert solid support or substrate of the invention, which is a derivative wheat bran.

The stage of conidiation or of obtaining conidia, or sporulation, of two to seven days is followed by a drying step to obtain a final concentration of conidia or spores of Pseudozyma flocculosa after maturation of about from 3xE + 08 to 5x109 conidia / g. Plant protection or biological pest control tests carried out with these conidia or spores have shown an efficiency similar to that obtained with conidia or spores obtained by the methods of the state of the art.

Example 2: Production of Trichoderma harzlanum and

Trlchderma atroviride [0067] The two-day liquid fermentation step is followed by a condition step on the bran derivative for four to eight days, to obtain a final concentration, after ripening, of about 1E + 09 to 3x1010. conidia / g, Trichoderma atroviride conidia and 5xE + 8 to 1xE + 10 conidia / g Trichoderma harzianum conidia. References

Boekhout, T., 1995. Pseudozyma Bandoni emend. Boekhout, has genus for yeast-like anamorphs of Ustilaginales. The Journal of General and Applied Microhiology, 41 (4), pp. 359-366. Available at: https://vpn.gw.ulg.ac.be/article/jgarni955/41/4/41_4_359 /,DanaInfo=www.j stage.j st.go.jp, SSL + _article.

Morozova et al, 2001, Peculiarities of exogenous dormancy of Asperguilllus nigerconidia. Microbiololgy 70 (5), pp. 527-534.

Pandey, A., 2003. Solid-state fermentation. Biochemical Engineering Journal, 13 (2-3), pp. 81-84.

Raimbault, M. & Durand, G., 1980. Fermentation in Solid Media - Growth of Filamentous Fungi on Starchy Substrate, Available at: http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_5/pt5/travaux_d/00626.p df.

Smits, J.P. et al., 1998. The influence of temperature on kinetics in solid-state fermentation. Enzyme and Microbial Technology, 22 (1), pp. 50-57.

Wraight, S.P. et al, 2001. Productionr Stabilization and Formulation of Fungal Biocontrol Agents,

Claims (24)

A process for obtaining conidia of strains of filamentous fungi comprising the steps of: growing filamentous fungi during a first phase of mycelial growth in the liquid phase, to generate a mycelial biomass, mixing said obtained mycelial biomass with an inert solid support, and generating essentially without fermentation conidia and / or spores during a second phase of maturation of said mycelial biomass on said inert solid support. 2. The method of claim 1, further comprising a step of drying the conidia. 3. The method of claim 1 or 2, further comprising a step of extracting one or more molecule (s) of interest conidia. 4. The process according to any of the preceding claims, wherein the inert solid support is cereal bran. 5. The method of claim 4 wherein the cereal is wheat. 6. The method of claim 4 or claim 5, wherein the sound cells of the cereal forming the inert solid support, are free of their fermentable fraction, in particular starch. The method according to any one of the preceding claims, wherein the maturation stage generates a conidium concentration of between 3xE + 08 conidia / g and 5x109 conidia / g for Pseudozyma flocculosa, and between I + 09 conidia / g and 5x1010 conidia / g, for Trichoderma atroviride and between 5xE + 8 conidia / g and 1xE + 10 conidia / g conidia of Trichoderma harzianum. 8. The method according to any one of the preceding claims, the duration of conidia obtaining is less than 3 weeks, preferably less than two weeks, more particularly less than 1 week. 9. The method according to any one of the preceding claims, wherein the filamentous fungus is of the genus Pseudozyma sp. , in particular Pseudozyma flocculosa. The method of any one of the preceding claims 1 to 8, wherein the filamentous fungus is of the genus Trichoderma sp. , in particular Trichoderma harzianum, Trichoderma atroviride, Trichoderma hamatum and Trichoderma viride 11. The method according to any one of the preceding claims 1 to 8, wherein the filamentous fungus is of the genus Penicillium sp. , in particular Penicilium camemberti and Penicilium nalgiovense. The process according to any one of the preceding claims 1 to 8, wherein the filamentous fungus is selected from the group consisting of Metarhizium sp. and Bauveria sp. 13. Conidia of strains of filamentous fungi obtained by the method according to any one of the preceding claims, resistant to drying and stored in a dry state at room temperature, for a period greater than one month or two months, preferably during a period of between three months and twenty-four months. 14. Conidia and / or spores of mature filamentous fungus strains of the genus Pseudozyma sp. , in particular Pseudozyma flocculosa, whose cytoplasmic fraction is charged with reserves and rich in melanin. 15. Conidia of strains of filamentous fungi according to claim 14 is obtained by the method according to any one of claims 1 to 9. 16. Conidia powder and / or spores according to any one of the preceding claims 13 to 15. 17. A food composition comprising the conidia or the conidia powder according to any one of the preceding claims 13 to 16. 18. Food composition according to claim 17, characterized in that it is chosen from the group consisting of meats and cheeses. 19. Use of conidia or a conidia powder according to any one of the preceding claims 13 to 16, against the proliferation of pests of plants or fruits. 20. Use of conidia or a conidia powder according to any one of the preceding claims 13 to 16, for promoting the growth of plants. 21. Use according to claim 20 for promoting plant growth, in particular germination and the rate of cell and root growth of plants. 22. Use according to any one of the preceding claims 19 to 21, wherein the plant or the fruit is chosen from the group consisting of the rose bush, the cucurbits, in particular, the cucumber, the squash or the melon, the tomato, strawberry, raspberry, currant, grape, grape, apple, apple, pear, pear, plum, plum and potato. 23. Use of conidia or a conidia powder according to any one of the preceding claims 13 to 16 for the preparation of a food composition. 24. Use according to claim 23, wherein the food composition is selected from the group consisting of sausages and cheeses.