Concentrated algal extract, method for its production and its use in agriculture

Abstract

The present invention relates to a concentrated algal extract containing 6-100% dry matter, a method for its production, and its use, alone or in combination with another nutrient, biostimulant or plant health technology, to stimulate plant emergence, growth, development and reproduction, and to prevent bird seed predation, in particular. The present invention also relates to a method for applying the concentrated algal extract of the present invention, and to seeds coated with said extract.

Description

[0001] This application is a divisional application of the invention patent application filed on September 11, 2015, with application number 201580048749.6 and entitled "Concentrated Algae Extract, Its Production Method and Its Use in Agriculture". Technical Field

[0002] This invention relates to concentrated algal extracts with a dry matter percentage of 6-100%, methods for their preparation, and their use, alone or in combination with another nutrient, biostimulant, or plant protection technique, to particularly promote plant germination, growth, development, and reproduction, and to prevent birds from eating seeds. The invention also relates to methods of applying the concentrated algal extracts of this invention, and seeds coated with said extract. Background Technology

[0003] Increasing yield is the primary concern for farmers. Yield depends mainly on the good development and growth of the plants, as well as their good health.

[0004] Plant growth is directly related to the absorption and assimilation of mineral elements, as well as the flow of hormones that regulate plant tissue elongation and differentiation. Therefore, nutrients and hormones are crucial for plant growth. Since plants are immobile, they have developed activating or activatable mechanisms that enable them to utilize existing resources to the fullest extent possible to promote their growth. Fertilizers are used to accelerate this growth.

[0005] For many years, algae have been used as organic fortifiers in various soil types and on a wide range of commercially available horticultural and cereal crops. Algae extracts are used as biostimulants and are frequently sprayed onto plant leaves. Numerous beneficial effects associated with the use of algae extracts in agriculture have been observed, including increased yield, improved nutrient supply, resistance to frost and stress conditions, improved fruit shelf life, and reduced fungal and pest attacks.

[0006] Algae extracts are also known to allow for better seed germination, particularly by promoting plant emergence. In fact, once plants emerge, seedlings are susceptible to pathogenic microorganisms such as fungi (e.g., Rhizoctonia solani root rot, Pythium) or bacteria that cause a disease called damping-off. Attacked seedlings eventually collapse to one side, as if the base of the stem had been pinched off. Air humidity and low temperatures promote the development of damping-off.

[0007] Many algae extracts sold are used in agriculture. For example, the applicant discloses a composition from seaweed obtained according to a method comprising the following steps in patent EP0538091:

[0008] a) Hydrolyze at least one brown algae base at a temperature of 50-100°C for 4-8 hours in the presence of a reducing agent;

[0009] b) Neutralize the hydrolysate obtained in this manner with a strong acid until a pH of 6-8 is obtained;

[0010] c) Filtration;

[0011] d) Optionally, percolate or electrodialyze the filtrate obtained at the end of step c); and

[0012] e) Optionally, the filter obtained at the end of step c) or the residue obtained at the end of step d) is reduced to its powder.

[0013] However, due to the basic hydrolysis of algae under thermal conditions in the presence of a reducing agent, some compounds in the algal intracellular fluid are not retained, especially polysaccharides, lipids, proteins, and polyphenols, which reduces the biostimulatory properties of the compositions obtained by the above method.

[0014] The inventors have discovered that algal extracts containing compounds that retain intracellular fluid of algae, when concentrated to a certain percentage of dry matter, exhibit excellent biostimulatory activity. Unexpectedly, the applicants observed that, upon application in comparable amounts, the concentrated algal extract of the present invention is more effective than diluted extracts in stimulating plant germination and promoting plant growth. Furthermore, when the concentrated algal extract is used to coat seeds, the coated seeds are less likely to be attacked by birds than uncoated seeds. Summary of the Invention

[0015] One subject of the present invention is a concentrated algae extract with a dry matter percentage of 6-100%, preferably 9-70%, more preferably 12-50%, containing 0-5%, especially 1-4%, and even more particularly 2-3% alginate and / or cellulose relative to the weight of the extract.

[0016] The second subject of this invention is a method for preparing a concentrated algal extract according to the invention, comprising the following steps:

[0017] – Grind the algae until the cells rupture;

[0018] - Homogenize the ground algal material in an aqueous solution;

[0019] -Alginate and cellulose are removed through flocculation and filtration;

[0020] –Optionally, adjust the pH of the filtrate;

[0021] – The filtrate is concentrated to obtain a dry matter percentage of 6-100%, preferably 9-70%, more preferably 12-50%.

[0022] Another subject of the present invention is a method for promoting plant emergence, growth, development and / or reproduction, characterized by applying an extract according to the invention or an extract prepared according to the method of the invention by permeation into the soil, spraying onto plant leaves, applying to seeds before sowing, or applying to the roots of seedlings, particularly by immersion treatment, before planting.

[0023] Another subject of the present invention is the use of extracts according to the invention or extracts prepared by the method according to the invention for promoting plant growth.

[0024] Another subject of the present invention is the use of extracts according to the invention or extracts prepared by the method according to the invention for stimulating plant germination.

[0025] The sixth subject of this invention is the use of extracts according to the invention or extracts prepared by the method according to the invention as bird repellents.

[0026] Finally, another subject of the invention is seeds coated with an extract according to the invention or an extract prepared by the method according to the invention.

[0027] The concentrated algae extract of the present invention is particularly of a dry matter percentage of 6-100%, preferably 9-70%, more preferably 12-50% aqueous or dry extract.

[0028] Within the meaning of this invention, the percentage of dry matter is calculated according to the following formula:

[0029]

[0030] in,

[0031] m 干燥 It is the weight of the substance retained after drying; and

[0032] m 水合 This is the weight of the algae extract before drying.

[0033] The concentrated algal extract of the present invention does not contain alginate and / or cellulose. Therefore, the algal extract according to the present invention comprises intracellular fluid of algae, obtained after rupturing the algal cell wall and removing the cell wall by flocculation. According to a specific embodiment, the concentrated algal extract of the present invention contains 0-5%, particularly 1-4%, and more particularly 2-3% alginate and / or cellulose relative to the weight of the extract.

[0034] The algae from which the concentrated extract of the present invention is obtained are particularly selected from: *Ascophylum nodosum*, *Fucus vesiculosus*, *Laminaria digitata*, *Laminaria hyperborea*, *Laminaria saccharina*, *Eklonia maxima*, *Sargassum* spp., and mixtures thereof. According to one specific embodiment, the algae is *Ascophylum nodosum*.

[0035] The concentrated algae extract of the present invention has a pH of 1.5-9, preferably 2-7, and more preferably 2.5-3.

[0036] The concentrated algal extract of the present invention comprises intracellular fluid of algae. It may in particular contain one or more compounds selected from the following: polysaccharides, such as, especially, kelp polysaccharides and fucoidan; free and conjugated sugars; polyphenols; mannitol; growth hormones; lipids; proteins; amino acids; vitamins; betaine; sterols; glucuronic acid; and mineral salts. According to a specific embodiment, the concentrated algal extract of the present invention comprises kelp polysaccharides; Dunaliella salina; lipids; proteins; and polyphenols.

[0037] According to one specific embodiment, the concentrated algae extract of the present invention can be formulated as a composition comprising the extract and at least one compound selected from: gelling agents, thickeners, plant protection products, a second plant and / or algae extract, minerals, surfactants, oils, preservatives, and mixtures thereof.

[0038] The concentrated algae extract of the present invention can be obtained in particular by the following method.

[0039] The method for preparing the concentrated algal extract according to the present invention comprises the following steps:

[0040] – Grind the algae until the cells rupture;

[0041] - Homogenize the ground algal material in an aqueous solution;

[0042] -Alginate and cellulose are removed through flocculation and filtration;

[0043] –Optionally, adjust the pH of the filtrate;

[0044] – The filtrate is concentrated to obtain a dry matter percentage of 6-100%, preferably 9-70%, more preferably 12-50%.

[0045] Advantageously, the method of the present invention does not include a step of hydrolysis at a temperature of 50-100°C for 4-8 hours in the presence of a reducing agent. In fact, this preserves compounds, especially polysaccharides, in the intracellular fluid of algae.

[0046] The grinding process, in particular, can rupture the cell walls of algae, thereby releasing the intracellular fluid. The grinding process is preferably carried out on fresh algae, i.e., algae harvested within the last 24 hours.

[0047] The homogenization of the ground algae material can be carried out in particular by adding water at a rate of 1-2 liters per kilogram of ground algae material.

[0048] The flocculation and filtration steps can remove algal cell wall residues in particular to recover the algal intracellular fluid. Algal cell wall residues can be precipitated, in particular, by flocculation or by adding acid, especially hydrochloric acid, to the ground algal material. According to one embodiment of the invention, acid is added to obtain a pH of 1.5-4, preferably 2-3.5, more preferably 2.5-3.

[0049] The acidified mixture was then filtered to remove alginate and cellulose flocs larger than 40 μm.

[0050] Optionally, the pH of the filtrate can be adjusted by adding acid or alkali to obtain a pH of 1.5-9, preferably 2-7, and more preferably 2.5-3.

[0051] The process of concentrating the filtrate can be carried out in various ways, such as reverse osmosis, water evaporation, algae enrichment, or centrifugation.

[0052] Reverse osmosis is a membrane separation technology based on a selective diffusion process. Two algal extracts of different concentrations are placed on opposite sides of a water-permeable membrane. When pressure is applied to the more concentrated algal extract, some of the water in the more concentrated extract moves to the less concentrated extract.

[0053] Moisture can be evaporated, in particular, by heating the algae extract under reduced pressure, for example, using a rotary evaporator. Heating can be carried out at 40-90°C, preferably 60-80°C.

[0054] Algae enrichment can be achieved, in particular, by replacing the water with an algae suspension obtained according to the method of the invention during the homogenization step of the milled algae material according to the method of the invention.

[0055] Centrifugation can be performed by subjecting the algal extract to centrifugal force in a high-speed rotating machine.

[0056] The concentration of the filtrate is preferably carried out by water separation and evaporation.

[0057] The concentrated algae extract according to the invention is advantageously used in agriculture, and has a variety of applications depending on the type of plant applied and the stage of the plant cycle during application.

[0058] The concentrated algae extract of the present invention can be used alone or in combination with nutrient, biostimulant or plant protection compositions.

[0059] The concentrated algae extract of this invention can be used on agriculturally useful plants, such as vegetables, fruits, cereal crops, and ornamental plants. Agriculturally useful plants are selected from the following angiosperms: Apiaceae, Asteraceae, Brassicaceae, Chenopodiaceae, Convolvulaceae, Cucurbitaceae, Fabaceae, Gramineae, Liliaceae, Polygonaceae, Rosaceae, Solanaceae, Poaceae, and Vitaceae. According to one specific embodiment, the concentrated algae extract of this invention is used on tomatoes, rice, soybeans, fruit trees, grapevines, wheat, or corn.

[0060] Therefore, when the concentrated algae extract of the present invention is used to promote plant growth, the extract can be applied, particularly by foliar spraying, soil application, or root infiltration. It can be applied once or more per week throughout the plant's growth cycle. Very beneficial results have been shown on tomato and corn seedlings.

[0061] When the concentrated algae extract of the present invention is used to stimulate plant emergence and / or to provide a bird-repellent effect, the extract can be applied to seeds, particularly before planting or immediately after seedling emergence. Seeds can be coated, in particular, with the concentrated algae extract of the present invention. Coating can be performed, for example, by wetting the seeds with the extract and preferably drying them at room temperature. It can be applied at a rate of 10-120 g, preferably 20-110 g, more preferably 30-105 g of the concentrated algae extract per kg of seeds. Very beneficial results have been shown on corn seeds.

[0062] The coated seeds, which are a subject of this invention, can be prepared in particular as described in the preceding paragraphs. Coating seeds with the concentrated algae extract of this invention results in faster germination and increased resistance to damping-off compared to uncoated seeds. Furthermore, the coated seeds according to this invention are less susceptible to attacks from birds, particularly crows, pigeons, larks, partridges, and pheasants, compared to uncoated seeds.

[0063] The invention will now be described in more detail by way of the following embodiments, which are given in an illustrative manner only. Attached Figure Description

[0064] Figure 1 This is a schematic diagram showing the number of corn seedlings obtained 3 weeks after sowing uncoated corn seeds, corn seeds coated with the algae extract of the present invention, or corn seeds coated with a conventional fungicide, as described in Example 4.

[0065] Figure 2 This is a schematic diagram showing the number of corn seedlings obtained 3 weeks after sowing uncoated corn seeds, corn seeds coated with the algae extract of the present invention, or corn seeds coated with a conventional fungicide, as described in Example 5. Detailed Implementation

[0066] Example 1: Preparation of concentrated algal extract

[0067] The extract of *Leptochloa crus-galli* (named GOACTIV by the applicant company) with a dry matter percentage of 5.1% was concentrated by evaporating water in a rotary evaporator under vacuum (with a water pump) at 50°C until the dry matter percentage reached 13%.

[0068] Example 2: Application of concentrated algae extract to tomato seedlings

[0069] Spray the extract onto the leaves of 3-leaf tomato seedlings once a week (for 3 weeks), using the amount per plant shown in the table below.

[0070] % dry matter 5.1％ 13％ Amount of extract sprayed per seedling 0.03mg 0.01mg

[0071] Then, tomato seedlings were treated with a considerable amount of each extract.

[0072] After 5 weeks of treatment, tomato seedlings treated with the concentrated algae extract of the present invention (Example 1) were taller and denser than seedlings treated with the unconcentrated algae extract (GOACTIV).

[0073] Therefore, for a given amount of extract, the concentrated algae extract of the present invention is more effective than a diluted extract in promoting the growth of tomato seedlings.

[0074] Example 3: Coating corn seeds with concentrated algae extract

[0075] In a rotary mixer, 100 kg of corn seeds were moistened with 100 g of the concentrated algae extract prepared in Example 1. The seeds were then dried at 20-25°C for 24 hours.

[0076] Example 4: The effect of seed coating on corn seedling emergence

[0077] At 20m 2 The coated maize seeds prepared in Example 3 were sown in the field. Untreated maize seeds were used as a control. Comparative tests were conducted using maize seeds coated with a conventional fungicide containing 25 g / L fludioxonil and 9.7 g / L metalaxyl-M.

[0078] Three weeks after sowing, the number of corn seedlings was counted. The results are as follows: Figure 1 As shown. It was observed that seeds coated with the concentrated algae extract prepared according to Example 1 were more conducive to the emergence of maize seedlings compared with uncoated seeds or seeds coated with a fungicide.

[0079] Repeating Example 4 yielded similar results.

[0080] Example 5: Bird-repelling effect of seed coating

[0081] In an experiment according to Example 4, the field was subjected to particularly intense attacks by crows. The birds attacked the seeds buried in the soil, resulting in a decrease in the number of healthy corn seedlings relative to the number of seeds planted.

[0082] The results are as follows Figure 2 As shown, the values ​​on the y-axis represent the percentage of healthy corn seedlings relative to the theoretical number of seedlings.

[0083] Significant differences in the degree of attack were observed between control fields or fields treated with fungicides and fields in which seeds were coated with the concentrated algae extract of Example 1. Therefore, fields in which seeds treated with the concentrated algae extract of Example 1 were relatively spared from birds.

[0084] Therefore, the concentrated algae extract of the present invention has a bird-repelling effect.

[0085] Repeating Example 5 yielded similar results.

Claims

1. A method for preparing concentrated algal extract, characterized in that, It contains 6-100% dry matter and 0-1% alginate and cellulose relative to the weight of the extract, wherein the algae are selected from *Lactobacillus thuringiensis*, *Fucus vesiculosus*, *Kelpia palmata*, *Kelpia serrata ... and *Kelpia serrata*. Eklonia maxima Sargassum and mixtures thereof, the method comprising the following steps: – Grind the algae until the cells rupture; - Homogenize the ground algal material in an aqueous solution; -Alginate and cellulose are removed through flocculation and filtration; –Optionally, adjust the pH of the filtrate; –Concentrate the filtrate to obtain a dry matter percentage of 6-100%. The algal intracellular fluid is retained, and the extract contains kelp polysaccharides, fucoidan, lipids, proteins, and polyphenols.

2. The preparation method according to claim 1, characterized in that, The process of concentrating the filtrate is carried out through reverse osmosis, water evaporation, algae enrichment, or centrifugation.

3. The concentrated algae extract obtained by the method according to any one of claims 1 or 2.

4. The concentrated algae extract according to claim 3, characterized in that, Its pH ranges from 1.5 to 9.

5. A method for promoting plant emergence, growth, development and / or reproduction, characterized in that, The extract as described in any one of claims 3 or 4 may be applied by infiltration into the soil, sprayed onto plant leaves, applied to seeds before sowing, or applied to the roots of seedlings by immersion treatment before planting.

6. Use of the extract according to any one of claims 3 or 4 for promoting plant growth.

7. Use of the extract according to any one of claims 3 or 4 for stimulating plant germination.

8. Use of the extract according to any one of claims 3 or 4 as a bird repellent.

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