WO2019025668A1

WO2019025668A1 - Method for keeping chlorella alive and fresh for consumption thereof

Info

Publication number: WO2019025668A1
Application number: PCT/FR2018/000201
Authority: WO
Inventors: René-Jean GUILLARD
Original assignee: Skyworld International Overseas Limited
Priority date: 2017-08-03
Filing date: 2018-08-03
Publication date: 2019-02-07
Also published as: EP3662062A1; FR3073229A1

Abstract

The present invention relates to a method for keeping chlorella alive and fresh for consumption thereof. According to the invention, such a method is characterised in that it involves exposing a chlorella concentrate (24), comprising between 20 x 106 and 109 cells per millimetre, to a light source (10), while moving (28) said concentrate, so as to place this chlorella concentrate in a stress situation so that it produces its metabolism itself, namely chlorelline, which will protect its concentration medium and thus extend the duration during which the chlorella charged with chlorelline can be consumed. Applicable to human and animal food.

Description

METHOD FOR PRESERVING LIVING AND FRESH CHLORELLE

FOR CONSUMPTION

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for the preservation of chlorella, living and fresh, for consumption, useful elements from a concentrate of microalgae, and a production device for the implementation of such a method.

BACKGROUND OF THE INVENTION Microalgae are increasingly used because of their compositions rich in elements such as amino acids, vitamins A, B, C and E, unsaturated essential fatty acids, vegetable proteins , minerals of iron, calcium, sulfur, zinc, potassium, magnesium and manganese, lipids or antioxidants. Because of their compositions, micro-algae are used for human nutrition, especially as food supplements.

Micro-algae are already widely used for health and cosmetics (shampoos, facial and hand cleansers), but also as feed for animals, as a biofuel, or for green chemistry. producing in particular plastics and technical oils.

However, for reasons of compromise, logistics, administration or stability, most dietary supplements based on micro-algae are currently proposed in human nutrition only in a dehydrated form, that is to say say in a form clearly depleted of vitamins. It is also known to produce microalgae from hydroponics grown in transparent tubes called photo-bioreactors "PBR", which receive a liquid containing nutrients "NPK" rich in nitrogen, phosphorus and potassium, as well as carbon dioxide dissolved in this liquid, in order to quickly synthesize the biomass.

The culture medium used can, according to different situations called "culture stress", give a product rich in active substances released by the microalga such as toxins, probiotics or antibiotics, omega 3 for example. Thus, the production of chlorelin can be favored in the particular case of chlorella culture, also called "Chlorella vulgaris", which is a species of microscopic unicellular green algae of the family Chlorellaceae. Chlorella vulgaris is indeed interesting in many ways: thanks to photosynthesis, it reproduces very quickly in fresh water in areas with high sunshine and relatively temperate temperatures; it is considered one of the richest plants in chlorophyll; it has remineralising and elimination properties; it is believed to stimulate the immune system through Chlorella Growth Factor (CGF), a substance that would accelerate cell growth and help maintain cell integrity. As for chlorelin, it acts as a natural antibiotic, that is to say that, unlike chemical antibiotics, it fights pathogenic bacteria without altering the intestinal flora.

As for the microalgae harvest, that is to say, their separation from their culture medium when they have reached maturity, the said harvest is generally obtained by centrifugation of the whole of biomass, which is more or less pure to the extent that it may contain other micro-algae or bacteria for example. We this dehydrate is then dehydrated to recover a micro-algae-rich powder, which is compact, which facilitates and reduces packaging and shipping costs.

However, these processes for treating microalgae by centrifugation pose problems of degradation of the qualities of the product obtained. In particular, these treatments deteriorate the essential nutrients contained in micro-algae and they can in addition destroy almost all (up to 80%) of the vitamins contained in it. In addition, since the structure of the cells to be harvested is extremely fragile, it is understood that the centrifug harvesting operation is delicate and of low yield. Finally, the dehydration treatment does not take any account of the culture medium.

Harvesting microalgae by filtration, flotation or sedimentation is no more profitable because, in each of these processes, it is essential to use a very large amount of water, which implies a significant consumption of water. energy to maintain the necessary water circulation and hence significant expenditures out of proportion to the benefits derived from the harvest.

Moreover, in this respect, the applicants of the present patent application file that same day another patent application which describes and claims an original method of harvesting micro-algae by filtration which leads to significantly improved results, and without the need for significant investments in equipment. *

It is therefore by advantageously using this process, although this is by no means obligatory, that the technique which is the subject of the present invention will be put into practice, the aim of which is to preserve as long as possible, alive and fresh, concentrated chlorella. for consumption. GENERAL DESCRIPTION OF THE INVENTION

It was previously reported that, according to different situations called "stress culture" or "physiological forcing" it is possible to obtain from a concentrate of micro ^¬ algae, altered metabolism of said micro-algae will promote or even force it to produce at least one metabolite.

Until today, the metabolite (s) thus produced by the microalgae are extracted from the biomass using various solvents, for example fatty acids.

The FR-2696475 patent application published April 8, 1994 teaches various ways and conditions for placing the micro ^¬ concentrated algae in a situation ensuring the production of metabolites and then harvest biomass containing metabolites and / or the medium containing these metabolites.

The life span of chlorella is of the order of two to three days that it was its mode of culture, either in basin or photobioreactor. This lifetime could be increased somewhat, that is doubled, if the chlorella is forced to produce its metabolite, namely chlorelline, which is remembered as an antibiotic.

Indeed, the excretion of chlorellin prevents cell multiplication and thus prevents the appearance of bacteria that destroy chlorella.

Notwithstanding these 25 years old knowledge and the interest that the consumption of chlorella, and even more that of chlorellin, could represent for the health of humans and animals, nothing has been done in this direction.

The present invention aims to remedy this gap.

It proposes for this purpose a conservation method of chlorella, lively and fresh, with a view to its consumption, said method being remarkable in that it consists in exposing a chlorella concentrate comprising between 20x10 ^and 10 ⁹ cell per milliliter a light source, while making a bet in movement of said concentrate, so as to place this chlorelle concentrate under stress so that it produces its own metabolism, namely chlorelline, which will protect its concentration medium and thus prolong the duration during which the chlorella loaded chlorelline can be consumed.

An advantage of this method of producing chlorellin is that culture stress is achieved by exposure to light radiation of a highly concentrated chlorella concentrate, thereby allowing cellular respiration of the photosynthetic system of chlorella and promoting the production of chlorelline. Moreover, with simultaneous permanent mixing of this concentrate after its setting in motion, the complete mass of the chlorella is uniformly exposed to the radiation. Thus, whole chlorelle, living, under stress is placed in order to impose a continuous production of chlorelline, essential for its maintenance away from bacteria, its contamination and therefore the disappearance of chlorella.

A high and simple production of chlorellin is thus obtained quickly and easily.

The production method according to the invention may further comprise one or more of the following characteristics, which may be combined with one another.

Advantageously, the production process exposes the concentrate to the light source periodically.

Advantageously, the production process comprises an additional step consisting of a supplementation of nitrogen NPK in the concentrate.

The invention also relates to a device for producing chlorellin from harvested chlorella, said device comprising means implementing a production process comprising any one of the preceding characteristics. Thus, according to one embodiment, the production device comprises a reactor having transparent walls, using a light source which is indifferently then located outside or inside said reactor.

In particular, the reactor can be made in the form of a transparent tube arranged vertically.

Advantageously, the light source inside or outside said device comprises LED light emitting diodes having a light spectrum corresponding to solar radiation.

Advantageously, the production device according to the invention comprises a mobile mechanical system or an air bubble injection device capable of achieving movement within the concentrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed specifications of the invention are given in the following description in conjunction with the accompanying drawings. It should be noted that these drawings have no other purpose than that of illustrating the text of the description and that they therefore in no way constitute a limitation of the scope of the invention.

In these drawings:

- Figure 1 is a diagram showing the different steps from the cultivation of chlorella to the chlorelline production process; and

FIGS. 2 and 3 show diagrams of a reactor implementing the production method according to the invention, respectively for an industrial installation and for a domestic installation. DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 schematically illustrates a first step 2 comprising the cultivation of chlorella, in particular in transparent tubes of PBR photo-bioreactors installed for example in greenhouses, in order to make optimum use of the solar radiation.

Advantageously, a culture is carried out in a confined environment which makes it possible to limit or eliminate all the risks of contamination of the concentrate coming from the outside.

Then, in a second step 4, the harvest of the microalgae of the culture is advantageously carried out in a gentle manner in order to avoid destruction of the chlorella cells.

In a third stage 6 using a concentrator, a microalgae concentrate 24 is produced, for example with a plate filter or a membrane, in order to obtain a high concentration of chlorella of between 20 million and 1 billion cells per milliliter. (ie 0.6 to 30g / l).

Then, in a fourth step 8, the chlorella concentrate 24 is inserted into a reactor comprising a closed vessel which nevertheless makes it possible to expose the product contained in said tank to a light source 10 in order to carry out the photosynthesis. Thus, the light source 10 may be external, and in this case the walls of the tank are transparent, or internal with then opaque tank walls.

As a light source internal or external to the reactor, it is possible to use LEDs that, for example, have a broad light spectrum corresponding to solar radiation.

Advantageously, the light source 10 emits periodically, with further periods that can be adjustable, to allow cellular respiration of the photosynthetic system of chlorella. In parallel with the exposure to the light source 10, the movement of the entire mass of the concentrate 24 is carried out in a very gentle manner so as to expose in the most regular manner the whole from this matter to the luminous radiation, and thus to obtain a homogeneity of its evolution.

Chlorella has a reaction, when its cell concentration becomes too high, to no longer develop and emit in its environment a production of antibiotic, this antibiotic proving indeed essential to keep away from bacteria. The reaction of the cells is in a way a protective reflex. Thus, a culture stress is achieved in which the chlorella thus avoids its contamination and its disappearance.

In other words, it is the fact of keeping concentrated and alive microalgae of the type Chlorella Vulgaris which allows the production of chlorelline, here sought.

This chlorellin production is effective for concentrations of chlorella in the concentrate of between 20x10 ⁶ and 10 ⁹ cells per milliliter.

The chlorelle concentrate 24 thus treated develops a large production of chlorelin for a period of up to 30 days, before drawing this concentrate by an outlet valve 30.

In order to be able to extend this period of production, a nitrogen supplement NPK will be advantageously introduced into the reactor, which will have the effect of feeding the chlorella, which will then be able to continue to multiply very slightly, in this connection having a tendency to die.

FIG. 2 represents, in the perspective of an industrial installation, a reactor 14 comprising a cylindrical tank 20 made of stainless steel, arranged horizontally on legs 16. The tank 20 may have a volume of, for example, between 1 and 5 m ³ . The top of the tank 20 comprises a hatch 22 allowing the introduction of the chlorella concentrate 24. The base of one end of the tank comprises an outlet valve 30 allowing the extraction of the product obtained after a reaction time, which is enriched in chlorelline.

The tank 20 comprises inside, in the upper part, a light source comprising a lighting 10 connected to an external power supply, delivering light radiation periodically to effect photosynthesis of the concentrate 24.

The tank 20 comprises on the top a smooth mechanical stirring system 26, comprising an electric motor driving mixing blades 32 which have a geometry and a rotational speed designed not to degrade the cells of micro-algae.

The tank 20 also has at one of its ends a bubbling system 28, in order to inject at the base of the concentrate 24 bubbles which generate in addition a movement of the material.

Alternatively, it is possible to use a single stirring system, comprising either only the mechanical stirring system 26 or the bubbling system 28.

FIG. 3 shows a reactor 18 for a more domestic installation comprising a transparent tube 40 arranged vertically and having at its upper end an opening closed by a plug 42, allowing the introduction of the chlorella concentrate 24. The volume of this domestic reactor can be of the order of 1 to 5 liters, and preferably close to 2 liters.

The tube 40, placed on a support 44, has at its base an outlet valve 30 for extracting the enriched product, and next to a bubbling system 28 to introduce the bottom of the concentrate 24 air bubbles which will go up along the column formed in the tube 40, to stir the concentrate of microalgae. The bubbling system 28 is made simply by a small air pump.

The reactor for domestic installation made very simply and economically, preferably using solar radiation as light source 10, can be made in the form of a transparent tube 40 having for example a diameter of 9 cm and a height of 60 cm.

In general, tests were carried out in vivo on various farm animals, in particular a breeding of laying hens and a breeding of hens, with a daily intake of chlorella concentrated in their culture medium, a contribution which is injected into the drinking water of the hens by a metering pump to obtain a concentration of 0.2% at

0.6% / volume of water, or 2 to 6g per liter.

In parallel, all these hens have been removed from the diet with synthetic antibiotics commonly used for intensive breeding.

After a review performed after seventy weeks of tests, because of the contribution for 1000 chickens of a solution of chlorella / chlorelline dosed at 600 g per day, it was noted on these farms a 5% reduction in feed consumption by animals, a 3% increase in the number of eggs laid, an improvement in shell thickness of these eggs, an improvement in the quality of droppings showing a lack of diarrhea, which reduces the soiling of eggs, and a significant decrease in chicken mortality, of the order of 3%.

All these factors make it possible to significantly improve the economic conditions of the farms, representing several times the cost of the dietary supplement based on microalgae. The profitability of the chlorella put under stress situation is assured, and all the more so that the food was made with a simultaneous abandonment of the use of synthetic antiobiotics. Transposed to human nutrition, an average consumption of concentrated chlorella, living, and put under stress situation would be 50 to 150 milliliters / day at a rate of 200 million cells per milliliter, that is between 10 and 30 billion cells ingested with their culture medium rich in chlorelline.

It goes without saying that the invention is not limited to the only preferred embodiments described above.

On the contrary, it embraces all the possible variants of embodiment, insofar as the latter do not go beyond the scope delimited by the appended claims which define the scope of the present invention.

Claims

1 - A method of preserving chlorelle, living and fresh, for consumption, said method being remarkable in that it consists in exposing a chlorella concentrate comprising between 20x10 ⁶ and 10 ⁹ cells per milliliter to a light source, while performing setting, in movement of said concentrate, so as to place this chlorelle concentrate under stress to produce itself its metabolism, namely chlorelline, which will protect its concentration medium and thus prolong the duration during which chlorella loaded with chlorella may be consumed.

2 - A method of conservation according to claim 1, characterized in that it exposes the concentrate (24) to the light source (10) periodically.

3 - The method of conservation according to any one of the preceding claims, characterized in that it comprises an additional step consisting of an addition of nitrogen supplement NPK in the concentrate (24).

4 - A method of conservation according to any one of the preceding claims, characterized in that it implements a concentrate (24) or chlorelle, to produce useful elements comprising chlorelin or odontella or spirulina .

5 - Device for producing chlorellin from harvested chlorella, characterized in that it comprises means implementing a process of. production according to any one of the preceding claims. 6 - Production device according to claim 5, characterized in that it comprises a reactor (20, 40) having transparent walls, using a light source (10) which is indifferently then located outside or inside said reactor.

7 - Production device according to claim 6, characterized in that the reactor is in the form of a transparent tube (40) arranged vertically.

8 - Production device according to any one of claims 6 and 7, characterized in that the light source (10), inside or outside said device, comprises LED light emitting diodes having a light spectrum corresponding to solar radiation.

9- Production device according to any one of claims 6 to 8, characterized in that it comprises a movable mechanical system (26) or an air bubble injection device (28) adapted to perform the movement at within the concentrate (24).