A method for growing microalgae biomass and an installation for its implementation

Abstract

The inventions relate to biotechnology, and more particularly to a process and equipment for cultivating and producing a biomass from microalgae, primarily plankton. The essence of the group of inventions consists in that a microalgal biomass is cultivated in a single bioreactor chamber in the shape of a vertically oriented parallelepiped, the culture mixture is illuminated by artificial light sources mounted on the inner side of one of the broad walls of the bioreactor chamber in horizontal rows throughout the height of the bioreactor chamber, and spray heads are mounted on the inner side of the opposite wall of the bioreactor chamber so that 4 spray heads are arranged symmetrically around each artificial light source. The culture mixture is illuminated cyclically, wherein the pH value of the culture mixture is maintained in a range of 8.5-9.5 throughout all of the cycles by adding a solution containing lactic acid bacteria to the culture mixture at the beginning of each light cycle, said solution having a pH value selected in a range of 3.5-4.0 and being added in an amount of 1-3 ml per litre of culture mixture. The group of inventions makes it possible to produce a finished product in 48 hours, 1 litre of which contains from 7 to 10 grams of raw microalgal mass.

Description

[0001] METHOD FOR CULTIVATING MICROALGAE BIOMASS AND AN INSTALLATION FOR ITS IMPLEMENTATION

[0002] Field of technology

[0003] The group of inventions relates to biotechnology, namely to the technology and equipment for the process of cultivating the biomass of microalgae, primarily planktonic, such as chlorella, and can be used in enterprises of the microbiological and pharmaceutical industries.

[0004] State of the art

[0005] Microalgae biotechnology arose from research related to three different fields: space, submarines, and bomb shelters. This research was aimed at developing closed-loop life support systems. Such systems can be used in environments where there is no escape for carbon dioxide generated by human activity, as well as in areas where food sources in the form of protein, carbohydrates, and lipids are required. Microalgae biotechnology utilizes a fundamental property of plants—the ability of photosynthetic cells to fix CO2 from the atmosphere and convert it into various substances (biomass), releasing oxygen into the atmosphere. Since microalgae contain a full range of micro- and macronutrients, including all essential amino acids, vitamins B1, B2, and B б , and B 12, magnesium, iron, zinc, healthy fats and vitamin A (beta-carotene), their use allows us to maintain the vital activity of living beings at the molecular level.

[0006] A method is known for obtaining microalgae biomass, in particular, a chlorella suspension, in which the nutrient medium and the initial culture of chlorella strains are poured into a bioreactor in the form of a container made of a transparent material, the culture liquid is illuminated using an artificial light source while maintaining the required temperature of the culture liquid in the bioreactor, and the chlorella biomass is removed as a target product (patent for invention RU 2176667, IPC C12N 1 / 12, C12M 3 / 00, published 12 / 10 / 2001).

[0007] The described method is implemented in a setup consisting of containers made of transparent material illuminated by an artificial light source. The containers are spaced apart on a frame tray around the light source, with the light source mounted on the frame and capable of vertical movement toward the tray.

[0008] On the first day of chlorella cultivation, the light source is positioned in the highest position. On the second day, it is lowered to 2 / 3 of the tray, and on the third day, to 1 / 3 of the tray. The light source remains in this position until the end of the cultivation process, ensuring optimal illumination and suspension temperature throughout the entire process. The daily illumination duration during microalgae cultivation ranges from 20 to 22 hours.

[0009] The main disadvantages of the known method, implemented in the known device, are low productivity and low quality of the finished product, which does not allow the use of this method and device in the food industry.

[0010] A known method for the continuous production of planktonic algae, primarily food chlorella, includes preparing a mineral nutrient medium, adding an initial culture of a microalgae strain, pouring the resulting culture mixture into bioreactors made in the form of chambers made of light-transmitting material, illuminating the culture mixture using vertically installed artificial light sources, removing the resulting suspension into a collection container, removing the resulting sedimented biomass as a target product (patent for invention RU 2571939, IPC C12M 1 / 00, C12M 3 / 02, C12N 1 / 12, 3 / 02, A01G 33 / 00, published 27.12.2015). The known method can be implemented in an installation containing two chambers for the suspension, lamps, containers for preparing the nutrient solution and for collecting and storing the finished suspension, connected to the chambers by pipelines, located on a frame.Both microalgae suspension chambers are mounted on a frame with adjustable spacing and connected at the bottom of the vertical walls by a pipeline to equalize the suspension volume in both chambers. Each suspension chamber has two drain holes, one located at the bottom of the side wall for draining the prepared chlorella suspension and transporting it via a pipeline to a suspension collection and storage tank, and the second hole located in the lower plane. One of the suspension chambers is designed to grow stock cultures and support a unified biotechnological process. The lamps in each chamber are positioned eccentrically relative to its longitudinal axis. The lamp located between the chambers is mounted on a separate frame, independent of the frame and chambers, and can be freely moved and removed when switching to sunlight.The tank for the nutrient solution is located at a level above the chambers and has two openings made in the vertical side wall, the first of which is located at a level of 0.5 of the volume, and the second - in the bottom layer with the possibility of connecting pipes to them for draining the nutrient solution into the aquariums.

[0011] The disadvantages of the known method for the continuous production of planktonic microalgae and the installation for its implementation also include the low quality of the finished product and low specific productivity, which does not allow the use of the known method and device in the food industry.

[0012] A method is known for obtaining microalgae biomass, in particular, a suspension of food-grade chlorella, which includes growing chlorella in an automatic bioreactor made of a transparent material while illuminating the culture mixture using artificial light sources for 4 light cycles, each of which includes 10 hours of illumination and the subsequent 2 hours of no illumination, during the illumination period the temperature of the culture mixture is maintained in the range of 26-30 ° C, and during the period of no illumination - in the range of 24-26 ° C, removing the resulting suspension into a container for natural sedimentation for 30 days (patent for invention RU 2662974, IPC C12N 1 / 12, C12M 3 / 00, C12M 1 / 00, 3 / 02, C12R1 / 89, published 31.07.2018).

[0013] Despite the fact that the implementation of the known method allows for an increase in the quality of the finished product in comparison with the above-described methods known from the prior art, in practice it is not possible to achieve such specific productivity indicators that could ensure the effective use of this method in the food industry.

[0014] The closest analogue to the claimed group of inventions is the invention disclosed in patent RU 2540011 (IPC C12M 1 / 00, C12M 3 / 02, A01G 33 / 00, published 01 / 27 / 2015).

[0015] The patent discloses a chlorella cultivation system comprising a system of chlorella bioreactors, each consisting of horizontally oriented chambers made of transparent material equipped with mixing devices and connected to a finished suspension tank via a discharge line. A carbon dioxide solution bioreactor is connected at the outlet to the chlorella bioreactors. A nutrient solution preparation station is connected at the outlet to the chlorella bioreactors and the carbon dioxide solution bioreactor. Pumps and shut-off and control devices are also included. Lighting fixtures, shaped like light bulbs, are equipped with a cooling system and are installed inside the chlorella bioreactor housings. Stationary cleaning heads are also located inside the chlorella bioreactor housings, connected at the inlets to a cleaning fluid preparation system.The devices that provide the processes of mixing, regulation, washing and drainage are placed and connected under the chlorella bioreactors, while the bioreactors are equipped with lines for draining the washing liquid into the drainage and are connected at the inlet to the tank of the finished suspension.

[0016] The microalgae cultivation method is implemented as follows. Water is pre-treated to remove unwanted impurities. The purified and heated water is then fed to a nutrient solution preparation station, which is used in microalgae cultivation in chlorella bioreactors and in carbon dioxide production in the lactic acid bacteria bioreactor. The nutrient solution for the lactic acid bacteria bioreactor is supplied by a pump and regulated by a flow meter and controller. The nutrient solution for algae suspension production in the chlorella bioreactors is supplied via a pressure line, also by a pump, through a solenoid valve controlled by the controller. The algae stock culture is supplied from the prepared suspension tank by a pump through a corresponding solenoid valve.The CO2 solution is supplied using a CO2 pump from the lactic acid bacteria bioreactor to the chlorella bioreactors through a solenoid valve that supplies the lactic acid bacteria solution to the chlorella bioreactors. This valve is regulated by a flow meter and controller. Illumination of the chlorella bioreactor chambers is provided by artificial light sources installed vertically inside the chamber housings. The lighting timing and cycle are regulated by a controller. The lamps simultaneously provide illumination and maintain the microclimate in the algae suspension. After the finished product is obtained, the chlorella bioreactors are emptied through a finished product drain valve using a pump into the finished suspension tank. The bioreactor chambers are then cleaned using a system of cleaning heads.The washing heads are fed by a pumping station with a system for preparing washing liquid for chlorella bioreactors; drainage of the bioreactor chambers is carried out through a ball valve.

[0017] The chlorella cultivation system and method described in patent RU 2540011 also have a number of drawbacks. Specifically, the implementation of the inventions in this patent does not allow for high specific productivity, primarily due to the system's large footprint due to the horizontally oriented bioreactor chambers, long breaks between chlorella cultivation cycles, and inconvenient maintenance.

[0018] The described known methods for producing food-grade chlorella and the associated installations offer certain advantages over methods and installations based on surface illumination of the feed solution. However, all known microalgae production methods and installations, including their closest analogues, have significant drawbacks. These primarily include the insufficient efficiency of the processes in the bioreactor chamber, the significant space required, and the high cost per unit of finished product. Furthermore, the limited throughput of the installation is due to the need for interruptions to clean the lamps used as light sources, as well as the inconvenience of maintenance.

[0019] Disclosure of invention

[0020] The technical problem solved by the claimed inventions of the group is the creation of a method and a device for implementing this method that would make it possible to obtain a high-quality microalgae suspension while ensuring high specific productivity.

[0021] The claimed group of inventions, unlike existing technical solutions, solves the problem by organizing an optimal process flow regime to increase the specific productivity of the plant, reduce the required production space, and improve ease of maintenance. This regime is achieved through the development of an efficient microalgae cultivation process and a fundamentally new hardware design for the plant.

[0022] The stated technical solutions (method and device) are aimed at solving the stated problem and achieving a technical result consisting of improving the quality of the finished product and specific productivity, as well as reducing material consumption.

[0023] In terms of the method, the claimed technical result is achieved due to the fact that in the method for producing microalgae, in particular, a suspension of food-grade chlorella, in which a nutrient medium containing the elements N, P, Fe, Cu, Co and the initial culture of chlorella strains are poured into a bioreactor made in the form of a container made of a transparent material, illuminating the culture liquid with an artificial light source of the culture liquid while maintaining the required temperature of the liquid in the bioreactor and using carbon dioxide as carbon nutrition, obtained organically through the process of metabolism of lactic acid bacteria, removing chlorella biomass as the target product, a prepared mineral nutrient medium of the following composition is used: ammonium nitrate (34% solution) - 0.14 ml ammophos (15% solution) - 0.10 ml iron chloride (1% solution) - 0.15 ml cobalt nitrate (0.1% solution) - 0.10 ml copper sulfate (0.1% solution) - 0,10 ml drinking water - 1000 ml;

[0024] - biomass cultivation is carried out in a single chamber, made in the form of a vertically oriented parallelepiped,

[0025] - the illumination of the culture mixture is carried out by artificial light sources installed on the inside of one of the wide walls of the bioreactor chamber in horizontally oriented rows along the height of the bioreactor chamber,

[0026] - the illumination of the culture mixture is carried out cyclically,

[0027] - throughout all microalgae cultivation cycles, the pH value of the culture mixture is maintained in the range of 8.5-9.5 by adding a solution with lactic acid bacteria to the culture mixture at the beginning of each light cycle, the pH value of which is selected in the range of 3.5-4.0, in an amount of 1-3 ml per 1 liter of the culture mixture.

[0028] The claimed technical result is achieved through the entire set of essential features given in independent clause 1 of the formula of the invention, characterizing the object “method”.

[0029] The use of a mineral nutrient medium of a given composition for growing microalgae, containing 0.14 ml of ammonium nitrate (34% solution), 0.10 ml of ammophos (15% solution), 0.15 ml of iron chloride (1% solution), 0.10 ml of cobalt nitrate (0.1% solution), 0.10 ml of copper sulfate (0.1% solution) in 1000 ml of purified drinking water, in combination with cyclic illumination of the culture mixture, the pH value of which is maintained in the range of 8.5 -9.5 throughout all microalgae cultivation cycles by adding to the culture mixture at the beginning of each light cycle a solution with lactic acid bacteria, the pH value of which is selected in the range of 3.5 - 4.0, in an amount of 1-3 ml per 1 l of the culture mixture, makes it possible to provide the most favorable conditions for the growth of microalgae and thereby improve the quality characteristics of the finished product and the specific productivity.

[0030] This combination of essential features allows us to obtain a high-quality finished product based on the Chlorella vulgaris strain, in particular, a drink with live chlorella, Detox Urban Drink, which contains only live chlorella cells of the Chlorella Vulgaris GKO strain that have not been subjected to heat treatment, a nutrient solution in which they grew, consisting of lactic acid bacteria (Lactobacillus), chlorella metabolites (useful substances that chlorella produces as it grows) and the purest artesian water that has undergone a special multi-stage preparation.

[0031] According to Wessling Laboratory research into the composition of Detox Urban Drink, a live chlorella drink produced using the Chlorella vulgaris GKO strain, it contains 13 vitamins and 12 different minerals essential for the human body. The drink's amino acid profile contains 18 components, and its fatty acid profile contains 12. Many of these elements also act as antioxidants.

[0032] Detox Urban Drink contains the following fatty acids: arachidonic (omega-6), linoleic (omega-6), docosahexaenoic (omega-3), alpha-linolenic (omega-3), linoleic, palmitic, oleic (omega-9), palmitoleic, stearic, myristic, pantadecanoic and erucic.

[0033] Detox Urban Drink contains antioxidants from the carotenoid group (beta-carotene), polyphenols - lutein, catechin, epicatechin, epigallocatechin gallate, quercetin, vitamins A, E and C, as well as antioxidant minerals - selenium, copper, zinc, manganese.

[0034] Maintaining the specified pH values ​​of the culture mixture and the lactic acid bacteria (Lactobacillus) solution during microalgae cultivation ensures the viability of microalgae cells and the preservation of their beneficial properties. Failure to comply with the cultivation conditions leads to the degeneration of the algae monoculture or contamination with weed bacteria, which directly leads to the loss of the functional properties of the finished product. The closed-loop microalgae cultivation process eliminates the risk of contaminants and pathogens entering the bioreactors. However, even a short-term disruption to the parameters during the production cycle can lead to serious problems, as each chlorella cell, dividing twice daily, is subject to natural mutations, and its environment is a breeding ground for a wide range of weed bacteria.

[0035] The claimed method according to dependent claim 2 of the invention may be supplemented by the fact that the illumination of the culture fluid is carried out in an automatic bioreactor over four consecutive cycles, each of which includes 10 hours of illumination, followed by a 2-hour break in illumination with the artificial light sources turned off. During the illumination period, the temperature in the bioreactor is maintained at 26-30°C, and during the period without illumination, at 24-26°C. Illumination of the culture mixture in the specified mode allows for the creation of the most optimal conditions for the intensive growth and reproduction of microalgae cells. When implementing this mode, the optical density of the microalgae culture solution reaches values ​​of (1.4-1.8) D (standard optical density). Moreover, the entire process is carried out in compliance with the sanitary requirements that must be ensured in the production of food products.

[0036] A shift in the temperature regime in one direction or another leads to mutation processes in microalgae cells and, as a consequence, to a decrease in the quality of the finished product and specific productivity.

[0037] Illumination of the culture fluid during four consecutive cycles, as defined in dependent claim 2 of the invention, has an additional effect on improving the quality of the resulting microalgae suspension and specific productivity. We have previously used this illumination regime (patent RU 2662974). However, using this regime in combination with the techniques of the claimed method allows us to create the most optimal conditions for the microalgae cultivation process, which in turn ensures higher process performance.

[0038] The claimed method according to paragraph 3 of the formula of the invention can be supplemented by the fact that the pouring of the culture mixture into the bioreactor chamber is carried out above the level of any horizontal row of light sources by an amount equal to half of their interaxial distance in height.

[0039] The feasibility of implementing the invention according to dependent claim 3 of the invention formula allows for varying the filling volume of the bioreactor chamber to obtain specified quantities of finished product. Pouring the culture mixture into the bioreactor chamber above the level of any horizontal row of light sources by a distance equal to half their vertical center-to-center spacing allows for varying the working volume of the bioreactor chamber to obtain the desired quantity of finished product while ensuring high specific productivity and high product quality.

[0040] In the part of the device, the claimed technical result is achieved due to the fact that in the installation for growing microalgae biomass, containing sequentially placed bioreactors made in the form of horizontal chambers made of transparent material, equipped with mixing means, connected by a discharge line to a container of finished microalgae biomass, a bioreactor of a solution of lactic acid bacteria, connected at the outlet with the microalgae bioreactors, a unit for preparing a nutrient medium, connected at the outlet with the microalgae bioreactors and the bioreactor of a solution of lactic acid bacteria, artificial light sources in the form of electric lamps equipped with a cooling system, washing heads connected to a system for preparing a washing liquid, pumps and shut-off and control devices, the chamber of the microalgae bioreactor is made in the form of a vertically oriented parallelepiped made of transparent material,artificial light sources are installed on the inside of one of the wide walls of the chamber perpendicular to it in horizontally oriented n rows along the height of the chamber, washing heads are installed on the inside of the opposite wall of the bioreactor chamber in such a way that 4 washing heads are symmetrically placed around each artificial light source.

[0041] The claimed technical result is achieved through the entire set of essential features given in independent clause 4 of the invention formula characterizing the object “device”.

[0042] The design of the bioreactor chamber in the form of a single vertically oriented parallelepiped with artificial light sources installed on the inside of one of the wide sides of the chamber in horizontally oriented rows along the height of the chamber, as well as the placement of washing heads on the inside of the opposite wall of the bioreactor chamber in such a way that 4 washing heads are symmetrically placed around each artificial light source, allows for the optimization of the design of the installation itself in such a way that this, in turn, leads to the creation of an optimal organization of the ongoing processes of microalgae cultivation, ensuring the production of high-quality finished products with high specific productivity while minimizing material consumption, occupied space and increasing ease of maintenance.The chamber's construction in the form of a vertically oriented parallelepiped, with several horizontal rows of artificial light sources placed on one of its wide walls, not only minimizes the space occupied by the installation, i.e., ultimately increases specific productivity, but also makes it possible to produce different specified quantities of finished product in the same chamber, depending on its filling level.

[0043] The claimed invention according to dependent claim 5 of the formula of the invention may be supplemented by the fact that the installation is equipped with a programmable automatic system for monitoring and controlling the set parameters of temperature, volume, dosage, loading, unloading of the solution and the finished product.

[0044] The installation for implementing the claimed method according to dependent claim 6 of the invention may comprise two or more bioreactors. This installation configuration allows for a significant increase in the volume of high-quality finished product, compared to known solutions.

[0045] In general, the claimed group of inventions makes it possible to increase the productivity and quality of the finished product, as well as the ease of use, operational safety, and efficiency of the lamp cooling system through the effective hardware design of the installation, which makes it possible to ensure the process of producing a microalgae suspension in an automatic mode, while practically eliminating the need for manual labor to ensure the operability of the installation.

[0046] Brief description of the drawings

[0047] The essence of the claimed group of inventions is explained by the drawings (Fig. 1 - Fig. 3). Fig. 1 shows a longitudinal section of the general view of the installation, Fig. 2 - a cross-section of the bioreactor chamber, Fig. 3 - a section of the bioreactor chamber in plan.

[0048] In accordance with the presented drawings (Fig. 1 - Fig. 3), the installation contains:

[0049] 1 - bioreactor chamber,

[0050] 2 - bioreactor of a solution with lactic acid bacteria,

[0051] 3 - instrumentation and automation panel, 4 - control controller,

[0052] 5 - submersible lamp, where

[0053] 5.1 - electric lamp,

[0054] 5.2 - lamp housing with flow channel,

[0055] 6 - washing heads,

[0056] 7 - electromagnetic valves for controlling washing heads,

[0057] 8 - electromagnetic valve for feeding mother culture / nutrient medium,

[0058] 9 - peristaltic pump for dispensing a solution of lactic acid bacteria,

[0059] 10 - motorized drain valve,

[0060] 11 - motorized tap for draining the finished product,

[0061] 12 - pump for prepared feed water,

[0062] 13 - a pumping station with a system for preparing washing liquid,

[0063] 14 - mother culture pump,

[0064] 15 - finished product pump,

[0065] 16 - circulation pump for the lamp cooling system,

[0066] 17 - instantaneous water heater,

[0067] 18 - nutrient medium flow meter,

[0068] 19 - nutrient solution preparation station,

[0069] 20 - capacity of the finished product,

[0070] 21 - level converter in the bioreactor,

[0071] 22 - three-way motorized control valve for the cooling circuit of lamps,

[0072] 23 - heat exchanger for the lamp cooling circuit.

[0073] Implementation of the invention

[0074] The developed method is implemented in the installation of the declared design.

[0075] The installation works as follows.

[0076] The unit is housed in a translucent room, providing additional illumination or complete solar illumination of the algae suspension. An air conditioning system is used without the addition of atmospheric air. Devices for dosing, lighting, mixing, measuring, regulation, washing, drainage, and emptying are housed in a separate instrumentation and automation panel (3). Feedwater, pre-treated to remove unwanted impurities, is fed by pump (12) to direct-flow water heater (17), then to nutrient solution preparation station (19). During these steps, a nutrient solution is prepared, which is divided into two production lines and used in the microalgae suspension cultivation process in the bioreactor, as well as in the production of lactic acid bacteria solution in lactic acid bacteria solution bioreactor (2).

[0077] The nutrient solution for the bioreactor with lactic acid bacteria 2 is supplied by pump 12 and is regulated by flow meter 18 and controller 4. The nutrient solution for producing the algae suspension in the bioreactor is supplied via the pressure line also by pump 12 through electromagnetic valve 8 controlled by controller 4. The filling level of the nutrient medium in the bioreactor is regulated by level converter 21 and controller 4 installed in panel 3. The supply of the microalgae mother culture is carried out from the tank of the finished suspension 20 by pump 14 through electromagnetic valve for filling the mother culture 8 and is regulated according to the principle of supplying the nutrient medium. The supply dosage of the solution with lactic acid bacteria is carried out by dosing pump 9 with a fixed capacity from the bioreactor with lactic acid bacteria 2 to bioreactor 1 and is regulated by the dosing time by controller 4 installed in panel 3.Illumination of bioreactor 1 is provided by luminaires 5 with a liquid-cooled jacket installed within the housings. Each luminaire is designed as a light bulb 5.1, equipped with an additional casing 5.2 made of transparent material, enveloping the housing of light bulb 5.1 to form a flow channel, the inlet and outlet of which are interconnected via cooling system heat exchanger 23, a coolant supply line, and a coolant outlet line. Coolant circulation is provided by pump 16 and regulated by three-way motorized valve-regulator 22. The duration and cyclical illumination of the nutrient medium are regulated by controller 4, installed in panel 3. Luminaires 5 simultaneously provide illumination and maintain the microclimate in the microalgae suspension.After receiving the finished product, the bioreactor 1 is emptied through a motorized finished product drain ball valve 11 using a pump 15 into a finished suspension tank 20, after which the sections are washed using a system of washing heads 6. The heads are fed by a pump station 13 with a system for preparing washing liquid for chlorella bioreactors; the bioreactor chamber is drained through a motorized ball valve 10.

[0078] Installing a system of stationary cleaning heads connected at the inlets to the cleaning fluid preparation system inside the bioreactor chamber and supplying the bioreactor with a cleaning fluid drainage line allows for automatic cleaning and removal of contaminants from the bioreactor chamber and light fittings without the need for manual labor. Placing the cleaning heads on the inner wall of the bioreactor chamber, opposite the wall housing the light sources, with four cleaning heads symmetrically positioned around each light source, ensures that the light source surface is washed almost completely. This placement of the cleaning heads and the organization of an optimal cleaning algorithm for bioreactor zones 1 using electromagnetic valves 7 not only reduces the time spent cleaning the light sources but also eliminates the possibility of contamination of the bioreactor chamber with unwanted bacteria.

[0079] The above solutions allow to increase the productivity of the plant and the quality of the target product by eliminating the infection of the culture with spores of other algae.

[0080] The best example of the method implementation

[0081] The claimed method for obtaining a suspension of microalgae, in particular food-grade chlorella, is carried out as follows.

[0082] A nutrient medium is prepared in advance using programmable dosing pumps. The nutrient medium contains the following elements: N, P, Fe, Cu, Co; per 1000 ml of water it contains 0.14 ml of ammonium nitrate (34% solution), 0.10 ml of ammophos (15% solution), 0.15 ml of ferric chloride (1% solution), 0.10 ml of cobalt nitrate (0.1% solution), 0.10 ml of copper sulfate (0.1% solution).

[0083] The bioreactor chamber is then filled with the initial chlorella suspension to the required volume, and the required volume of nutrient medium of the above composition is added. Illumination of the culture fluid is carried out in an automated bioreactor for four consecutive cycles, each consisting of 10 hours of illumination, followed by a 2-hour break in illumination with the artificial light sources turned off. During the illumination period, the bioreactor temperature is maintained at 26-30°C, and during the absence of illumination, at 24-2°C. This corresponds to developmental biology and promotes intensive growth and reproduction of chlorella cells. With this cultivation, the culture achieves an optical density of 1.4-1.8 D (440) (standard optical density). Cultivation is carried out in compliance with strict food safety regulations.

[0084] The resulting suspension is poured from the bioreactor into a container for the finished suspension, in which natural sedimentation of chlorella occurs for 30 days using natural diffused light, that is, under normal lighting without the use of artificial light sources.

[0085] After completion of the microalgae cultivation cycles, the light sources are washed and the cleaning liquid is discharged into the drainage system.

[0086] All processes of washing, drainage of washing liquid, filling the bioreactor chamber with mother culture, nutrient medium, control of lighting cycles, maintaining the temperature regime, dosing of carbon dioxide solution, and cyclic mixing are carried out by automatic devices under the control of a programmable controller.

[0087] The resulting suspension is poured from the bioreactor into a container for natural sedimentation of food-grade chlorella with a body made of transparent material, and natural sedimentation of chlorella is carried out for 30 days using natural diffused light, that is, under normal lighting without the use of artificial light sources.

[0088] The best embodiment of the claimed group of inventions, when applied at an optical density of 1.4 to 1.8 D, allows for the production of a finished product within 48 hours. One liter of the product contains 7 to 10 grams of wet microalgae mass, ensuring a high-quality finished product. Known microalgae cultivation methods yield 3 to 5 g / L.

[0089] The claimed method for cultivating microalgae biomass allows for the production of a high-quality finished product in the claimed device, which can be used in the food, microbiological and pharmaceutical industries.

Claims

CLAUSES OF THE INVENTION 1. A method for growing microalgae biomass, which includes preparing a mineral nutrient medium, adding an initial culture of a microalgae strain, pouring the resulting culture mixture into a system of sequentially arranged bioreactors made in the form of horizontally oriented chambers made of light-transmitting material, illuminating the culture mixture using vertically installed artificial light sources, removing the resulting suspension into a container for natural sedimentation and subsequently removing the resulting sedimented biomass as the target product, characterized in that - the prepared mineral nutrient medium has the following composition: ammonium nitrate (34% solution) 0.14 ml ammophos (15% solution) 0.10 ml iron chloride (1% solution) 0.15 ml cobalt nitrate (0.1% solution) 0.10 ml copper sulfate (0.1% solution) 0.10 ml drinking water 1000 ml, - biomass cultivation is carried out in a single chamber of a bioreactor, made in the form of a vertically oriented parallelepiped, - the illumination of the culture mixture is carried out by artificial light sources installed on the inside of one of the wide walls of the bioreactor chamber in horizontally oriented rows along the height of the bioreactor chamber, - the illumination of the culture mixture is carried out cyclically, - throughout all microalgae cultivation cycles, the pH value of the culture mixture is maintained in the range of 8.5-9.5 by adding to the culture mixture at the beginning of each light cycle a solution with lactic acid bacteria, the pH value of which is selected in the range of 4.0-5.0, in an amount of 1-3 ml per 1 l of the culture mixture.

2. The method according to paragraph 1, characterized in that the illumination of the culture mixture is carried out during 4 light cycles, each of which includes 10 hours of illumination and the subsequent 2 hours of no illumination, during the illumination period the temperature of the culture mixture is maintained in the range of 26-30°C, and during the no illumination period - in the range of 24-26°C.

3. The method according to paragraphs 1 and 2, characterized in that the pouring of the culture mixture into the bioreactor chamber is carried out above the level of any horizontal row of light sources by an amount equal to half of their interaxial distance in height.

4. A plant for growing microalgae biomass, comprising sequentially placed bioreactors made in the form of horizontal chambers made of transparent material, equipped with mixing means, connected by a discharge line to a tank of finished microalgae biomass, a bioreactor of a solution with lactic acid bacteria, connected at the outlet to the microalgae bioreactors, a unit for preparing a nutrient medium, connected at the outlet to the microalgae bioreactors and the bioreactor of a solution with lactic acid bacteria, artificial light sources in the form of electric lamps equipped with a cooling system, washing heads connected to a system for preparing a washing liquid, pumps and shut-off and control devices, characterized in that the chamber of the microalgae bioreactor is made in the form of a vertically oriented parallelepiped made of transparent material, - artificial light sources are installed on the inside of one of the wide walls of the chamber perpendicular to it in horizontally oriented n rows along the height of the chamber, - washing heads are installed on the inside of the opposite wall of the bioreactor chamber in such a way that 4 washing heads are symmetrically placed around each artificial light source.

5. The installation according to item 4, characterized in that it is equipped with a programmable automatic system for monitoring and controlling the set parameters of temperature, volume, dosage, loading, unloading of the solution and the finished product.

6. The installation according to paragraph 4, characterized in that it contains two or more bioreactors.

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