FR3138147A1 - NEW PHOTO-BIOREACTOR AND AUTOMATED CULTURE SYSTEM - Google Patents

Abstract

The present invention relates to a photo-bioreactor device optimized to provide total control of a light source of said variable intensity device, said intensity being controlled by means of analog regulation of an LED light source powered by a direct current, and being supplemented where necessary by digital regulation to integrate a flash function. The device of the invention also comprises an internal light source incorporating a cleaning mechanism and being designed to facilitate its maintenance. The invention also relates to an automated cultivation system making it possible to obtain a high yield of biomass production, and to precisely monitor cultivation conditions.

Description

NEW PHOTO-BIOREACTOR AND AUTOMATED CULTURE SYSTEM Field of the invention

The present invention relates to the field of photo-bioreactors for the cultivation of photosynthetic microorganisms such as microalgae, and automated cultivation processes. The invention relates in particular to the regulation and optimal configuration of the lighting of a photo-bioreactor and the design of an automated microalgae cultivation system.

Technology background

Today, there are many types of PBR photobioreactors for microalgae cultivation. Most of these devices are designed for laboratory use, and do not allow high-yield biomass production or precise control of lighting and cultivation conditions. In general, a photo-bioreactor comprises at least one open or closed tank to contain the culture medium and a light source making it possible to irradiate said tank. Access to light is one of the factors most limiting crop yields and different photo-bioreactor models have been proposed to optimize the tank surface area and illuminated volume ratio. On the other hand, lighting power also represents one of the largest costs of operating a PBR. It is therefore desirable to have a tank and a lighting configuration to illuminate the growing medium as best as possible, while limiting energy consumption. The use of LED light-emitting diodes as a light source has been proposed to meet this need.

For example, patent application US 2010/0190227 discloses a photo-bioreactor integrating a light source inside the tank, in particular in the form of an LED insert molded in plastic. The photo-bioreactor is designed in several modules, each module comprises a tank integrating an LED insert in the form of a vertical pipe, said insert being positioned on a lateral side of said module, offset from the central axis of the tank, and so that the opposite side of said module integrates an upper opening allowing a second module to be connected to said opening. This document proposes to increase the culture capacity of the photo-bioreactor by vertically stacking several modules communicating with each other through their upper openings, so as to alternate the orientations of the LED inserts on each floor to have a helical geometry for positioning said LEDs through of the column. This system is advantageous in that it makes it possible to integrate a light source inside the tank and reduce the energy consumption of the lighting. However, new photo-bioreactors are still needed to further optimize and control the lighting conditions of a PBR.

The present invention therefore aims to propose an improved photo-bioreactor to improve the use of light and the light/illuminated surface ratio.

Another objective is to offer a lighting system allowing perfect control of the lighting mode.

Another objective of the invention is to propose a photo-bioreactor adapted to any type of culture (mixotrophy, heterotrophy, batch, continuous or semi-continuous) and making it possible to precisely configure the culture conditions.

Another objective of the invention is to propose an automated microalgae cultivation system.

For these purposes, the invention proposes a photo-bioreactor device, said device comprising a culture tank, a light source with LED light-emitting diodes, a power regulation module of said light source and a control unit, characterized in that :

-the light source is configurable in light intensity, in time, and preferably in wavelength by means of said power regulation module controlled by said control unit, and

-the regulation module is powered by a direct current and implements analog regulation to control the power supply of the light source, varying the light intensity.

The device of the invention is very advantageous in that it allows the implementation of LED lighting which can be activated and controlled precisely to operate in a desired lighting mode, as well as to vary its light intensity. . In particular, the analog regulation of light intensity ensures true continuity of lighting when it must be active, while varying its intensity. It will therefore be possible to reliably study the effect of lighting mode and time on the growth of a culture or the production of a metabolite of interest. On the contrary, digital regulation to vary the intensity of the LED introduces false lighting which appears continuous to the human eye, but is composed of chopped light signals and can be felt by the microalgae.

In a preferred embodiment, the light source is configurable according to a flash lighting mode, and the device comprises a flash regulation module implementing digital regulation controlled by the control unit, such as PWM type, for activate and deactivate said light source at high intensity and speed. This lighting mode is very advantageous in that it allows energy savings, and the device of the invention makes it possible to provide a perfectly configurable flash effect.

In a preferred embodiment, in which the light source is configurable in wavelength and variably over an operating cycle, and the device comprises a power regulation module under analog control for each channel powering one or more LEDs of said light source.

In one embodiment, the light source comprises at least one light sensor in communication with said control unit, and the latter implements feedback control of a power supply control of the light source according to a luminous flux measured by said light sensor, and in which said reservoir preferably comprises one or more walls coated with a reflective layer arranged to reflect the light from said light source. It is thus possible to further control the light intensity and improve the use of light.

Preferably, said light source is integrated inside the culture tank in the form of a vertical light pipe integrating said LEDs, and the light source comprises a location column extending from a bottom of the culture tank and opening in a sealed manner at an upper closure of said culture tank, and in which the light pipes are housed inside said location column, and an upper opening of the location column is configured as an independent closable opening, and allowing the sealing of an internal volume of the culture tank to be maintained when it is opened. This mode of integration of the light source allows access and troubleshooting of the light source without the need to stop the culture in progress, and without compromising the sterility of the culture in the tank.

Advantageously, the device of the invention comprises a mechanism for cleaning an external wall of the light source in contact with the culture medium, said mechanism comprising a pair of magnets arranged on one side and the other of said outer wall of the light source, and being driven by a system of pulleys to move along the light source.

In particular, said pulley system, and an internal magnet of said pair of magnets can be arranged inside the hollow interior of the pipe of the light source, and the second magnet of said pair of magnets comprises a cleaning element in contact with the outer wall of the location column.

The device of the invention may also include one or all of the following characteristics, and in any technically operable combination:

- the culture tank comprises one or more additional light sensors, such as photoresistors configured to measure a light flux in different zones of an internal volume of said culture tank receiving culture medium;

- the culture tank is connected to an analysis tank integrating pH and nutrient sensors, and a device for measuring cell concentration, such as a turbidimeter;

- the control unit comprises a user interface and an application configured to display a set of measurements from the sensors of the device communicating with said control unit, and making it possible to configure the lighting mode of the light source;

- the device comprises a lower gas inlet, such as CO ₂ , said inlet being configured to inject gas towards the top of the culture tank, and preferably the device comprises means for sterilizing air and controlling the air injection rate and its CO2 rate;

- the culture tank integrates a plurality of internal light sources in the form of light pipes, each light pipe defining an illuminated zone inside the culture tank, and said device also comprises a gas bubbling network comprising positioned outlets outside of illuminated areas and acting as a means of mixing the culture medium.

The invention also relates to an automated cultivation system comprising a photo-bioreactor device comprising a cultivation tank, a mixing tank, a water storage tank, and a nutrient storage tank interconnected by a circuit of pipes , and comprising a control unit comprising a processor and a memory coupled to said processor, and instructions saved in the memory and executed by the processor to control the operating conditions of said culture system, characterized in that:

-the culture tank has an inlet connected to the mixing tank for its supply of culture medium, and

- the mixing tank comprises an inlet connected to the water storage tank, an inlet connected to the nutrient storage tank, mixing means, temperature adjustment means, and pH control means, and in that

-the system is configured to prepare the culture medium in the mixing tank at a programmable concentration, temperature and pH by means of said control unit, and

-the system comprises transfer means under control of the control unit (such as a pump and a flow meter or a solenoid valve) assigned to each of the tanks of the system to activate and control a volume of liquid or solid transferred between said tanks.

This configuration of the system makes it possible to supply the culture tank with a culture medium comprising a controlled concentration, pH, and temperature. For example, a culture already in progress in the PBR will not be stressed by the addition of new culture medium, the latter being able to be done at the same concentration, temperature and pH as the medium in the culture tank, or at least at similar conditions.

Likewise, this configuration allows the control unit to be programmed with automated culture programs with saved instructions to maintain or modify certain culture conditions in the culture tank. In particular, in this embodiment the culture tank is connected to an analysis tank in communication with the control unit and integrating pH sensors, at least one nutrient, and a concentration measuring device cellular, such as a turbidimeter. Thus, the control unit includes a program with saved instructions to activate the introduction of the culture medium contained in the mixing tank according to the parameters measured in the analysis tank, such as a cell concentration, a pH or a concentration of nutrients.

Preferably, the culture tank also comprises an inlet connected to at least one pH tank comprising a pH adjustment solution, and a CO ₂ inlet connected to a CO ₂ source, and the control unit comprises a program comprising saved instructions for regulating the pH in said culture tank by controlling the introduction of the pH and/or CO ₂ solution by activating transfer means assigned respectively to said CO ₂ source and pH tank. The pH regulation mode can be chosen by the user.

In one embodiment of the system, the culture tank comprises an outlet connected to a harvest tank, and transfer means under control of the control unit to transfer a volume of liquid contained in the culture tank to said tank harvesting, and in which the control unit comprises a cultivation program making it possible to define a time, a frequency and a volume of liquid to be extracted from said culture tank towards the harvesting tank and/or a volume of liquid to be injected in said culture tank from the mixing tank.

The system of the invention also allows automatic start-up of the system, including cleaning and sterilization cycle of the system components. To this end, the transfer means between the tanks are bidirectional and the control unit includes a rinsing program comprising saved instructions for activating transfer means assigned to the water storage tank and injecting a liquid into the tank mixing and rinsing a set of tanks of the culture system from said liquid injected into the mixing tank, by sequentially operating transfer means assigned to each of said tanks of the system in a preconfigured order, and to empty the injected liquid into the system from the algae harvesting tank.

Advantageously, a sterilizing product can be added to the water storage tank, or possibly to the mixing tank, and so that the rinsing cycle also ensures the sterilization of the system. Preferably, the control unit includes a dedicated sterilization cycle, in which a time for the sterilizing liquid to pass through each tank of the system is defined. In another embodiment, sterilization is carried out by injecting a gas or steam into the tanks and pipes of the system.

Additionally, the system includes a user interface for selecting a culture program with culture duration, volume, and frequency of volume injection and extraction of culture medium into and from the culture vessel, as well as 'displaying measurements from a set of temperature, pH light, cell concentration and nutrient sensors of said culture system. The interface can be physically connected to the control unit and/or be an application in a mobile terminal or computer.

Finally, the control unit also includes a communication module, and the system includes a remote server hosting a database, said database comprising operating programs of the cultivation system downloadable and executable by the control unit. Preferably, the communication module is also configured to transmit to said database data associated with monitoring of a current crop for its storage and private or public availability.

Other advantages, aims and particular characteristics of the present invention will emerge from the description which follows, given for explanatory and in no way limiting purposes, with reference to the appended drawings.

Presentation of figures

Illustrates a schematic representation of an automated culture system integrating a photo-bioreactor device according to the invention.

Schematically illustrates the power supply regulation and control of the light source of the photo-bioreactor device of the invention.

Schematically illustrates the control of a light source with configurable wavelength according to the invention.

Schematically illustrates an internal light source comprising a cleaning system according to the invention.

Schematically illustrates the extraction of the light pipe and part of the cleaning system of a source location column according to the invention.

[Fig. 6 Schematically illustrates a front view of a photo-bioreactor device integrating several light sources according to the invention.

Schematically illustrates a top view of a photo-bioreactor device according to the .

Illustrates an embodiment of the monitoring and control interface of the device of the invention.

Detailed description of embodiments of the invention

The aim of the present invention is to propose a new photo-bioreactor allowing optimal control of the supply of light, as well as optimal use of the latter. Another objective is that the photo-bioreactor allows an in-depth and precise study of culture parameters, while allowing easy and high-yield culture.

Another objective is for the photo-bioreactor to be suitable for continuous or semi-continuous automated cultivation of photosynthetic microorganisms, in particular microalgae.

To this end, the invention proposes a photo-bioreactor provided with a light source controlled by a control unit. There illustrates a culture system integrating a photo-bioreactor 100 according to the invention, also called device 100 for the cultivation of photosynthetic microorganisms and comprising a culture tank C4 having the shape of a vertical column. The tank C4 defines an internal volume for the cultivation of said microorganisms and its shape is not limited and can have a circular or polygonal section, such as square.

Light source 2 is configurable in intensity, wavelength, time and lighting mode and according to the parameters desired by a user. The programmable lighting modes can be i) continuous, the light source is activated for an indefinite time, ii) intermittent, the light source is activated and deactivated according to fixed or variable activity and inactivity cycles, and iii) flash, the light source is activated at high intensity for a predefined duration and frequency. The photo bioreactor will thus make it possible to study the effect of the lighting mode precisely and to control it in order to obtain the best yields of biomass or production of a molecule of interest, or to optimize the consumption of 'energy. For example, it has been recognized in the scientific literature that the high intensity flash illumination mode makes it possible to obtain more than 50% reduction in energy consumption. Likewise, flash mode can have an effect on growth kinetics and cellular metabolism.

Advantageously, the invention proposes to control the intensity of the light source 2 by means of continuous type analog regulation ( ). This type of regulation ensures a luminous flux that does not vary its voltage in frequency, and therefore truly continuous. This is particularly important with the use of LEDs, the latter being traditionally controlled in power by a digital PWM modulation of binary type with frequency, and which is reflected in the chopping of the signal. That is to say, with PWM regulation the light signal is discontinuous, and formed by flashes of light not visible to the human eye. Microalgae are, however, capable of harvesting light on the order of picoseconds, and are therefore sensitive to these flashes of light invisible to the human eye.

So that the micro algae can access continuous light of constant intensity, the invention proposes to power the light source with a direct current ( ), and controlled by the control unit according to analog power regulation varying the lighting intensity.

There schematically illustrates the processing of the analog current by the power regulation module controlled by the central unit 1 for controlling the light source 2. In particular, the central unit controls the adjustment of the lighting power by means of 'analog regulation, allowing a continuous light signal to be maintained. The flash lighting mode is then activated by means of preferably a flash regulation module, preferably dedicated, and by generic digital regulation of the PWM type. For example, analog power regulation can be implemented using the RCD-24-1.20 driver, or using a Mosfet transistor such as the IRLZ34NPBF accompanied by one or more resistors. This last component can also be used as a flash regulation module. Preferably, a power control module is also integrated upstream of the light source 2, allowing verification of the power supplied to said light source. Whatever the embodiment, the light intensity is controlled by analog regulation and the flash mode is controlled by digital control.

Preferably, the device of the invention includes a light intensity feedback function making it possible to correct the luminous flux input in real time. In particular, the light source integrates a light sensor configured to transmit to the control unit the light intensity detected in operating conditions, and so that the control unit modifies a power command of the regulation module to that the light intensity illuminated at a time t is equal to the configured light intensity. Indeed, the light intensity provided by an LED is variable at the same power supply depending on the ambient temperature. An increase in temperature thus results in a reduction in the quantity of luminous flux provided by an LED. The colors from amber to red called “AlGalnP” provided by aluminum gallium indium phosphide LEDs are the most sensitive to this reduction in luminous flux, and the colors ranging from blue to green and white (based on “InGaN” ) are the least sensitive. Consequently, feedback control of the light flux supply is very advantageous for crops programmed with wavelengths sensitive to this phenomenon, or with programmed variations in wavelengths.

In a preferred embodiment, the lighting source is configurable in wavelength by means of multichannel LEDs, such as RGB LEDs making it possible to adjust a wavelength according to the wave supply of each channel . In this embodiment, the invention proposes to implement a power regulator module for each channel to be supplied with LED lighting and so as to be able to configure all the channels and create a tailor-made emission spectrum, in particular with a specific frequency and duty cycle. A flash regulation module and a power control module are also integrated for each channel to be controlled. It is thus possible to control the intensity and a flash lighting mode of each programmed wavelength. In another alternative embodiment not illustrated, a single flash regulation module is used placed upstream of the power regulation modules, thus making it possible to limit the number of total components. This last embodiment is suitable when the same flash signal is used for all LED channels.

In order to optimize the use of light, the invention also proposes to coat an internal surface of the culture tank C4 with a light-reflecting layer, so that the light not absorbed by the culture medium is directed again towards the culture medium. Preferably, this reflective layer is present on the entire vertical internal wall of the tank, or at least on a part and so as to leave one or more windows to visualize the interior of the culture tank.

According to the illustrated embodiment, the device 100 integrates the light source 2 inside the culture tank C4 in the form of a light pipe emitting light at 360°, and extending along an axis central and longitudinal of the culture tank C4. In another embodiment, the lighting source can be located outside the culture tank C4. The light source ( ) is composed of a transparent pipe 21 having a hollow interior integrating luminous elements 22 such as LED light-emitting diodes arranged around a wall of said pipe. These light elements are for example integrated in the form of a helical winding or in the form of vertical ribbons.

The invention also provides a cleaning system suitable for use with an internal light source. As illustrated in , the hollow pipe 21 of the light source houses part of the cleaning system 60 of the light source. The cleaning system 60 comprises a pair of magnets 26, 28 arranged on one side and on the other of the light elements. In particular, a first internal magnet 26 is produced in the form of a magnetic bar placed inside the hollow interior of the pipe 21 and being driven along the pipe 21 by a system of pulleys 24, of which a guide cable 25 follows a center axial and longitudinal of the pipe 21. The second magnet 28 is located on an exterior side of the pipe 21 and has an internal wall facing the light source and the first magnet, said internal wall being provided at least partially with a cleaning layer 29 whose shape follows the contour of said light source to clean it during its movement. Preferably, the internal wall of the second magnet also includes a portion 280 without cleaning layer in order to optimize the magnetization force with the internal magnet. Preferably, the pulley system 24 ensuring the movement of the system is driven by one or more motors, and so as to automate the cleaning of an exterior face of the light source 2.

Advantageously, the light source 2 is designed to allow the replacement of a light element and/or the troubleshooting of the cleaning system 60 without compromising the sterility of the culture in progress. To this end, the light source comprises a location column 27 housing said light pipes 21, said location column extending from a bottom of the culture tank C4 and opening out in a sealed manner at the level of a upper closure 11 of the culture tank. As shown to the right of the , the pipe 21 can be extracted from the tank without compromising the tightness and sterility of an internal volume of the culture tank. Seals are therefore provided at the junction of the location column and the closure 11 of the culture tank, and the location columns are provided with closures independent of the closure 11. It is therefore possible to access inside the location tank by removing only the location column closure, and if necessary extract the light pipe and the elements of the cleaning system inside it. In a preferred embodiment, the closure of the culture tank also includes sub-openings allowing the extraction of the second external magnet.

Another objective of the invention is to optimize the photo-bioreactor to allow optimized monitoring and control of a culture of photosynthetic microorganisms.

To this end, the reservoir of the device may include temperature regulation means implemented as a double envelope 3 configured to receive inside a fluid for temperature regulation. This double envelope is present on the vertical walls of the culture tank. As illustrated on the , the temperature regulation means comprise an external heating tank C5 provided with heating and/or cooling means 31 and a fluid inlet 32 and outlet 33 connected to an internal space of the double envelope. In another embodiment, the culture tank integrates an exterior or interior coil as a means of temperature regulation.

The C4 culture tank of the invention is also provided with at least two sampling zones connected by a circuit of conduits 44 to an analysis tank 40 external to said C4 culture tank. The sampling zones can be implemented at the level of the bubble network. The C8 analysis tank includes pH and nutrient sensors (glucose, minerals, vitamins), and a cell concentration measurement device. The cell concentration is calculated in a known manner relative to the optical density of the culture medium, and by means of a turbidimeter. As illustrated on the , the sampling is done using a pump P, and the sampling conduit circuit 44 is configured to return the culture medium taken to the culture tank.

In order to allow in-depth monitoring of growth kinetics in the culture medium, the C4 culture tank integrates inside photoresistors 5 making it possible to measure a light flux in different zones of the culture medium, and reflecting the cellular concentration in said zones. . It is thus possible to obtain a 3D map of the cell concentration in the different zones of the culture tank.

The device of the invention can also be adapted for large culture volumes. The culture tank therefore has a larger volume and the invention proposes to integrate a plurality of light sources 2 inside it in order to illuminate said volume. There schematically illustrates the geometry of such a photo bioreactor seen from the front and the a cross section seen from the top. The light sources 2 are positioned so that their illuminated areas 220 are adjacent and cover the largest volume of culture medium possible. When the illuminated zones do not overlap, so-called dark zones 230 are formed between the illuminated zones 220. The invention proposes to configure the CO ₂ injection bubble network 6 so that the gas outlets 61 are positioned at the level dark zones 230, and the injected gas limits the passage time of microorganisms in the dark zones. According to the illustrated embodiment, the bubble network 6 forms a horizontal grid, and the gas outlets 61 are positioned at the corners of the grid. In this embodiment, the different light sources 2 can be configured with different wavelengths, and so as to allow the cultivation of microorganisms with different needs.

According to one objective of the invention, the photo-bioreactor can be designed as a culture system comprising a plurality of tanks allowing automated or semi-automated culture. Advantageously, the culture system is suitable for the automated cultivation of demanding or sensitive microorganisms, and for any type of culture, such as continuous, batch or fed batch. The invention notably proposes a culture system avoiding sudden changes in culture conditions when compounds are added to the C4 culture tank.

For these purposes, the system of the invention comprises a mixing tank C3 configured to previously prepare the culture medium to be injected into the culture tank C4. The mixing tank comprises in particular mixing means, heating means such as heating mats TC1, TC2, pH adjustment means C10, C11, a temperature sensor T1, and a medium analysis tank C5 culture integrating at least one pH sensor. Advantageously, the control unit makes it possible to activate and control all the means of the mixing tank, and so as to define and control a volume, a concentration, a temperature and pH of the culture medium to be prepared and injected. in the culture tank. The culture in the PBR will therefore not be stressed by the addition of new culture medium, the latter being able to be done at the same concentration, temperature and pH as the medium in the culture tank, or at least at similar conditions.

In particular, the system comprises a water storage tank C1 provided with a current water inlet and an outlet to a sterilization system, for example with UV light, and making it possible to supply sterile water to the mixing tank C3. In addition, the C1 water storage tank allows the evaporation of certain unwanted molecules such as chlorine.

The system also includes pH tanks C10, C11 for storing pH adjustment solutions, the latter being connected to the mixing tank C3 and/or directly to the culture tank C4 for the injection of pH solutions. pH adjustment in the latter. The system also includes a C7 molecule tank for storing nutrients and injecting micronutrients such as carbon molecules, minerals, vitamins and other compounds of interest. The culture system also includes a module or harvest tank C6 connected to an outlet of the culture tank C4, and allowing all or part of the culture medium to be taken.

As illustrated in , liquid transfers between the different tanks is ensured by transfer means comprising at least one pump P, a flow meter D or a solenoid valve EV under the control of the control unit and being assigned to each of the tanks of the system. The device also includes a nutrient storage tank C2 configured to transfer liquid nutrients to a mixing tank C3. In another embodiment, the culture medium is prepared from nutrients in the solid phase, and the transfer means assigned to the nutrient storage tank C2 are of the endless screw metering type, and/or the storage tank storage carried out in the form of a differential gravimetric dispenser.

Whatever the embodiment, the control unit comprises a processor and a program of instructions saved in a memory coupled to said processor, said instructions being executed by the processor to control the operating conditions of said culture system. The system is designed in particular for monitoring and controlling the quantity and speed of transport of liquid or solid between tanks while maintaining variables in certain tanks (temperature, pH, etc.). The control unit is for example a central controller model i3CL12Y/10D14-SEHF or SMT_CD_R20.

The system also includes a user interface allowing the selection of the operating conditions of the system and the monitoring of its operation, said interface being designed to display:

- a set of tanks (literation) as well as the transfer flows (flow rate) between the tanks;

-lighting intensity (in lumen and micromole of photon per s and m2) lighting time, flash;

-a graph of turbidity or cell concentration as a function of time;

-a graph of photoresistance versus time;

-a value of the pH and temperature of the tanks;

-a graph of conductimetry as a function of time;

- a percentage of CO ₂ in the medium in the C4 culture tank and the CO ₂ injection rate;

- a value of various components such as sugar

- a ratio of CO ₂ absorbed in relation to CO ₂ injected.

Likewise, all pH, flow, temperature, light intensity and lighting mode values can be modified in the same operating cycle on this interface.

Advantageously, the system includes different cycles allowing the automation of a culture, including the cycles of starting, washing, rinsing, and starting and stopping a cell culture.

Examples of these cycles are given below in a non-limiting manner:

Cycle 1: Initialization of the functional volumes in relation to the level sensors of the system tanks:

- Initial state: Waiting.

- Button: Volume initialization.

- Filling of C1, C4 (with C8), C2, C3 (with C9) up to the signal from the level sensor CNC1, CNC3, CNC4.

- Recording of the volume of liquid associated with the level/tank sensors.

- END.

Cycle 2: bleach wash (or other sterilizing product)

- Initial state: Waiting

- Button: Sterilization

- Filling of X liters of bleach in the water storage tank C1 to be indicated to the control unit by the operator.

- Filling of mixing tank C3 and from water storage tank C1

- Filling of the nutrient storage tank C2 and from the water mixing tank C3.

- Triggering of a mixing pump of the nutrient storage tank C2.

- Filling of the mixing tank C3 and from the water storage tank C1 + activation of the pump P3 supplying the analysis tank C9 (after a certain liter in the mixing tank C3 defined by the operator) .

- Triggering mixing pump of mixing tank C3

- Sterilization pH pipes (P9-P10) connecting the pH tanks (C9, C10)

- Filling culture tank C4 (+ activation of pump P8 assigned to analysis tank C8 after a certain liter in culture tank C4) from mixing tank C3

- Sterilization pipe connected to the C4 culture tank

-Empty culture tank C4 from harvest tank C6

-P8 pump stop

-Empty mixing tank C3 into culture tank C4 + activation of pump P8

-Drain C4 + pump stop P8

-END

Cycle 3: Rinse

-Initial state: Waiting

-Button: Rinse

-Filling of X L of water to be indicated to the machine by the operator. (pH tank, Molecule)

-Filling C1 up to the level sensor.

-Filling C3 with water and activating brewing pump

-Filling C2 with water from tank C3 and activating brewing pump

-Filling mixing tank C3 from nutrient storage tank C2

-Empty pH tanks C10, C11 in C3 mixing tank and empty the surplus in C4 culture tank for C3 mixing tank

-Filling of culture tank C4 (+ activation of pump P8) from mixing tank C3.

-Empty culture tank C4

-P8 pump stop

-Empty molecule tank in C4 culture tank and empty C4 culture tank

-If there is water left in the tanks, empty into mixing tank C3

-Empty mixing tank C3 into culture tank C4 and Empty culture tank C4 into harvest tank C6

-END

Cycle 4: Start of cell culture

-Initial state: Waiting

-Button: Start

-Filling of the water storage tank C1 with water up to the level sensor CNC1

-Filling of the nutrient storage tank C2 by an operator with a quantity

-Activation of tank C2 mixing pumps

-The operator indicates the desired dilution of the C2 liquid with the C1 water in the C3 mixing tank.

-Mixing (+ mixing pump actuation from a liquid level with the option of activating the UV filter (yes OR no). Visualization of flow rates and possible modification.

-Activation of 2 heating mats TC1, TC2 of the mixing tank C3 up to the set temperature indicated by the operator

-Ignition of light sources 2 in the culture tank C4 at the chosen intensity, display of the intensity measurement given by the photoresistor.

-Filling by the operator of X L of algae in C4 culture tank to indicate to the control unit.

-P8 pump activation

-Filling of culture tank C4 from mixing tank C3 with a chosen flow rate Y to the level sensor CNC4 or chosen volume.

-While filling the culture tank C4 with the medium contained in the mixing tank C3:

-Filling the double jacket of the C4 culture tank and heating the C5 heating tank to the set temperature. Maintaining this function during the process.

-Activation of the arrival of the Co2/air mixture at the C0 ₂ concentration given by the operator. Maintaining this function during the process

-Activation of the pH meter, regulation of the pH (set pH): Two modes to choose from: regulate with PH tank (basic liquid OR Acid indicated by the operator) OR regulation thanks to the arrival of Co2 (the CO2 lowers the pH). Maintaining this function during the process.

-Activation of the turbidimeter/spectrophotometer and conductivity meter + other possible sensor

-Emptying of the C4 culture tank according to 2 modes: Renewal mode of x percent per day with flow rate adjustment OR emptying of X L at a given time interval.

-The middle of the mixing tank C3 will be renewed when the level falls below a threshold chosen by the operator until it reaches its level sensor CNC3 OR the volume chosen by the operator.

-Injection of a molecule from the C7 molecule tank if instructed by the operator.

The system of the invention is therefore very advantageous in that it is designed to facilitate all of the tasks necessary for a user to carry out cell culture, and requires minimal user intervention. On the other hand, the system is designed to have very precise control of cultivation conditions and is therefore very advantageous for experimental cultivation and research on photosynthetic microorganisms. Indeed, the system allows total and precise configuration of the growing conditions, and in particular the lighting mode.

The system of the invention therefore makes it possible to obtain high biomass production yields. Likewise, its great autonomy, its capacity to absorb CO ₂ as well as its high yield of nutrients make it possible to envisage this cultivation system in space colonies. Indeed, the spatial constraints are in line with the capacities that this bioreactor can offer, namely a high surface yield, a capacity to recycle the CO ₂ of the astronauts and their waste (urine, feces, etc.) or even the capacity to be able to cultivate the algae without contamination from the external environment.

We can consider another, more down-to-earth type of use as a growing system that produces food in spaces unsuitable for standard plant growing. It can, for example, be used in undernourished countries as an autonomous installation which will supply the food needs of the sector. Of course, the system can also be connected to a polluting installation and recover the CO ₂ emitted by this installation.

Claims (19)

Photo-bioreactor device (100), said device (100) comprising a culture tank (C4), a light source (2) with LED light-emitting diodes, a power regulation module of said light source (2) and a control unit. control (1), characterized in that:
-the light source (2) is configurable in intensity, and preferably in wavelength by means of said power regulation module controlled by said control unit (1), and
-the regulation module is powered by a direct current and implements analog regulation to control a power supply of the light source (2) varying the light intensity. Device (100) according to claim 1, in which the light source (2) is configurable according to a flash lighting mode, and the device comprises a flash regulation module implementing digital regulation controlled by the control unit ( 1), such as PWM type, to activate and deactivate said light source (2) Device according to one of the preceding claims, in which the light source is configurable in wavelength and variably over an operating cycle, and the device comprises a power regulation module under analog control for each channel supplying one or LEDs from said light source. Device (100) according to one of the preceding claims, in which the light source (2) comprises at least one light sensor in communication with said control unit (1), and the latter implements feedback control of a command power supply of the light source (2) as a function of a luminous flux measured by said light sensor, and in which said culture tank preferably comprises one or more walls coated with a reflective layer arranged to reflect the light from said light source. Device (100) according to one of the preceding claims, in which said light source (2) is integrated inside the culture tank (C4) in the form of a vertical light pipe (21), and the light source (2) comprises a location column (27) extending from a bottom of the culture tank (C4) and opening out in a sealed manner at an upper closure (11) of said culture tank, and in which the light pipe (21) is housed inside said location column (27), and an upper opening of the location column (27) is configured as an independent closable opening, and for retaining the sealing of an internal volume of the culture tank (C4) when it is opened. Device (100) according to one of the preceding claims, comprising a cleaning mechanism (60) of an external wall of the light source (2) in contact with the culture medium, said cleaning mechanism (60) comprising a pair magnets (26,28) arranged on one side and the other of said external wall of the light source (2), and being driven by a system of pulleys (24) to move along the light source (2). Device (100) according to claims 5 and 6, wherein said system of pulleys (24), and an internal magnet (26) of said pair of magnets are arranged inside the hollow interior of the light pipe (21) of the source light, and the second magnet (28) of said pair of magnets comprises a cleaning element (29) in contact with the external wall of the location column (27). Device (100) according to one of the preceding claims, in which the culture tank (C4) comprises one or more additional light sensors (5) configured to measure a luminous flux in different zones of an internal volume of said culture tank. culture (C4) receiving culture medium. Device (100) according to one of the preceding claims, in which the culture tank (C4) is connected to an analysis tank (C8) integrating pH and nutrient sensors, and a cell concentration measuring device , such as a turbidimeter. Device (100) according to one of the preceding claims, in which the control unit (1) comprises a user interface and an application configured to display a set of measurements from the sensors of the device, and making it possible to configure the lighting mode of the light source (2). Device (100) according to one of the preceding claims, comprising a lower gas inlet 40, such as CO _2, said inlet being configured to inject gas towards the top of the culture tank, and preferably the device comprises means of sterilizing air and controlling the air injection flow and its CO ₂ level. Device (100) according to one of the preceding claims, in which the culture tank (C4) integrates a plurality of internal light sources (2) in the form of light pipes (21), each light pipe defining an illuminated zone (220) inside the culture tank, and said device also comprises a gas bubbling network (6) comprising outlets (61) positioned outside the illuminated zones (220) and acting as a means of mixing the culture medium. Automated culture system comprising a photo-bioreactor device comprising a culture tank such as the device (100) according to one of claims 1 to 12, said system also comprising a mixing tank (C3), a storage tank of water (C1), and a nutrient storage tank interconnected by a circuit of pipes, and comprising a control unit comprising a processor and a memory coupled to said processor, and instructions saved in the memory and executed by the processor for control the operating conditions of said culture system, characterized in that :
-the culture tank (C4) has an inlet connected to the mixing tank (C3) for its supply of culture medium, and
- the mixing tank (C3) comprises an inlet connected to the water storage tank (C1), an inlet connected to the nutrient storage tank (C2), mixing means, temperature adjustment means , and means of controlling the pH (C10, C11), and in that
-the system is configured to prepare the culture medium in the mixing tank (C3) at a programmable concentration, temperature and pH by means of said control unit (1), and
-the system comprises transfer means under control of the control unit (1) and being assigned to each of the tanks of the system to activate and control a volume and a flow rate of liquid or solid transferred between said tanks. Culture system according to claim 13, in which the culture tank (C4) is connected to an analysis tank (C8) in communication with the control unit (1) and integrating pH sensors, of at least a nutrient, and a device for measuring cellular concentration, such as a turbidimeter, in which system the control unit (1) includes a program with saved instructions to activate the introduction of the culture medium contained in the tank mixture (3) as a function of the parameters measured in the analysis tank (C8), such as a cell concentration, a pH or a concentration of nutrients. Culture system according to one of claims 13 to 14, in which the culture tank comprises an inlet connected to at least one pH tank (C10) comprising a pH adjustment solution, and a CO ₂ inlet (40 ) connected to a CO ₂ source, and in which the control unit comprises a program comprising saved instructions for regulating the pH in said culture tank (C4) to inject the pH and/or CO ₂ solution into activating transfer means assigned respectively to said CO ₂ source and pH tank. Cultivation system according to one of claims 13 or 14, in which the culture tank (C4) comprises an outlet connected to a harvest tank (C6), and transfer means under control of the control unit (1 ) to transfer a volume of liquid contained in the culture tank (C4) to said harvest tank (C6), and in which the control unit (1) includes a culture program making it possible to define a time, a frequency and a volume of liquid to be extracted from said culture tank (C4) to the harvest tank (C6) and/or a volume of liquid to be injected into said culture tank (C4) from the mixing tank (C3). Cultivation system according to claim 16, in which the transfer means between the tanks are bidirectional and the control unit (1) comprises a rinsing program comprising saved instructions for activating transfer means assigned to the storage tank d water (C1) and inject a liquid into the mixing tank (C3) and rinse all the other tanks of the culture system (C2, C4, C5, C7, C8, C9 C10, C11) from said liquid injected into the mixing tank, by sequentially operating transfer means assigned to each of said tanks of the system in a preconfigured order, and to empty the rinsing liquid injected into the system from the algae harvesting tank. Culture system according to one of claims 13 to 16, said system comprising a user interface making it possible to select a culture program with a culture duration, a volume and a frequency of injection and extraction of volume of culture medium in and from the culture tank and with a controllable flow rate, as well as displaying measurements from a set of temperature, light, pH, cell concentration and nutrient sensors of said culture system. Cultivation system according to one of claims 13 to 17, in which the control unit (1) comprises a communication module, and the system comprises a remote server hosting a database, said database comprising operation of the cultivation system downloadable and executable by the control unit.