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 invention

The present invention relates to the field of photo-bioreactors for the cultivation of photosynthetic microorganisms such as microalgae, and automated cultivation methods. 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.

Technological background

There are many types of PBR photobioreactors for microalgae cultivation today. Most of these devices are designed for laboratory use, and do not allow high-yield biomass production or precise control of lighting and culture conditions. In general, a photobioreactor has at least one open or closed tank to contain the culture medium and a light source to irradiate said tank. Access to light is one of the most limiting factors in crop yields and different photobioreactor models have been proposed to optimize the tank surface area and illuminated volume ratio. On the other hand, powering the lighting also represents one of the most significant costs of operating a PBR. It is therefore desirable to have a tank and a lighting configuration that can illuminate the culture medium as well 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, US patent application 2010/0190227 discloses a photo-bioreactor integrating a light source inside the tank, in particular in the form of a molded plastic LED insert. The photo-bioreactor is designed in several modules, each module comprising a tank integrating an LED insert in the form of a vertical pipe, said insert being positioned on one lateral side of said module, offset from the central axis of the tank, and such that the opposite side of said module integrates an upper opening for connecting a second module to said opening. This document proposes to increase the culture capacity of the photo-bioreactor by vertically stacking several modules communicating with each other via their upper openings, so as to alternate the orientations of the LED inserts at each level to have a helical geometry for positioning said LEDs through the column. This system is advantageous in that it makes it possible to integrate a light source inside the tank and to 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 goal is to provide a lighting system that allows for perfect control of the lighting mode.

Another objective of the invention is to propose a photo-bioreactor suitable for any type of culture (mixotrophy, heterotrophy, batch, continuous or semi-continuous) and allowing the culture conditions to be precisely configured.

Another objective of the invention is to provide 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 light-emitting diodes (LED), a power regulation module for 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 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 that can be activated and controlled precisely to operate according to a desired lighting mode, as well as to vary its light intensity. In particular, the analog regulation of the light intensity makes it possible to ensure true continuity of the lighting when it must be active, while varying its intensity. It will therefore be possible to reliably study the effect of the 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 that 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 a digital regulation controlled by the control unit, such as of the PWM type, to activate and deactivate said light source at high intensity and speed. This lighting mode is very advantageous in that it allows energy savings to be made, 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 supplying 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 a feedback control of a power supply control of the light source as a function of 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 pipe is housed inside said location column, and an upper opening of the location column is configured as an independent closable opening, and making it possible to maintain the sealing of an internal volume of the culture tank 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 external 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 in the hollow interior of the light source pipe, and the second magnet of said pair of magnets comprises a cleaning element in contact with the external 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 luminous 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 _CO2 , 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 flow rate and its CO2 level;

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

The invention also relates to an automated culture system comprising a photo-bioreactor device comprising a culture tank, a mixing tank, a water storage tank, and a nutrient storage tank connected together by a pipe circuit, 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 concentration, temperature and pH programmable 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 system configuration allows the culture tank to be fed with a culture medium with 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.

Similarly, this configuration allows the control unit to be programmed with automated culture programs comprising saved instructions for maintaining or modifying 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 device for measuring cell concentration, such as a turbidimeter. Thus, the control unit comprises a program with saved instructions for activating 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 nutrient concentration.

Preferably, the culture tank also comprises an inlet connected to at least one pH tank comprising a pH adjustment solution, and a _CO2 inlet connected to a _CO2 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 solution and/or _CO2 by activating transfer means assigned respectively to said _CO2 source and pH tank. The pH regulation mode can be selected by the user.

In one embodiment of the system, the culture tank comprises an outlet connected to a harvest tank, and transfer means under the control of the control unit for transferring a volume of liquid contained in the culture tank to said harvest tank, and in which the control unit comprises a culture program making it possible to define a time, a frequency and a volume of liquid to be extracted from said culture tank to the harvest tank and/or a volume of liquid to be injected into 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. For this purpose, the transfer means between the tanks are bidirectional and the control unit comprises a rinsing program comprising saved instructions for activating transfer means assigned to the water storage tank and injecting a liquid into the mixing tank and rinsing a set of tanks of the culture system from said liquid injected into the mixing tank, by sequentially actuating transfer means assigned to each of said tanks of the system in a preconfigured order, and for emptying the liquid injected 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 sterilization of the system. Preferably, the control unit comprises a dedicated sterilization cycle, in which a passage time of the sterilizing liquid in 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.

In addition, the system comprises a user interface for selecting a culture program with a culture duration, a volume and a frequency of injection and extraction of volume of culture medium into and from the culture tank, as well as displaying the measurements of 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 comprises a communication module, and the system comprises 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 attached 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 present invention aims 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 that the photo-bioreactor is 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. illustrates a culture system integrating a photo-bioreactor 100 according to the invention, also called device 100 for the culture of photosynthetic microorganisms and comprising a culture tank C4 having a vertical column shape. The tank C4 defines an internal volume for the culture of said microorganisms and its shape is not limited and can have a circular or polygonal section, such as square.

The 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 photobioreactor will thus make it possible to study the effect of the lighting mode precisely and to control it in order to obtain the best biomass yields or production of a molecule of interest, or to optimize energy consumption. 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. Similarly, the 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 a continuous type analog regulation ( ). This type of regulation ensures a luminous flux that does not vary its voltage in frequency, and is therefore truly continuous. This is particularly important with the use of LEDs, the latter being traditionally controlled in power by a binary type PWM digital modulation with frequency, and which results in the hashing of the signal. That is to say, with PWM regulation the light signal is discontinuous, and formed by light flashes not visible to the human eye. Microalgae are however capable of harvesting light in the order of picoseconds, and are therefore sensitive to these light flashes invisible to the human eye.

In order for the micro algae to be able to access continuous light of constant intensity, the invention proposes to supply the light source with a direct current ( ), and controlled by the control unit according to an 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 an analog regulation, making it possible to maintain a continuous light signal. The flash lighting mode is then activated preferably by means of a preferably dedicated flash regulation module and by a generic digital regulation of the PWM type. For example, the analog regulation of the power can be implemented by means of the RCD-24-1.20 driver, or by means of a Mosfet transistor such as the IRLZ34NPBF accompanied by one or more resistors. This latter 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 a check of the power supplied to said light source. Whatever the embodiment, the control of the light intensity is done by analog regulation and the control of the flash mode by digital piloting

Preferably, the device of the invention comprises a light intensity feedback function for correcting the light flux supply in real time. In particular, the light source integrates a light sensor configured to transmit to the control unit the light intensity detected under operating conditions, and so that the control unit modifies a power command of the regulation module so 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 supply power depending on the ambient temperature. An increase in temperature thus results in a reduction in the quantity of light flux provided by an LED. The colors from amber to red called "AlGalnP" provided by LEDs made of aluminum gallium indium phosphide are the most sensitive to this reduction in light flux, and the colors ranging from blue to green and white (based on "InGaN") are the least sensitive. Therefore, feedback control of light flux input is very advantageous for crops programmed with wavelengths sensitive to this phenomenon, or with programmed wavelength variations.

In a preferred embodiment, the lighting source is configurable in wavelength by means of multichannel LEDs, such as RGB LEDs allowing a wavelength to be adjusted according to the wave power 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 custom emission spectrum, in particular with a specific frequency and duty cycle. A flash regulation module and a power supply 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 variant embodiment not illustrated, a single flash regulation module is implemented placed upstream of the power regulation modules, thus making it possible to limit the number of total components. This latter embodiment is suitable when the same flash signal is implemented for all the 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 back toward the culture medium. Preferably, this reflective layer is present over the entire vertical internal wall of the tank, or at least over a portion and so as to leave one or more windows for viewing 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 a central and longitudinal axis 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 light elements 22 such as light-emitting diodes LED 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 a 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 side of the light elements. In particular, a first internal magnet 26 is produced in the form of a magnetic bar arranged in the hollow interior of the pipe 21 and being driven along the pipe 21 by a system of pulleys 24, a guide cable 25 of which follows an axial and longitudinal center of the pipe 21. The second magnet 28 is located on an outer side of the pipe 21 and comprises 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 matches the contour of said light source to clean it during its movement. Preferably, the inner wall of the second magnet also comprises a portion 280 without a 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 outer 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 current culture. For this purpose, 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 in a sealed manner at an upper closure 11 of the culture tank. As illustrated on the right of the , the pipe 21 can be extracted from the tank without compromising the sealing 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 the interior of the location tank by removing only the closure of the location column, 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 comprises 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.

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

The culture tank C4 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 culture tank C4. The sampling zones can be implemented at the level of the bubble network. The analysis tank C8 comprises pH and nutrient sensors (glucose, minerals, vitamins), and a device for measuring the cell concentration. 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 in the , the sampling is done using a pump P, and the sampling conduit circuit 44 is configured to return the collected culture medium to the culture tank.

In order to allow in-depth monitoring of growth kinetics in the culture medium, the C4 culture tank incorporates photoresistors 5 inside it to measure a light flux in different areas of the culture medium, and reflecting the cell concentration in said areas. It is thus possible to obtain a 3D map of the cell concentration in the different areas 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. schematically illustrates the geometry of such a photobioreactor seen from the front and the a cross-section seen from above. The light sources 2 are positioned so that their illuminated areas 220 are adjacent and cover the largest possible volume of culture medium. When the illuminated areas do not overlap, so-called dark areas 230 are formed between the illuminated areas 220. The invention proposes to configure the CO ₂ injection bubble network 6 so that the gas outlets 61 are positioned at the dark areas 230, and the injected gas limits the passage time of the microorganisms in the dark areas. 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 an 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 culture of demanding or sensitive microorganisms, and for any type of culture, such as continuous, batch or fed batch. The invention proposes in particular a culture system avoiding sudden changes in culture conditions when adding compounds to the culture tank C4.

For these purposes, the system of the invention comprises a mixing tank C3 configured to pre-prepare the culture medium to be injected into the culture tank C4. The mixing tank comprises in particular stirring means, heating means such as heating mats TC1, TC2, pH adjustment means C10, C11, a temperature sensor T1, and a culture medium analysis tank C5 incorporating at least one pH sensor. Advantageously, the control unit makes it possible to actuate and control all of 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 into the culture tank. The culture in the PBR will therefore not be stressed by the supply 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 under similar conditions.

In particular, the system comprises a water storage tank C1 provided with a running water inlet and an outlet to a sterilization system, for example UV light, and allowing a supply of sterile water to the mixing tank C3. In addition, the water storage tank C1 allows the evaporation of certain undesirable 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 injecting pH adjustment solutions into the latter. The system also includes a molecule tank C7 for storing nutrients and injecting micronutrients such as carbon molecules, minerals, vitamins and other compounds of interest. The culture system also includes a harvest module or tank C6 connected to an outlet of the culture tank C4, and allowing all or part of the culture medium to be collected.

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

Regardless of 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 the tanks while maintaining the 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 (liters) as well as the transfer flows (flow rate) between the tanks;

- lighting intensity (in lumens and micromoles of photons 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 _CO2 in the medium in the C4 culture tank and the _CO2 injection rate;

- a value of various components such as sugar

- a ratio of _CO2 absorbed compared to _CO2 injected.

Likewise, all pH, flow rate, 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 start, wash, rinse, and start and stop cycles of a cell culture.

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

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

- Initial state: Pending.

- 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: Pending

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

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

- 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 volume in the mixing tank C3 defined by the operator).

- Triggering of the mixing pump for mixing tank C3

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

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

- Sterilization of the pipe connected to the C4 culture tank

- Emptying culture tank C4 from harvest tank C6

-Pump stop P8

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

- Emptying C4 + stopping pump P8

-END

Cycle 3: Rinse

-Initial state: Pending

-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.

-C3 water filling and activation of the mixing pump

- Filling C2 with water from tank C3 and activation of the mixing pump

-Filling mixing tank C3 from nutrient storage tank C2

- Emptying pH tanks C10, C11 into mixing tank C3 and emptying the surplus into culture tank C4 for mixing tank C3

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

-Emptying culture tank C4

-Pump stop P8

- Emptying molecule tank into C4 culture tank and emptying C4 culture tank

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

- Emptying mixing tank C3 into culture tank C4 and emptying culture tank C4 into harvest tank C6

-END

Cycle 4: Start-up of cell culture

-Initial state: Pending

-Button: Start

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

-Filling of the C2 nutrient storage tank by an operator with a quantity X of liquid to be indicated to the machine.

-Activation of the C2 tank mixing pumps

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

-Mixing (+ actuation of the mixing pump from a liquid level X indicated on the controller) in the mixing tank C3 until filling (CNC3 level sensor OR volume given by the operator) according to the desired dilution with the UV filter activation option (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

- Switching on the light sources 2 in the culture tank C4 at the chosen intensity, displaying the intensity measurement given by the photoresistor.

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

-Activation of pump P8

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

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

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

-Activation of the arrival of the CO2/air mixture at the _CO2 concentration given by the operator. Maintain this function during the process

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

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

- 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 tankC3 will be renewed when the level falls below a threshold chosen by the operator until it reaches its CNC3 level sensor 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 the tasks necessary for a user to carry out a cell culture, and requires minimal user intervention. On the other hand, the system is designed to have very precise control of the culture conditions and is therefore very advantageous for experimental culture and research on photosynthetic microorganisms. Indeed, the system allows total and precise parameterization of the culture conditions, and in particular of the lighting mode.

The system of the invention therefore allows high biomass production yields to be obtained. Similarly, its great autonomy, its capacity to absorb _CO2 as well as its high nutrient yield 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 _CO2 of astronauts and their waste (urine, feces, etc.) or the capacity to cultivate algae without contamination of the external environment.

We can consider another type of more down-to-earth use as a growing system producing food in spaces that are not very suitable for standard plant growing. It can be used, for example, in countries with undernutrition as a stand-alone facility that will supply the food needs of the sector. Of course, the system can also be connected to a polluting facility and recover the _CO2 emitted by this facility.

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 for said light source (2) and a control unit (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 an 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 a digital regulation controlled by the control unit (1), such as of the 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 more LEDs of 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 a feedback control of a power supply control 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, wherein 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 in a sealed manner at an upper closure (11) of said culture tank, and wherein 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 making it possible to maintain 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) for an external wall of the light source (2) in contact with the culture medium, said cleaning mechanism (60) comprising a pair of 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 pulley system (24), and an internal magnet (26) of said pair of magnets are arranged in the hollow interior of the light pipe (21) of the light source, 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 light flux in different zones of an internal volume of said culture tank (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 device for measuring cell concentration, 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 for sterilizing air and controlling the air injection flow rate 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 water storage tank (C1), and a nutrient storage tank connected together by a pipe circuit, 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 (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 pH control means (C10, C11), and in that
-the system is configured to prepare the culture medium in the mixing tank (C3) at a concentration, temperature and pH programmable by means of said control unit (1), and
-the system comprises transfer means under the 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. A culture system according to claim 13, wherein the culture tank (C4) is connected to an analysis tank (C8) in communication with the control unit (1) and integrating pH sensors, at least one nutrient, and a device for measuring cell concentration, such as a turbidimeter, in which system the control unit (1) comprises a program with saved instructions for activating the introduction of the culture medium contained in the mixing tank (3) according to the parameters measured in the analysis tank (C8), such as a cell concentration, a pH or a nutrient concentration. Culture system according to one of claims 13 to 14, wherein the culture tank comprises an inlet connected to at least one pH tank (C10) comprising a pH adjustment solution, and a _CO2 inlet (40) connected to a _CO2 source, and wherein the control unit comprises a program comprising saved instructions for regulating the pH in said culture tank (C4) for injecting pH solution and/or _CO2 by activating transfer means assigned respectively to said _CO2 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 the control of the control unit (1) for transferring a volume of liquid contained in the culture tank (C4) to said harvest tank (C6), and in which the control unit (1) comprises 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). A culture system according to claim 16, wherein the transfer means between the tanks are bidirectional and the control unit (1) comprises a rinsing program comprising stored instructions for activating transfer means assigned to the water storage tank (C1) and injecting liquid into the mixing tank (C3) and rinsing all other tanks of the culture system (C2, C4, C5, C7, C8, C9 C10, C11) from said liquid injected into the mixing tank, by sequentially activating transfer means assigned to each of said tanks of the system in a preconfigured order, and for emptying 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 allowing 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 the measurements of 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 cultivation system operating programs downloadable and executable by the control unit.