ES2387174B1 - CELL CULTURE SYSTEM FOR THE PRODUCTION OF PHOTOSYNTHETIC MICROORGANISMS - Google Patents

Abstract

Cell culture system for the production of photosynthetic microorganisms. # The system constitutes what is a panelar photobioreactor, comprising a plurality of modules or culture chambers (1) arranged in series, thus expanding the volume and also comprising agitation means by microbubbles in each culture chamber (1). It also includes panels of lights (8) insertable / intercalable, as well as temperature control means and ports for the entry of nutrients and crop output, as well as for the measurement and control of the main physical-chemical parameters involved in the growth of the microorganism and therefore in the evolution of the crop.

Description

CELL CULTURE SYSTEM FOR THE PRODUCTION OF PHOTOSYNTHETIC MICROORGANISMS

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OBJECT OF THE INVENTION

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The present invention relates to a cell culture system for the production of photosynthetic microorganisms, constituting what is known as a paneled fluidized bed photobioreactor, based on incorporating a series of modules materialized in culture chambers arranged in series, whose volume is expandable, counting each module or chamber with micro bubble agitation means. The system is part of the field of biotechnology and chemical and bioprocess engineering, and aims to minimize the cultivation area with the consequent saving of necessary land, based on the modularity of the system that makes it possible to serially attach different modules of culture, scaling the volume of culture to the desired volume.

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BACKGROUND OF THE INVENTION Photobioreactors are devices for the cultivation of photosynthetic microorganisms such as microalgae, cyanobacteria or photosynthetic bacteria, in which the growth and multiplication of the

number of cells, favoring the production of biomass and / or

Different metabolites of interest. They consist basically of a

culture vessel exposed to a light source, which is supplied with

nutrients necessary for optimal crop growth and / or production

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of metabolites

So far, multiple designs of

photobioreactors for the cultivation of photoautotrophic organisms, which have

allowed intensive cultivation thereof. Can basically

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distinguish two types of basic systems or designs for the production of

photoautotrophic microorganisms; open systems, in which cultivation

is in contact with the atmosphere, and closed systems, commonly

called photobioreactors, in which the crop has little or no contact

with the atmosphere

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The pnmeros are the simplest from the point of view

Technological and, perhaps for this reason, have traditionally been the most used.

Most of these systems are of the carousel or raceway type, which allow

reach cell densities around lg of cells (dry weight) per liter.

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These systems are made up of shallow channels (water level

15-20cm) in the form of a closed circuit, in which the culture medium is

driven by rotating vanes. Although they have the advantage of bass

operating cost, require large areas of land, reach low

Productivities, have a high consumption of C02, crops suffer with

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Pollution frequency, product recovery from the media

diluted that are reached is expensive, and it is difficult to control variables

   Environmental as temperature.

These disadvantages of open systems have stimulated the development of closed systems or photobioreactors, which have a greater overall performance and a much more exhaustive control of all the parameters involved in the crop, thus saving some of the obstacles that currently curb the development of microalgae cultivation technology in general and its production on an industrial scale at low cost.

Within the closed systems, there are also design variations fundamentally related to the geometry of the space destined to house the crop, and in many cases aimed at improving the use of light by the microorganism. In crops where other factors are not limiting, this availability of light, and its use by the microorganism, determine photosynthetic activity and therefore the speed of growth and productivity of the system. Thus, and although there are modifications of each of the following geometries, three types of designs can be basically distinguished: panelar photobioreactors, bubble column photobioreactors and tubular photobioreactors.

Each of these systems has been described in various scientific documents and subject to several patents.

Thus, in the international patent WO 2004/074423-A2, a reactor for the cultivation of photosynthetic microorganisms is described based on a culture chamber delimited by walls of transparent material, contained in a metal structure in the form of a mesh, and fluidized by air introduced by the bottom. The system also comprises a mixed cooling system by coil and / or water sprinklers, and the arrangement of

the necessary sensors for the measurement and regulation of the main

physical-chemical parameters of the crop.

U.S. Patent 4952511 describes a photobioreactor

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for the cultivation of photosynthetic microorganisms. This photobioreactor

it comprises a tank, at least one light chamber, which extends towards

inside the tank, and at least one high intensity lamp, whose light is

Directs to the light chamber. Each of the light cameras has at least one

transparent wall and a device for essentially distribution

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Uniform lamp light on the transparent wall.

For the industrial development of the cultivation technology of

photoautotrophic microorganisms it is necessary to perform the scaling of

closed photobioreactor systems. This escalation still has limitations

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important, as there are key issues that must still be resolved as the

effective and efficient use of light, the supply of co2 with the

lowest possible losses, or the elimination of oxygen generated during the

photosynthesis, whose accumulation can inhibit metabolism and produce

crop damage.

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For this purpose tubular systems have been tested, both

vertical like horizontal of column of bubbling or panelares. The

more determined attempts regarding the scaling of these systems have been

produced in tubular systems, considered the most suitable for

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Commercial cultivation of large-scale microalgae. However, they continue

appearing some of the fundamental problems mentioned above,

such as the accumulation of dissolved oxygen (product of photosynthesis), the

   C02 depletion, or pH variations, that limit the length of

tubes and consequently the scaling of the system. Therefore the reactors

Tubular cannot be scaled indefinitely, and production plants to

large scale depend partly on multiplying the number of units of

reactors

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In addition to scaling, another of the fundamental problems to the

time to obtain high biomass productivity is related to the

Optimum distribution of light inside the crop. Cells in a

photobioreactors are exposed to high light intensities in the

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near the wall, while in the central areas they can reach

being in darkness due to the effect of self-name. The currents in the

liquid medium move cells through areas with different lighting

there is a fluctuation in the light regime for each cell

individual that passes through the different areas, illuminated or not. In this sense,

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one could speak of three light zones in the reactor: an outer zone, close to

the wall, which is exposed to high intensities of light and can cause

photoinhibition (damage due to excess light); an intermediate zone with

ideal lighting; and an internal area with lack of light and high speed of

breathing.

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DESCRIPTION OF THE INVENTION

The system that is recommended has been designed to solve the

problem described above, first providing a

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modularity of the same that makes it possible to couple different crop modules

teach

   Likewise, the special configuration and geometry of the system, which

from now on it will be described, in the form of vertical panels, to minimize

the cultivation area, with the consequent saving of land.

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More specifically, the system of the invention, constituting a fluidized bed panelar photobioreactor, comprises a plurality of modules in series, scalable, each module being formed by a sealed culture chamber established by a frame delimited by two transparent plates, joined between if by mechanical or hydraulic means, plates and frame of the culture chamber being mounted on a horizontal platform and arranged vertically on a rail system.

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The module or culture chamber, and specifically the framework from which it is constituted, is equipped with different ports, in some cases for nutrient entry, in other cases for crop exit, as well as for gas input and for assembly of different sensors that allow you to track the evolution of the crop, sensors that can be specific to know the pH, dissolved oxygen, CO2, temperature, etc.

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On the other hand, the plates that participate in the culture chamber, can be of variable thickness depending on the passage of light required for the crop, as well as the frame, which will be metallic or plastic, so that the said thickness It can be adjusted by varying the thickness of the plate that is mounted on the frame, or by adding new frames to achieve the desired light path.

   The system includes means that direct light from the outside to the cultivation space, that is to the camera, elements that can be placed

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annexes to each module or cultivation chamber or to be insertable light panels between adjacent culture modules, providing light on both sides, with the particularity that the light panels can have as emission sources, white-light lamps, diodes LED's, or any other source of light usable by the cell.

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The system can be complemented with cooling modules attached to each module or culture chamber, in those cases where the light source raises the temperature above the optimum value for cell growth and / or the production of metabolites of interest.

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These eventual refrigeration modules are constituted by a frame adjacent to the culture module, with which one of its plates shares, with which this shared plate constitutes a large contact surface through which heat transfer is carried out by conduction between the cooling fluid and the culture.

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It should be said that in each case the refrigeration module is connected to a refrigeration unit that maintains the temperature of the refrigerant fluid at the appropriate value for the growth of the microorganism and / or the production of metabolites of interest.

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Another feature presented by the system of the invention is its modular nature and ability to disassemble, to facilitate cleaning and versatility.

   As for the microbubble stirring medium in each culture chamber, it is based on diffusers through which

the gases inside the chamber are injected through the lower part of the chamber, producing an effective agitation of the crop, so that these diffusers will preferably consist of a porous material that will occupy total

or partially the surface of the base of the module or culture chamber, promoting internal agitation by forming microbubbles.

The system can also be complemented with gas humidification means before entering the culture chamber, thereby preventing evaporation.

It has also been provided that optionally, pH control means of the culture medium, connected with the injection media of C02, are included, which allows the pH to be controlled by injection of C02 on demand, depending on the value measured inside the culture .

The culture medium is added to the chamber through an entrance or port provided at the top, connecting with the corresponding feeding tank of the culture medium to the chamber, said feeding tank being able to have an additional lung tank of C02 , which minimizes its consumption.

Ports are also provided in the upper part to add an antifoam substance if necessary (to avoid excessive foaming), these ports being connected to the corresponding sensor to control the formation of foam by opening / closing the respective valve defoamer addition if necessary.

It is also provided that the system may optionally include a gas condenser (air / C02), to maintain the air balance / C02 inside the culture chamber, avoiding evaporation, for which it is connected to the cold unit , thus condensing the evaporated gas during the process.

It is also planned to include a gas sensor (C02 and 0 2 dissolved), which allows monitoring if necessary the amount of gas consumed by the crop.

Finally, say that the modular configuration of the system can follow a certain sequence that will be modified if it does not require cooling means.

The system thus constituted, in addition to serving for the production of photosynthetic microorganisms, can function as a C02 sink, monitoring the rate of fixation of this greenhouse gas through the cultivation of microorganisms.

Likewise, after conditioning currents rich in C02, such as industrial effluents, the system can be used to reduce emissions from C02 generating industries, converting said gas into biomass and forming part of a hypothetical effluent treatment process to adapt the levels of this gas emitted into the atmosphere to those included in the emission legislation.

DESCRIPTION OF THE DRAWINGS

To complement the description that will then be made and in order to help a better understanding of the features of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

Figure 1.- Shows a schematic representation of what can be considered as a possible configuration of one of the modules or culture chambers, in which a culture frame and a frame to house the cooling fluid participate.

Figure 2.- Shows an enlarged and frontal detail of the frame corresponding to the module or culture chamber, where the ports for the inputs, outputs, sensor connections, etc. are shown.

Figure 3.- Shows a schematic representation according to an exploding perspective of the possible installation of one of the modules of the system of the invention.

Figure 4.- Finally, it shows a possible sequence of the modular configuration of the system, in the case of requiring crop cooling.

PREFERRED EMBODIMENT OF THE INVENTION

As you can see in the referred figures, the system of

invention comprises a plurality of modules formed by cameras of

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crop (1), connected in series as shown in Figure 4,

each chamber comprising a frame (2), called a culture frame, at

which are associated with a pair of plates of transparent material (3), as well as a

heat conductive plate (4), so that if required

refrigeration, the culture frame (2) is complemented by a frame (5)

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corresponding to a cooling device, the camera being completed

with external frames (6) to fix the plates (3) to the culture frame (2).

The frame (5) of the cooling device corresponds to the

cooling module (7) represented in figures 3 and 4, in which

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In addition, a panel of lights (8) has been represented.

Figure 3 shows in particular a possible installation of

one of the system modules, where the culture chamber (1) and

specifically the culture frame (2), includes a series of ports (9)

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for different types of sensors, such as pH, dissolved oxygen, of

temperature, level, etc., for monitoring and controlling the evolution of the

cultivation, as well as to attach the necessary means for maintenance

thereof, such as condenser, antifoam addition, etc. In that

same port is established a port (1 O) for C02 input, as well as

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ports (11) for gas inlet, including in correspondence with a

Upper ports (12) for crop output.

   A port (13) is also included in the upper part for

entrance of the culture medium.

Turning to figure 3, the possible installation of one of the

system modules, with the culture chamber (1), with the ports and

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elements referred to above, the light panel (8), the device

cooling (7), associated with a cold equipment (14), also seeing a

tank (15) for feeding the culture medium to the chamber (1), through

from the top of it, while the introduction of co2 is done at

from a supply bottle (16), and is introduced, along with the air, by

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the corresponding ports, with the help of a compressor (17), which includes

a filter (18) and an air humidifier (19), flow valves being provided

(20) and a control team (21).

In that figure 3 we can see the crop outlet (22), which

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logically it will be connected to the ports (12), also seeing the

sampling output (23), and inputs (24). On top

there is a connection (25) for a level sensor, as well as for input of

antifoam (26).

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The modules, as described, can be coupled in

series, scaling the culture volume to the desired volume, always

according to an arrangement of vertical panels that minimize the

cultivation area

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Optimization of light distribution in the corresponding

culture chambers (1), is conditioned to the thickness between the plates (3) of the

module or culture chamber (1), the thickness of these plates being variable from

   so that light passages appropriate to the culture density can be used,

to optimize productivity.

For its part, to optimize the light regime (light and dark cycles), the gases (air / C02) are injected through the lower part of the culture module 5, determining a microbubble stirring medium, so that the frequency of the referred cycles it promotes an increase in productivity, associated in each case with the intensity of light used, this intensity being also adjustable by means of the light panels (8) already referred to above, provided with intensity varying potentiometer,

10 so that the appropriate adjustment of these variables (light-intensity-light-agitation step), associated with cell density, allows the optimization of the light distribution in the system.

You also have to keep in mind that at the top of each

A culture chamber (1) establishes an air chamber that allows the gaseous exchange with the crop, as well as the possibility of removing the dissolved oxygen generated to avoid concentration values that compromise the growth of the microorganism.

Claims (1)

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1a__ Cell culture system for the production of photosynthetic microorganisms, constituting a fluidized bed panelar photobioreactor, characterized in that it comprises a plurality of modules in series, scalable, each module being formed by a sealed culture chamber (1) established by a frame (2) delimited by two transparent plates (3), joined together by mechanical or hydraulic means, with the particularity that plates (3) and frame (2) of the culture chamber (1) are mounted vertically.

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2a. Cell culture system for the production of photosynthetic microorganisms, according to claim 1, characterized in that the frame (2) of the culture chamber (1) comprises ports (9) for different sensors of pH, dissolved oxygen, CO2 and temperature, for monitoring and controlling the evolution of the crop, said culture frame (2) ports (12) for crop output, a port (13) for the entrance of the culture medium, and ports (10 and 11) for the entrance of air and C02 •

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3a__ Cell culture system for the production of photosynthetic microorganisms, according to previous claims, characterized in that the thickness of the frame (2) of the culture chamber (1) is variable, depending on the passage of light required for the culture, that thickness being adjustable based on the variation of the thickness of the plates (3) associated with the frame itself (2).

4a__ Cell culture system for the production of photosynthetic microorganisms, according to claim 1, characterized in that

includes means or panels (8) that direct light from the outside, to

Supply light on both sides.

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5a__ Cell culture system for the production of photosynthetic microorganisms, according to claim 4, characterized in that the light panels (8) include as emission sources acaloric white light lamps, LEDs or any other usable light source.

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6a. Cell culture system for the production of photosynthetic microorganisms, according to claims 1 and 2, characterized in that optionally refrigeration devices (7) attached to each culture chamber (1) are included, for temperature cooling in case of elevation of this by the light source, above the optimum value for cell growth and / or the production of metabolites of interest, said cooling device being associated with a cold producing equipment (14).

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7a__ Cell culture system for the production of photosynthetic microorganisms, according to claim 6, characterized in that the cooling devices (7) are constituted from a frame (5) adjacent to the frame around the culture chamber (1), sharing a of the plates (3) of this one.

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   8a. Cell culture system for the production of photosynthetic microorganisms, according to claims 1 and 2, characterized in that the entry of gases through the ports (1 O and 11) is carried out by diffusers through which microbubbles are produced and the corresponding effective agitation of the crop, with the particularity that

such diffusers are preferably constituted by a porous material that totally or partially occupies the surface of the base of the culture chamber. ga__ Cell culture system for the production of photosynthetic microorganisms, according to claims 1 and 2, characterized in that it optionally includes a gas humidifier element (19), arranged prior to the corresponding entrances to the culture chamber (1). 1oa.-Cell culture system for the production of photosynthetic microorganisms, according to claims 1 and 2, characterized in that it optionally includes a pH control medium of the culture medium connected to the C02 injection system, allowing the pH to be controlled by injection of C02 on demand, depending on the value measured inside the crop. 11a__ Cell culture system for the production of photosynthetic microorganisms, according to claims 1 and 2, characterized in that the culture entrance to the culture chamber (1) is carried out through an upper port (13) of the corresponding culture frame (2) ), from a feed tank (15), capable of being complemented with an additional co2 tank to minimize its consumption. 12a.-Cell culture system for the production of photosynthetic microorganisms, according to claims 1 and 2, characterized in that a gas supply cylinder is included (16).
13a__ Cell culture system for the production of

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Photosynthetic microorganisms, according to claims 1 and 2, characterized in that optionally foam control means are included through the corresponding port provided in the upper part of the culture frame (2), being complemented by means of injection of an antifoam substance if necessary to Avoid foaming.

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14a. Cell culture system for the production of photosynthetic microorganisms, according to claims 1, 2 and 6, characterized in that optionally a gas condenser is included to maintain their balance inside, that gas condenser being connected to the unit of cold (14) associated with the cooling device (7), for the condensation of the evaporated gas during the process.

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15a. Cell culture system for the production of photosynthetic microorganisms, according to previous claims, characterized in that a control equipment (21) is included for the correct operation of the different equipment and components of the system.

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