CA2393188A1 - Photobioreactor - Google Patents
Photobioreactor Download PDFInfo
- Publication number
- CA2393188A1 CA2393188A1 CA 2393188 CA2393188A CA2393188A1 CA 2393188 A1 CA2393188 A1 CA 2393188A1 CA 2393188 CA2393188 CA 2393188 CA 2393188 A CA2393188 A CA 2393188A CA 2393188 A1 CA2393188 A1 CA 2393188A1
- Authority
- CA
- Canada
- Prior art keywords
- photobioreactor
- liquid
- culture medium
- light
- ions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
- C12M21/00—Bioreactors or fermenters specially adapted for specific uses
- C12M21/02—Photobioreactors
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
- C12M31/00—Means for providing, directing, scattering or concentrating light
- C12M31/10—Means for providing, directing, scattering or concentrating light by light emitting elements located inside the reactor, e.g. LED or OLED
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Organic Chemistry (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Biotechnology (AREA)
- Genetics & Genomics (AREA)
- Biomedical Technology (AREA)
- Biochemistry (AREA)
- General Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Sustainable Development (AREA)
- Microbiology (AREA)
- Molecular Biology (AREA)
- Apparatus Associated With Microorganisms And Enzymes (AREA)
Abstract
A photobioreactor is disclosed for cultivating a photosynthetic organism. This photobioreactory rovides innovative features that allow an easy cleaning of the light source. The photobioreactor has a container for containing a liquid culture medium for cultivating photosynthetic organisms, light-emitting tubes mounted within the container. The photobioreactor also has cleaning devices mounted within the container for cleaning the outer surface of the light-emitting tubes arid actuators for actuating the cleaning devices.
Description
PHOTOBI~REAC"fOR
FIELD OF~THE INVENTION
The present invention relates generally to the field of photobivreactors. More particularly, it concerns a photQbioreactor, a culture unit and a process for cultivating photosynthetic organisms, such as microalgae.
1 o BACKG~R~DUND QF°t'HE INVENTION
The algae biamass artificially pn3duced is usually dried and used as a nutraceutical food for humans. Derived fine biochemical products can be extracted from algae, for instance, cosmetic pigrrrents, fatty acids, antioxidants, proteins with prophylactic action, growth factors, antibiotics, vitamins arnd polysaccharides. The algic biomass can also be useful, in a low dose, to replace or decrease the level of antibiotic in animal food or be useful as a source of proteins. Furthermore, the algic biomass provided in a wet-form, as opposed to a dried form, can tre fem~rented or liquefied by thermal processes to produce fuel. The algae biomass which may have commercial 2 o interests are: Spirulina maximum, Spirulina platensis, Dunaliella saline, Bofrycoccus braunii, Chlorella vulgaris, Chlorella pyrenoidosa, Serenastrum capricvmutum, Scenedesmus auadricauda, Arrabaenopsis, Aulosira, Cylindraspermum, and Tolypothrix.
2 s Various approaches of algae production are known in the art. A first generation of photobioreactors is based an the use of shallow lagoons ag~ated v~iith one or several paddle wheels. The phDtvbioreactars of this first generation have the disadvantage of offering poor productivityto the seasornal any! daily climatic variativrts and are thus to be confined to tropical and subtropical areas. They also have the disadvantage of 3 o being prone to contamination.
Other approaches of algae prorduction have emerged over the past years. An example, is the use of closed cultivating systems which have gained popularity because they overcame the majority of the limitations allotted to the conventional shallow lagoons. The most popular closed cultivating systems are the tubular photobioreactors whose configuration allows to reach high production rates due to s the optimization of their light path, their temperature control and their culture mixture.
This second generation of photobioreactors allows for an automated control and a more effective absorption of C02 used as a source of carbon. It also allows the pH
of the culture medium to be lowered. Examples of tubular photobioreactors are shown in US patents nos. 5,137,828; 5,242,827 and 6,174,720.
The photobioreactors of the first and second generations were constructed to principally receive the sun's daylight. Their productivity is indeed limited to the intensity of the sun, which intensity depends on the photoperiod, the season, the localization and the diurnal cycle. It is possible to provide an artificial light to is compensate for the periods of low intensity. However, in such a case, the energy losses are numerous. The fact that these types of photobioreactors are being laid out outside, even under a greenhouse, also limits their use in more moderate climatic areas.
2 o The use of artificial light as an energy source for the growth of microalgae was the subject of several studies and gave birth to the third generation of photobioreactors.
Photobioreactors of various shapes and employing various systems of artificial lighting are known in the art. Examples of these photobioreactors are given in US
patents nos. 5,104,803; 5,169,051 and 5,614,378. Because their scaling was too 2 s expensive, the photobioreactors of the third generation rarely exceeded the stage of prototype. Furthermore, a major drawback with these photobioreactors, is that they become dirty or contaminated unless special precautions are taken. Indeed, adhesions of microalgae occur in a natural manner, particularly on the walls where light is emitted. The extent of this phenomenon is a function of the cultured algae 3 o species, as well as the constituent material of the light-emitting devices and the culturing conditions. This effect of adhesion of microalgae leads to a reduction in the volume of culture exposed to the light. It also increases the risks of contamination as a result of the development of b~a~cteria andlor protozoa, which develop in the absence of light.
On an other hand, it is now of general knowledge that the main gas causing the s greenhouse effect arrd the reh~eatirng of th-e planet is the carbon dioxide (C02). This gas comes from various sources. COz of anthropic origin is emitted by breathing, fossil combustion vf-fuel and by certain chemical praoesses. It is also shown that the inorganic carbon provided in the form of gaseous COz or of bicarb~anate can be useful as the only source of curb nwfor-thE growth of the microalgae. The gaseous t o COZ is generally directly injected into the culture medium at oon~ntrations reaching 15 %, the balance cvr<sisting of air. Though mare expensive, the bicarbonate, generally provided iwthe form of sodium bicarbonate, is arrothEr source of inorganic carbon assimilable. by the microalgae.
i 15 Several drawbacks were identified concerning the coupling of techniques involving the sequestration by the micnralgae of COZ of anthropic origin. The most important drawbacks are the dependence on the light intensity of the sun, the external temperature, the large surfaces occupied by basins of low yield culture and the C02 absorption towers.
Although many phvtobioreactors have been proposed in the prier art, there is still a need for an improved photobio~actor using artifrcial light as the energy source for photosynthesis. indeed, there is a need for a photobioreactar designed so as to reduce or eliminate the problem described above concerning the accumulation of 2 s microalgae on the light-emitting source. The re is also a need for a photobioreactor that can easily be coupled with techniques involving the recycling of C02 of anthropic origin:
SUMMARY OF~THE INVENTION
An object of the present invention is to provide a photobioreactar that satisfies at least one of the above-mEntion~ed needs.
FIELD OF~THE INVENTION
The present invention relates generally to the field of photobivreactors. More particularly, it concerns a photQbioreactor, a culture unit and a process for cultivating photosynthetic organisms, such as microalgae.
1 o BACKG~R~DUND QF°t'HE INVENTION
The algae biamass artificially pn3duced is usually dried and used as a nutraceutical food for humans. Derived fine biochemical products can be extracted from algae, for instance, cosmetic pigrrrents, fatty acids, antioxidants, proteins with prophylactic action, growth factors, antibiotics, vitamins arnd polysaccharides. The algic biomass can also be useful, in a low dose, to replace or decrease the level of antibiotic in animal food or be useful as a source of proteins. Furthermore, the algic biomass provided in a wet-form, as opposed to a dried form, can tre fem~rented or liquefied by thermal processes to produce fuel. The algae biomass which may have commercial 2 o interests are: Spirulina maximum, Spirulina platensis, Dunaliella saline, Bofrycoccus braunii, Chlorella vulgaris, Chlorella pyrenoidosa, Serenastrum capricvmutum, Scenedesmus auadricauda, Arrabaenopsis, Aulosira, Cylindraspermum, and Tolypothrix.
2 s Various approaches of algae production are known in the art. A first generation of photobioreactors is based an the use of shallow lagoons ag~ated v~iith one or several paddle wheels. The phDtvbioreactars of this first generation have the disadvantage of offering poor productivityto the seasornal any! daily climatic variativrts and are thus to be confined to tropical and subtropical areas. They also have the disadvantage of 3 o being prone to contamination.
Other approaches of algae prorduction have emerged over the past years. An example, is the use of closed cultivating systems which have gained popularity because they overcame the majority of the limitations allotted to the conventional shallow lagoons. The most popular closed cultivating systems are the tubular photobioreactors whose configuration allows to reach high production rates due to s the optimization of their light path, their temperature control and their culture mixture.
This second generation of photobioreactors allows for an automated control and a more effective absorption of C02 used as a source of carbon. It also allows the pH
of the culture medium to be lowered. Examples of tubular photobioreactors are shown in US patents nos. 5,137,828; 5,242,827 and 6,174,720.
The photobioreactors of the first and second generations were constructed to principally receive the sun's daylight. Their productivity is indeed limited to the intensity of the sun, which intensity depends on the photoperiod, the season, the localization and the diurnal cycle. It is possible to provide an artificial light to is compensate for the periods of low intensity. However, in such a case, the energy losses are numerous. The fact that these types of photobioreactors are being laid out outside, even under a greenhouse, also limits their use in more moderate climatic areas.
2 o The use of artificial light as an energy source for the growth of microalgae was the subject of several studies and gave birth to the third generation of photobioreactors.
Photobioreactors of various shapes and employing various systems of artificial lighting are known in the art. Examples of these photobioreactors are given in US
patents nos. 5,104,803; 5,169,051 and 5,614,378. Because their scaling was too 2 s expensive, the photobioreactors of the third generation rarely exceeded the stage of prototype. Furthermore, a major drawback with these photobioreactors, is that they become dirty or contaminated unless special precautions are taken. Indeed, adhesions of microalgae occur in a natural manner, particularly on the walls where light is emitted. The extent of this phenomenon is a function of the cultured algae 3 o species, as well as the constituent material of the light-emitting devices and the culturing conditions. This effect of adhesion of microalgae leads to a reduction in the volume of culture exposed to the light. It also increases the risks of contamination as a result of the development of b~a~cteria andlor protozoa, which develop in the absence of light.
On an other hand, it is now of general knowledge that the main gas causing the s greenhouse effect arrd the reh~eatirng of th-e planet is the carbon dioxide (C02). This gas comes from various sources. COz of anthropic origin is emitted by breathing, fossil combustion vf-fuel and by certain chemical praoesses. It is also shown that the inorganic carbon provided in the form of gaseous COz or of bicarb~anate can be useful as the only source of curb nwfor-thE growth of the microalgae. The gaseous t o COZ is generally directly injected into the culture medium at oon~ntrations reaching 15 %, the balance cvr<sisting of air. Though mare expensive, the bicarbonate, generally provided iwthe form of sodium bicarbonate, is arrothEr source of inorganic carbon assimilable. by the microalgae.
i 15 Several drawbacks were identified concerning the coupling of techniques involving the sequestration by the micnralgae of COZ of anthropic origin. The most important drawbacks are the dependence on the light intensity of the sun, the external temperature, the large surfaces occupied by basins of low yield culture and the C02 absorption towers.
Although many phvtobioreactors have been proposed in the prier art, there is still a need for an improved photobio~actor using artifrcial light as the energy source for photosynthesis. indeed, there is a need for a photobioreactar designed so as to reduce or eliminate the problem described above concerning the accumulation of 2 s microalgae on the light-emitting source. The re is also a need for a photobioreactor that can easily be coupled with techniques involving the recycling of C02 of anthropic origin:
SUMMARY OF~THE INVENTION
An object of the present invention is to provide a photobioreactar that satisfies at least one of the above-mEntion~ed needs.
According to the present invention that object is achieved with a photabioreactor comprising a container far containing a liquid culture medium for cultivating photosynthetic organisms, and a plurality of parallel light-emitting tubes mounted s within the container-and extending in a first direction, each light-emitting tube having an outer surface. The photobioreactor~furthe~r comprises cleaning means mounted within the cantairrer-far cleatring the outer-surface of the light-emitting tubes, and actuating means foractuating the cleaning means.
t o Thanks to the cleaningmeans provided within the container and the actuating means for actuating the same, it is possible withwthe present invention to easily get rid of the cultivated organisms which mray block the light source by adhering to the same.
Also, the simplicity of its concept rrrakes it a very attractive and easy tool to be used for growing a desired organism at a substantially low cost.
is According to another aspect of the invention, there is provided a culture unit for cultivating photosynthetic organisms, cam~prising a photobioreactor for cultivating a photosynthetic organism in a liquid culture medium and a bioreactorfor producing bicarbonate ions and hydrogen ions from a C02-containing gas, the bioreactor 2 o comprising:
- a reaction chamber containing immobilized carbonic anhydrase or analog thev~of caprable of catalyzing the hydration of dissolved CO2 into the bicarbonates ions and hydrogen ions, - a liquid inlet in fluid communication with the reaction chamber, for 2 s receiving a liquid, - . a gas inlet in fluid communication with the reaction chamber, for receiving a C02 -containing gas; and - a liquid outlet in fluid communication with the reaction chamber, for dispensing a liquid solution containing the bicarbonates ions and 3 o hydrogen ions.
The culture unit furtherwcomprises meanswfor~transferring the solution of bicarbonates ions and hydn~gen ions dispensed from~the liquid outlet to the photobioreactor.
As can be appreciated, orre advantage of a culture unit as defined above is that it allows the use, at low cost, ofi bicarbonate ions as the source of carbon necessary for the growth of the organisms. Also, thanks to the use of a COZ-containing gas in s the bioreactor, the unit has the advantage of reducing C02 contained in the air.
Consequently, it also helps reducing the greenhouse effect mentioned above.
The invention also proposes a pracess-for-prvducirng photosynthetic organisms, the process comprising the steps of:
1 o a) cultivating a photosynthetic organism in a photobioreactor as defined above, and thereby obtaining a liquid culture medium containing photosynthetic organisms;
b) removing from~the phvtobioreactor-a portion of the liquid culture medium;
and I~
is c) separating the liquid culture medium of step b) into a solid phase containing the photosynthetic organisms acrd a liquid phase.
BI~IEF~DE5C~fPTI~iN OF'-THE~DRAWINGS
These and other objects and advantages of~the invention will bECame apparent upon reading the detailed description and upon referring to the drawings in which Figure 1 is a perspective view of a photobioreactor according to a first preferred embodiment of the invenfiion, with one side wall removed to better see the inside of 2 s the photobiareactor.
Figure 2 is a perspective view of a photobioreactar~according to a second preferred embodiment of the invention.
Figure 3 is a top view of thwphotobiorea~ctar of figure 2.
Figure 4 is a cross-sectional side view taken along the line A-A of figure 3.
Figure 5 is an enlarged view of section B of figure 4.
Figure 6 is an exploded view of~thE support frame of the photobian=actor of figure s Figure 7 is a schematic flow chart of a first preferred variant of the process for producing photosynthetic organisms according to the present invention; and Figure 8 is a schematic flow chart of a second prefemad variant of the process for producing photosynthEtic organisms accordirng to the present invention.
~. o DESC~(PTI~(3N ~~PREFERRED EIffiBQDIIVIENTS
As shown in the drawings and in accordance with a first aspect of the invention, a is photobioreactor for cultivating photosynthetic organisms is proposed. The photobioreactor of the invention is suitable for the culture of any kind of photosynthetic organism, such as plant cells and unicellular or multicellular microorganisms having a light-requirement. As used herein, the term "photosynthetic organisms" also includes organisms genetically modified by techniques well known 2o to one skilled in the art.
Referring now to figures 1 and 2, the photobioreactor (10) of the present invention comprises a container (12) for containing a liquid culture medium for cultivating photosynthetic organisms. The container (12) has a first and a second pair of 2s opposite sidewalls (14, 16). These sidewalls (14, 16) are preferably made of an inert material such as polyvinyl chloride, high-density polyethylene, low-density polyethylene and polypropylene. Advantageously, a metal framing may be added to solidify the container (12) thus formed if necessary.
The photobioreactor (10) also comprises a plurality of parallel light-emitting tubes (18) mounted within the contairrer (12) and extending in a first direction. !n this case, the light-emitting tubes extend between the first~pair ofsidewalls (14). As best viewed in figure 2, the light-emitting tubes (18) are preferably disposed in an equidistant and s offset way. The distance bEtween tire tubes (18) will depend on the selected cellular density and the desired productivity. For instance; a distance of 6 to 10 cm between the tubes (18) is suggested. Turning now to figure 5, each light-emitting tube {18) preferably consists of a casing (90) and a light source (22) inserted therein.
As used herein, the term "light source° refers-to any types of light tubes (22) which emit light t o substantially uniformly and radially along thEir length. For instance, the light tubes (22) may be neon tubes in their °off~the shelf condition which provide or not the light spectrum necessary to p~h-otosynth~sis. The casing {90) of the light-emitting tubes (18) can be made of anymaterial as long-as they are made of a transparent material, such as acrylic. However, in a situation where the photobioreactor (10) has to be 15 sterilized at elevated temperatures (for~instance up to 125 °C), it will be understood that one skilled in the art will have the knowledge to chose the suitable materials. For instance, the casing (90) of the light-emitting tubes {18) may be made of glass, whereas the container (12) may be made of stainless steel. Certain polymers which can resist to such elevated temperatures may also be used.
Although the present invention contemplates employing a light-emitting tubes (18) as defined above, a person skilled in the art will understand that the invention. is not restricted to this precise type of light-emitting tubes (18). Indeed, it is conceivable to provide a light-emitting tubes (18) which may only consist of a light tube (22). In such 2s a case, appropriate methods well known to one skilled in the art for non-permanently sealing the extremities of the light tube (22) to the container (12) n'~ay be used.
Referring again to figure 5, the casing (90) of each light-emitting tube (18) is preferably maintained within the container (12) by sealed supports (20) thus allowing 3o an access to the casing (90) of the light-emitting tubes (18) from outside the photobioreactor (10) to insertthe light source (22) therein. The casing (90) of the light-emitting tubes {18) preferably has a diameter dimensiorned so as to allow an easy insertion of the light s~unre (22). If the distance between the outer surface of the light source (22) and the inner wall ofi the casing (90) is too great, losses of lighting for the culture will occur. These losses are due to the diffraction of the light on the inner wall of the casing (90) and thus depend on the angle of incidance and on the wavelength (color) of the light beam. This phertomerran causes an undesirable conversion of light energy into thermal energy. If such a case arises, a cooling gas circulating between the light source (22) and the casing (90) may be provided to cool thre light source (22).
to Referring back to figures 1 and 2, the photobioreactor (10) further comprises cleaning means mounted withiwthe container (12) for cleaning the outer surface (26) of the light-emitting tubES (18) acrd actuatirtg~means for actuating the cleaning means preferably along~the entire lerngth ofthe light-emitting tubES (18). The mechanism of the actuating rrieans will be described further below.
The cleaning mgarrs preferably comprises a support frame (28) movable between the first pair of sidewalls (14) of~the container (12). The support-frame (28) comprises a plurality of cleaning devices (100) adapted to clean the outer surface (26) of the light-emitting tubes (18), as best shown in figure 1. It will be understood that there 2 o is at least one cleaning device (100) associated with a respective light-emitting tube (18).
In accordance with the brst preferred emb~adiment shown in figure 1, the support frame (28) comprises arne plate (30) mounted at right angles to the first direction, in 2 5 other words, the plate (30) is mounted substantially parallel to the first pair of sidewalls (14). The support frame (28) may alternatively comprise more than one plate (30), preferably two, as shown in figure 2. In both cases, the plate (30) comprises a plurality of op~errin~gs (32) each sized and shaped to receive a light-emitting tube (18). Each cleaning device (100), which is preferably a brush made of 3 o a plurality of bristles, is located in a respective opening (32). Thus, it will be understood that these openings (32) have a diameter slightly greater-than the one of the light-emitting tubes (18) in arder-to adequately fix the brush (100) on the inside edge of the opening (32). The plate (30) of the supp~art frame (28) is preferably provided with a plurality of through-holes (34), as illustrated iwfigure 1, so as to allow free passage of-the culture medium-through the plate (30), thus allowing the mixing of the culture medium whew~thE support-frame (28) is moved betweEn the first pair s of sidewalls (14). A through-hole (34) according to the present invention is not restricted to a sp~cifrc shape. For instance, the through-holes (34) may be round-, square- or oblong-shaped.
In an embodiment of the invention not illustrated, the support frame (28) of the to photobioreactor (10) could simply pest on the bottom floor of the container (12).
However, it could be advantageous to provide the photobioreactor (10) with hanging means for hanging the support frame (28) within the container (12) as shown in figures 1 and 2. Such harngirrg means, among other things, could help reducing or even preventirig the friction between the support frame (28) and the bottom floor.
15 The hanging means preferably comprise a pair of opposite support~members (36) extending longitudinally in the first direction along the second pair of sidewaHs (16).
. The hanging means also cBm~prises a pair of resting members (38) each adapted to rest on one of the suppBrt-members (36) and to rrrove along the same (36).
The support members (36) preferably comprises a rail (40) mounted along each one of 2 o the sidewalls (16). As best viewed in figure 6 in conjunction with figure 1, a first resting member (38) is provided an an ertd portion of the top side (42) of the plate (30) and a second one (38) is provided on the other end portion of the top side (42) of the plate (30). In this connection, avd in accordance with the first preferred embodiment shown in figure 1, it can be appreciated that the support-members (36) 25 may be fixed to the first and/or second pairs of sidewalk (14, 16), whereas in the case of the second preferred emb-adimr nt shown in figure 2, the ~upport members (36) are preferably fixed to the second pair of sidewalis (16).
A person skilled in the art will understand that the way by which the support 3 o members (36) and the resting members (38) are fixed to the container (12) could be achieved by gluing or welding together-the parts in question or by any other fixing means known to such person. In this corrrnection, it will be clear-that the choice of the fixing means will dep~ernd on~the materials of which the photobiore~actor is made of.
In order to adequately allowthre resting-m~emtrer (38) to move along its respective rail s (40), the resting membEr (38) is preferably provided with a roller (44), and advantageously with a set of-rollers forwrollin~g on the rail (40), as shown in Figure 2.
Moreover, it may be advantageous in certain situations to add rollers to provide a more stabilized rolling movement. In such a case, and as shown in figure 6, an additional roller (46) disposed on each errd p~artion of the top side (42) of the plate to (30) may be added in order-to sandwich the rail between the rollers (44, 46). A
person skilled in the art will krrow the appropriate way of fixing the rollers to their respective location. Such a person will also understand that the means for allowing the resting members (38) to move along its respective rail (40). is not-restricted to the use of rollers. For instawce, it is conceivable to use devices such as those allowing 15 a resting member (38) to slide along its respective rail (40). It is further conceivable to modify the configuration orthg shape of the resting member (38) so that the latter (38) be in a direct sliding relationship with its respective rail. Of course, in such cases, it is highly preferable that the surface of the device, or the resting member (38) and the rail (40), be made of materials that will facilitate a sliding movement 2 o between the parts in question. Far example, these parts could advantageously be coated with Teflon~.
As mentioned above and as shown in figures 1 and 2, the support frame (28) is moved between the first pair of sidewalls (14) with the aid of an actuating means.
2 ~ The actuating means preferably comprises a driving endless screw (50) operatively connected to the support-frame (28) and a power mEans (not shovivn) for inducing a rotation movement to the endless screw (50). As best shown in figure 6, a hollow cylinder (80) with a threaded hale, or simply a nut, is mounted to the top side (42) of the plate (30). The cylinder (80) is adapted to receive therein the driving endless 3 o screw (50) shown in figure 1, av d to interact with the same. Since this mechanism is well known, it will not be further explainE~d. As can be appreciated, the rotational movement of the endless screw (50) causes the support frame (28) to move back and forth betwe~rnthE first~pairof ~sidewalls (14). It will be understood that the power means may be any power means suitable to one skilled in the art to move the support frame in a sufficient-way. However, a particularpower means contemplated by the present invention is a reversible electric motor or a manual driving handle for s imparting the rotational movement~to the endless screw (50). Therefore, the support frame (28) from a prefen~ble slow back-acrd-forth trarrslatiorral movement, has a first role of cleaning the outersurface (26) ofthe light-emitting tubs (18).
Secondly, the support frame (28) will indirectly irrduce--the mixing of the culture medium thanks to the presence of the through-holes (32).
The movable support frame (28) may further have the task of cleaning a gas dispenser (52) extending on the bottom floor of the container (12). Indeed, the photobioreactor shown in figures 1 and 2, preferably further comprises a gas dispenser (52j far disperrsirrg gaseous COa into the culture medium, as shown in figure 4. The gas disp~errser (52) may comprise at least one dispensing tube (52) spanning generally parallel to the light-emitting tubES (18) underneath the support frame (28). The dispensing tube (52) also preferably comprises a gas inlet fog receiving C02 enriched air acrd a plurality of gas outlets for dispensing the enriched air into the camtainer. The dispensing tube (52) is preferably disposed on 2 o the bottom of the container (12) in order-to take advantage of the fact-that as the C02 is bubbled into the culture mEdium, it forces the medium to rise, thus improving substantially the mixing of the culture medium and further avoiding a strat~cation of the cultivated organisms acrd the accumulation of oxygen which would then cause a decrease of the organism production. In this connection, the suppnrt frame (28) 2 s preferably comprises brushirng mEans (54) on its bottom edge, such as a plurality of bristles, for brushing the outerwsurface ofwthe gas dispenser (52).' It will be understood that although the ph~tobioreactQr (10) ofithe present invention preferably has a rectarrgularwconfiguration (figure 1), it is recognized that any suitable 3 o shape may be used. For inetance, the present invention also contemplates employing a cylindrical-shaped or a cubic-shaped photobiareactor as shown in figure 2. For illustrative purposes only, the cubic photobioreactor may have the following dimensions : 1,2 m deep by 1,2 m of width by 1,2 m height for a total working volume of 1,7 cubic meters. In the case of a re~ctan~gular ph~atvbion=a~ctor, the suggested dimensions are :1,2 deep by 2,4 m of width by 2,4 m hEight for a working volume of 6,7 cubic meters. A person skilled in the art~will understand that the working culture s volume of the photobiarea~ctor (10) can easily be increased by simplymvditying the dimensions of its components. Such modifications do not in any way affect the performance or operation of the ph~atobioreactor (10) of the present invention.
According to another-aspgct of the present invention arnl as shown in figures 7 and l 0 8, a process far producing photosynthetic organisrrrs is proposed. This process comprises the steps of a) cultivating a photosynthetic organism in a photobiorea~ctor (10) as defined atrove, anti thereby obtaining a liquid culture medium containing photosynthetic organisms; b) renrwing from~the photobioreactor (10) a portion of the liquid culture medium; and c) separating-the liquid culture medium of step b) into a is solid phase containing the photosynthetic organisms arid a liquid phase.
In step b), the liquid culture medium is preferably pumped out from the photobioreactor (10) by rrreans of a conventional pump. The flow rate of the pumped liquid culture medium depends owthe cellular density inside the photobioreactor (10).
2 o The higher the flow is, the mare the productivity will be high. A
suggested pumping flow rate ranges between 1 and 2 volumes of liquid culture medium per working volume of the photobioreactor (10) per day.
The separating process (60) of step c) is preferably filtration, flocculation, 2s sedimentation or centrifugation process. In general, the present invention preferably contemplates employing a filter (60), and the separation efficiency rnrill thus depend on the size of the cultivated arg~anisms in relation to the size ofithe filter's pores. For nonfilamentous organisms that are difficult to filter continuously, the following separation pracessES are suggested: flocculation, sedimentation or-centrifugation.
3 o A preferable separation efficiency is obtained when over 90% of the organisms of the pumped liquid culture medium is extracted.
As shown in figure 8, the process further~preferably c~mpris~es the step of producing a solution of bicarbonate ions and hydrogen ions in a bioreaLtvr (62) such as the one described in the international application WO 98155210 in the name of the applicant.
Such a bioreactor (62) corrrprisgs a reaction chamber (64) containing immobilized carbonic anhydrase or analog thereof capable of catalyzing the hydration of dissolved C02 into bicarbarrates ions and hydrogen ions. The process preferably further comprises the step of feeding the photobioreactor (10) with the solution of bicarbonates ions arrd hydrogen ions produced in the bioreactor (62).
to in this case, the process further preferably comprises the step of feeding the bioreactor (62) with the liquid phase obtainEd in step c) described above. In other words, the liquid phase obtained fromwthE separation of the liquid culture medium coming from the photobioreactor (10) could advantageously be fed into the i bioreactor (62)~as a source of liquid.
In the process, liquid can be lost, forexample, by evaporation. Liquid can also be lost during the separation pn~cess. In order~to compensate far these liquid losts and to maintain the concentration of the nutriments, the process further preferably comprises the step of adding to the solution of bicarb~orrate ions acrd hydrogen ions 2 o a concentrate of liquid culture medium (66), thereby forming a liquid solution containing the added liquid culture medium and the bicarbonate and hydrogen ions.
A person skilled in the art will understand that such concentrate of liquid culture medium corrres from a source otherthan-the liquid phase obtained in-the above step c). This person of the art will also understand that in order to obtain a homogenous 2 s liquid solution, the process of the invention advantageously further has a step of mixing the liquid solution by means of a mixing unit (72). For instance, the mixing unit (72) is preferably a converttiorral stirrer but it could be any other stirring device known to one skilled in the art. Eventhnugh, the present invention preferably adds the concentrate of liquid culture medium to the solution of bicarbonate ions and 3 o hydrogen ions, it is conceivable to directly add said concentrate to the liquid culture medium of the photobioreactor (10). The person in the art will further understand that the liquid solution could be obtained in a slightly different way. For instance, the liquid phase obtained in step c) could bypass-the bioreactor (62), and altem~atively be fed into the mixing unit (72) so as to mix aitogether~the liquid phase, the concentrate of liquid culture medium arnd the solution of bicarbonates ions and hydrogen ions produced in the biorea~ctor (62). In such a case, the source of liquid ofwthe bioreactor (62) would have to be provided by other~means.
The required feeding rate of said concentrate (66) and the proportion of each nutriment present are determined by the analysis of the liquid culture medium present in the phvtobiorea~ctor (10) and/or by analyzing the pn~duced organism. The 1 o concentrate of culture medium (66) is preferably prepared from low quality mineral salts. The contaminants found in the concentrate (66) such as nitrates, iron, sulfur, zinc, copper, will be used far~the organism's growth. Some of the gas contaminants will also be used. This will advantageously decrease the manufacturing costs of the medium. It will also allow the culture medium used in the process to be recycled.
The process further~preferably comprises, priar~to feeding the liquid solution into the photobioreactor (10), the step of feeding the liquid solution into a heat exchanger (68) for recovering heat from the liquid phase and cooling the same. Moreover, in order to complement this cooling step, and as illustrated in figure 2, the 2o photobioreactor (10) of the present invention is preferably provided with at least one cooling tube (70) so as to allow any suitable coolant known to onE skilled in the art to flow therein. The cooling tube (70) has an inlet (88) forre~ceiving a coolant and an outlet (not visible) for releasing the same. The cooling tube (70) is preferably disposed between the light-emitting tubes (18). As it will be apparent to one skilled in the art, a casing (90) could be adapted to serve as a cooling tube (70).
Such a person in the art will also understand that the cooling tube (70) is' advantageously connected to a system that will feed the inlet (88) with a suitable coolant and recirculate the same into the cooling tube (70) for a predefirned period of time. Since this kind of system is already known, it will not be described further.
Referring to figures 2 and 3, in orderto carry out the above described process, the present invention further proposes a culture unit (110) for cultivating photosynthetic organisms. The culture unit (110) of the present invention is able to fulfill mainly two roles, namely the culture of photosynthetic organisms and the production of bicarbonate ions as a source of carbon for the growth of the photosynthetic organisms. Therefore, the culture unit (110) of the invention allows the photosynthetic organisms to bE cultivated in continuous.
As schematically illustrated in figure 8, the culture unit (110) comprises a photobioreactor (10) for cultivating photosynthetic organisms in a liquid culture medium. Such a photobiQreactar (10) may be any type of photobiorea~ctor, however, to the present inventionprefers employing a~photobioreactor (10) described above and shown in figures 1 and 2.
The culture unit (110) also comprises a bioreactor (62) for producing bicarbonate i ions and hydrogen ions from a COz-containing gas. As mentioned above, the 15 bioreactor (62) comprisES a reaction chamber (64) cvntainirrg immobilized carbonic anhydrase or analog thereof capable of catalyzing the hydration of dissolved into the bicarbonate ions arrd hydrogen ions. The bioreactor (62) will advantageously allow a reduction in the time required to catalyze th~e~tr~nsfamration of the COZ into the bicarbonate ions and hydrogen ions. Consequently, the use of the bioreactor (62) 2 o helps reducing the size of the e~quip~mentwrequired . It also helps increasing the C02 absorption efficacy.
The bioreactor (62) comprises a liquid inlet (120) in fluid communication with the reaction chamber (64) far~receiving a liquid, a gas inlet (120) in fluid communication 2 5 with the reaction chamber (64) for receiving a COZ-containing gas, and a liquid outlet (122) in fluid communication with the reaction chamber (64) for dispensing a solution containing the bicarbonate ions and hydrogen ions.
The culture unit (110) of the present invention further comprises means for 3 o transferring the solution of bicarbonate ions and hydrogen ions dispensed from the liquid outlet (122) to the ptrotobioreactor (10). For example, a pipe system including a pump, or any otherwsuitable mBans known to a person skilled in the art could be used.
The culture unit (110) preferably comprises means, such as a pump, for removing s a portion of the liquid culture from the photobioreactor (10) and means (60) for separating the removed portion of liquid culture into a liquid phase and into a solid phase which cantairrs-the organisms. As~m~entioned above, the separating means is preferably a filter but depending crn the type of organisms to grow, other separating means known to ante skilled in the art~may be used. The culture unit (110) preferably l o further comprises meartswfartransferring-thE liquid phasE produced in the filter (60) into the liquid inlet (120) of the bioreactar (62). For irrstarr~, the liquid phase may be manually transferred to the biarEactor (62) with the use of suitable tools well known by one skilled in the art. Altem~atively, the liquid phase could be transferred to the bioreactor (62j with the aid of gravity. Indeed, by placing the filter (60) at a level 15 substantially higher that the one of the bioreactor (62), the liquid phase can be gravity fed into the bioreactor (62).
Furthermore, the culture unit (110) preferably comprises means far adding to the solution of bicarbonate ions arnd hydrogen ions a concentrate of liquid culture 2 o medium. For instance, the concentrate of liquid culture medium can be added to the solution of bicarbonate ions and hydrogen ions by way of manual or gravitational means such as those explairred above. Moreover, the culture unit (110) preferably comprises a mixing unit (72), such as a conventional stirrer, for mixing the concentrate of liquid culture medium with the solution of bicarbvrnate ions and 25 hydrogen ions so as towform a liquid solution. As it will be clearfor a person in the art, the liquid solution can be abtairred by directly adding the concentrate of liquid culture medium to the solution of bicarbonate ions and hydrogen ions. Alternatively, the concentrate of liquid culture medium and the solution of bicarbonate ions and hydrogen ions can be fed directly to the mixing unit (72) to farm the liquid solution.
The culture unit (110) preferably further-comprises means, such as a heat exchanger for recovering heat (68) from the liquid solution arid cooling the same.
Finally, the culture unit (110) preferablyfurther-comprises means, such as a pump or any other suitable means fvr-trarrsfemrrg-thE liquid solution to the phvtobivreactor (10).
EXAMPLE
The following example is illustrative of the wide rarnge of applicability of the present invention and is not intended to limit its scope. Modifications ant!
variations can be made therein without departing-from~the spirit and scope of the invention.
l o Even though the process of the invention as described previously uses only one photobioreactor (10), it will be clear to one skilled in the art from the following example that it is conceivable to use mare than one photobivreactor (10) so as to greatly increase.the production capacity vf~the process contemplated by the present invention.
Therefore, a series of fifty (50) photobioreactors of 7,0 m3 can be user! for the growth of the microalgae Spirulina plaferrsis and for the processing of carbonated water resulting from a bioreactor (62). These photobioreactars (10) are disposed side by side with respE~ct to the second pair of sidewalls (1fi). Light tubes (22) of the type 2 o Cool White of 80 W are used as a light source. The working volume of each photobioreactor (10) is about 3,1 m3. One hundred twenty height (128) light tubes per photobioreactor will contribute-to maintaiwthe temperature of the medium at around 36°C and to provide the necessary sourcE of light.
Spirulina platensis is cultivated in a suitable medium. The desired cellular density is about 0,6 gram of algae biomass per liter of culture medium. A wbrking volume of about 3,1 m3 will produce more than 250 kilograms of dry bivmass per day. This biomass could be used as a pnzphylactic agent in the poultry nutrition.
3 o Although preferred embodiments of-the presEnt invention have been described in detail herein and illustrated in-tlre accompanying drawings, it is to be understood that the invention is not iimitet! to these precise embodiments and that various changes ze and modificatir~ns maybe eff~cfied-thre~rein without departing from the-scope or spirit of the present invention.
t o Thanks to the cleaningmeans provided within the container and the actuating means for actuating the same, it is possible withwthe present invention to easily get rid of the cultivated organisms which mray block the light source by adhering to the same.
Also, the simplicity of its concept rrrakes it a very attractive and easy tool to be used for growing a desired organism at a substantially low cost.
is According to another aspect of the invention, there is provided a culture unit for cultivating photosynthetic organisms, cam~prising a photobioreactor for cultivating a photosynthetic organism in a liquid culture medium and a bioreactorfor producing bicarbonate ions and hydrogen ions from a C02-containing gas, the bioreactor 2 o comprising:
- a reaction chamber containing immobilized carbonic anhydrase or analog thev~of caprable of catalyzing the hydration of dissolved CO2 into the bicarbonates ions and hydrogen ions, - a liquid inlet in fluid communication with the reaction chamber, for 2 s receiving a liquid, - . a gas inlet in fluid communication with the reaction chamber, for receiving a C02 -containing gas; and - a liquid outlet in fluid communication with the reaction chamber, for dispensing a liquid solution containing the bicarbonates ions and 3 o hydrogen ions.
The culture unit furtherwcomprises meanswfor~transferring the solution of bicarbonates ions and hydn~gen ions dispensed from~the liquid outlet to the photobioreactor.
As can be appreciated, orre advantage of a culture unit as defined above is that it allows the use, at low cost, ofi bicarbonate ions as the source of carbon necessary for the growth of the organisms. Also, thanks to the use of a COZ-containing gas in s the bioreactor, the unit has the advantage of reducing C02 contained in the air.
Consequently, it also helps reducing the greenhouse effect mentioned above.
The invention also proposes a pracess-for-prvducirng photosynthetic organisms, the process comprising the steps of:
1 o a) cultivating a photosynthetic organism in a photobioreactor as defined above, and thereby obtaining a liquid culture medium containing photosynthetic organisms;
b) removing from~the phvtobioreactor-a portion of the liquid culture medium;
and I~
is c) separating the liquid culture medium of step b) into a solid phase containing the photosynthetic organisms acrd a liquid phase.
BI~IEF~DE5C~fPTI~iN OF'-THE~DRAWINGS
These and other objects and advantages of~the invention will bECame apparent upon reading the detailed description and upon referring to the drawings in which Figure 1 is a perspective view of a photobioreactor according to a first preferred embodiment of the invenfiion, with one side wall removed to better see the inside of 2 s the photobiareactor.
Figure 2 is a perspective view of a photobioreactar~according to a second preferred embodiment of the invention.
Figure 3 is a top view of thwphotobiorea~ctar of figure 2.
Figure 4 is a cross-sectional side view taken along the line A-A of figure 3.
Figure 5 is an enlarged view of section B of figure 4.
Figure 6 is an exploded view of~thE support frame of the photobian=actor of figure s Figure 7 is a schematic flow chart of a first preferred variant of the process for producing photosynthetic organisms according to the present invention; and Figure 8 is a schematic flow chart of a second prefemad variant of the process for producing photosynthEtic organisms accordirng to the present invention.
~. o DESC~(PTI~(3N ~~PREFERRED EIffiBQDIIVIENTS
As shown in the drawings and in accordance with a first aspect of the invention, a is photobioreactor for cultivating photosynthetic organisms is proposed. The photobioreactor of the invention is suitable for the culture of any kind of photosynthetic organism, such as plant cells and unicellular or multicellular microorganisms having a light-requirement. As used herein, the term "photosynthetic organisms" also includes organisms genetically modified by techniques well known 2o to one skilled in the art.
Referring now to figures 1 and 2, the photobioreactor (10) of the present invention comprises a container (12) for containing a liquid culture medium for cultivating photosynthetic organisms. The container (12) has a first and a second pair of 2s opposite sidewalls (14, 16). These sidewalls (14, 16) are preferably made of an inert material such as polyvinyl chloride, high-density polyethylene, low-density polyethylene and polypropylene. Advantageously, a metal framing may be added to solidify the container (12) thus formed if necessary.
The photobioreactor (10) also comprises a plurality of parallel light-emitting tubes (18) mounted within the contairrer (12) and extending in a first direction. !n this case, the light-emitting tubes extend between the first~pair ofsidewalls (14). As best viewed in figure 2, the light-emitting tubes (18) are preferably disposed in an equidistant and s offset way. The distance bEtween tire tubes (18) will depend on the selected cellular density and the desired productivity. For instance; a distance of 6 to 10 cm between the tubes (18) is suggested. Turning now to figure 5, each light-emitting tube {18) preferably consists of a casing (90) and a light source (22) inserted therein.
As used herein, the term "light source° refers-to any types of light tubes (22) which emit light t o substantially uniformly and radially along thEir length. For instance, the light tubes (22) may be neon tubes in their °off~the shelf condition which provide or not the light spectrum necessary to p~h-otosynth~sis. The casing {90) of the light-emitting tubes (18) can be made of anymaterial as long-as they are made of a transparent material, such as acrylic. However, in a situation where the photobioreactor (10) has to be 15 sterilized at elevated temperatures (for~instance up to 125 °C), it will be understood that one skilled in the art will have the knowledge to chose the suitable materials. For instance, the casing (90) of the light-emitting tubes {18) may be made of glass, whereas the container (12) may be made of stainless steel. Certain polymers which can resist to such elevated temperatures may also be used.
Although the present invention contemplates employing a light-emitting tubes (18) as defined above, a person skilled in the art will understand that the invention. is not restricted to this precise type of light-emitting tubes (18). Indeed, it is conceivable to provide a light-emitting tubes (18) which may only consist of a light tube (22). In such 2s a case, appropriate methods well known to one skilled in the art for non-permanently sealing the extremities of the light tube (22) to the container (12) n'~ay be used.
Referring again to figure 5, the casing (90) of each light-emitting tube (18) is preferably maintained within the container (12) by sealed supports (20) thus allowing 3o an access to the casing (90) of the light-emitting tubes (18) from outside the photobioreactor (10) to insertthe light source (22) therein. The casing (90) of the light-emitting tubes {18) preferably has a diameter dimensiorned so as to allow an easy insertion of the light s~unre (22). If the distance between the outer surface of the light source (22) and the inner wall ofi the casing (90) is too great, losses of lighting for the culture will occur. These losses are due to the diffraction of the light on the inner wall of the casing (90) and thus depend on the angle of incidance and on the wavelength (color) of the light beam. This phertomerran causes an undesirable conversion of light energy into thermal energy. If such a case arises, a cooling gas circulating between the light source (22) and the casing (90) may be provided to cool thre light source (22).
to Referring back to figures 1 and 2, the photobioreactor (10) further comprises cleaning means mounted withiwthe container (12) for cleaning the outer surface (26) of the light-emitting tubES (18) acrd actuatirtg~means for actuating the cleaning means preferably along~the entire lerngth ofthe light-emitting tubES (18). The mechanism of the actuating rrieans will be described further below.
The cleaning mgarrs preferably comprises a support frame (28) movable between the first pair of sidewalls (14) of~the container (12). The support-frame (28) comprises a plurality of cleaning devices (100) adapted to clean the outer surface (26) of the light-emitting tubes (18), as best shown in figure 1. It will be understood that there 2 o is at least one cleaning device (100) associated with a respective light-emitting tube (18).
In accordance with the brst preferred emb~adiment shown in figure 1, the support frame (28) comprises arne plate (30) mounted at right angles to the first direction, in 2 5 other words, the plate (30) is mounted substantially parallel to the first pair of sidewalls (14). The support frame (28) may alternatively comprise more than one plate (30), preferably two, as shown in figure 2. In both cases, the plate (30) comprises a plurality of op~errin~gs (32) each sized and shaped to receive a light-emitting tube (18). Each cleaning device (100), which is preferably a brush made of 3 o a plurality of bristles, is located in a respective opening (32). Thus, it will be understood that these openings (32) have a diameter slightly greater-than the one of the light-emitting tubes (18) in arder-to adequately fix the brush (100) on the inside edge of the opening (32). The plate (30) of the supp~art frame (28) is preferably provided with a plurality of through-holes (34), as illustrated iwfigure 1, so as to allow free passage of-the culture medium-through the plate (30), thus allowing the mixing of the culture medium whew~thE support-frame (28) is moved betweEn the first pair s of sidewalls (14). A through-hole (34) according to the present invention is not restricted to a sp~cifrc shape. For instance, the through-holes (34) may be round-, square- or oblong-shaped.
In an embodiment of the invention not illustrated, the support frame (28) of the to photobioreactor (10) could simply pest on the bottom floor of the container (12).
However, it could be advantageous to provide the photobioreactor (10) with hanging means for hanging the support frame (28) within the container (12) as shown in figures 1 and 2. Such harngirrg means, among other things, could help reducing or even preventirig the friction between the support frame (28) and the bottom floor.
15 The hanging means preferably comprise a pair of opposite support~members (36) extending longitudinally in the first direction along the second pair of sidewaHs (16).
. The hanging means also cBm~prises a pair of resting members (38) each adapted to rest on one of the suppBrt-members (36) and to rrrove along the same (36).
The support members (36) preferably comprises a rail (40) mounted along each one of 2 o the sidewalls (16). As best viewed in figure 6 in conjunction with figure 1, a first resting member (38) is provided an an ertd portion of the top side (42) of the plate (30) and a second one (38) is provided on the other end portion of the top side (42) of the plate (30). In this connection, avd in accordance with the first preferred embodiment shown in figure 1, it can be appreciated that the support-members (36) 25 may be fixed to the first and/or second pairs of sidewalk (14, 16), whereas in the case of the second preferred emb-adimr nt shown in figure 2, the ~upport members (36) are preferably fixed to the second pair of sidewalis (16).
A person skilled in the art will understand that the way by which the support 3 o members (36) and the resting members (38) are fixed to the container (12) could be achieved by gluing or welding together-the parts in question or by any other fixing means known to such person. In this corrrnection, it will be clear-that the choice of the fixing means will dep~ernd on~the materials of which the photobiore~actor is made of.
In order to adequately allowthre resting-m~emtrer (38) to move along its respective rail s (40), the resting membEr (38) is preferably provided with a roller (44), and advantageously with a set of-rollers forwrollin~g on the rail (40), as shown in Figure 2.
Moreover, it may be advantageous in certain situations to add rollers to provide a more stabilized rolling movement. In such a case, and as shown in figure 6, an additional roller (46) disposed on each errd p~artion of the top side (42) of the plate to (30) may be added in order-to sandwich the rail between the rollers (44, 46). A
person skilled in the art will krrow the appropriate way of fixing the rollers to their respective location. Such a person will also understand that the means for allowing the resting members (38) to move along its respective rail (40). is not-restricted to the use of rollers. For instawce, it is conceivable to use devices such as those allowing 15 a resting member (38) to slide along its respective rail (40). It is further conceivable to modify the configuration orthg shape of the resting member (38) so that the latter (38) be in a direct sliding relationship with its respective rail. Of course, in such cases, it is highly preferable that the surface of the device, or the resting member (38) and the rail (40), be made of materials that will facilitate a sliding movement 2 o between the parts in question. Far example, these parts could advantageously be coated with Teflon~.
As mentioned above and as shown in figures 1 and 2, the support frame (28) is moved between the first pair of sidewalls (14) with the aid of an actuating means.
2 ~ The actuating means preferably comprises a driving endless screw (50) operatively connected to the support-frame (28) and a power mEans (not shovivn) for inducing a rotation movement to the endless screw (50). As best shown in figure 6, a hollow cylinder (80) with a threaded hale, or simply a nut, is mounted to the top side (42) of the plate (30). The cylinder (80) is adapted to receive therein the driving endless 3 o screw (50) shown in figure 1, av d to interact with the same. Since this mechanism is well known, it will not be further explainE~d. As can be appreciated, the rotational movement of the endless screw (50) causes the support frame (28) to move back and forth betwe~rnthE first~pairof ~sidewalls (14). It will be understood that the power means may be any power means suitable to one skilled in the art to move the support frame in a sufficient-way. However, a particularpower means contemplated by the present invention is a reversible electric motor or a manual driving handle for s imparting the rotational movement~to the endless screw (50). Therefore, the support frame (28) from a prefen~ble slow back-acrd-forth trarrslatiorral movement, has a first role of cleaning the outersurface (26) ofthe light-emitting tubs (18).
Secondly, the support frame (28) will indirectly irrduce--the mixing of the culture medium thanks to the presence of the through-holes (32).
The movable support frame (28) may further have the task of cleaning a gas dispenser (52) extending on the bottom floor of the container (12). Indeed, the photobioreactor shown in figures 1 and 2, preferably further comprises a gas dispenser (52j far disperrsirrg gaseous COa into the culture medium, as shown in figure 4. The gas disp~errser (52) may comprise at least one dispensing tube (52) spanning generally parallel to the light-emitting tubES (18) underneath the support frame (28). The dispensing tube (52) also preferably comprises a gas inlet fog receiving C02 enriched air acrd a plurality of gas outlets for dispensing the enriched air into the camtainer. The dispensing tube (52) is preferably disposed on 2 o the bottom of the container (12) in order-to take advantage of the fact-that as the C02 is bubbled into the culture mEdium, it forces the medium to rise, thus improving substantially the mixing of the culture medium and further avoiding a strat~cation of the cultivated organisms acrd the accumulation of oxygen which would then cause a decrease of the organism production. In this connection, the suppnrt frame (28) 2 s preferably comprises brushirng mEans (54) on its bottom edge, such as a plurality of bristles, for brushing the outerwsurface ofwthe gas dispenser (52).' It will be understood that although the ph~tobioreactQr (10) ofithe present invention preferably has a rectarrgularwconfiguration (figure 1), it is recognized that any suitable 3 o shape may be used. For inetance, the present invention also contemplates employing a cylindrical-shaped or a cubic-shaped photobiareactor as shown in figure 2. For illustrative purposes only, the cubic photobioreactor may have the following dimensions : 1,2 m deep by 1,2 m of width by 1,2 m height for a total working volume of 1,7 cubic meters. In the case of a re~ctan~gular ph~atvbion=a~ctor, the suggested dimensions are :1,2 deep by 2,4 m of width by 2,4 m hEight for a working volume of 6,7 cubic meters. A person skilled in the art~will understand that the working culture s volume of the photobiarea~ctor (10) can easily be increased by simplymvditying the dimensions of its components. Such modifications do not in any way affect the performance or operation of the ph~atobioreactor (10) of the present invention.
According to another-aspgct of the present invention arnl as shown in figures 7 and l 0 8, a process far producing photosynthetic organisrrrs is proposed. This process comprises the steps of a) cultivating a photosynthetic organism in a photobiorea~ctor (10) as defined atrove, anti thereby obtaining a liquid culture medium containing photosynthetic organisms; b) renrwing from~the photobioreactor (10) a portion of the liquid culture medium; and c) separating-the liquid culture medium of step b) into a is solid phase containing the photosynthetic organisms arid a liquid phase.
In step b), the liquid culture medium is preferably pumped out from the photobioreactor (10) by rrreans of a conventional pump. The flow rate of the pumped liquid culture medium depends owthe cellular density inside the photobioreactor (10).
2 o The higher the flow is, the mare the productivity will be high. A
suggested pumping flow rate ranges between 1 and 2 volumes of liquid culture medium per working volume of the photobioreactor (10) per day.
The separating process (60) of step c) is preferably filtration, flocculation, 2s sedimentation or centrifugation process. In general, the present invention preferably contemplates employing a filter (60), and the separation efficiency rnrill thus depend on the size of the cultivated arg~anisms in relation to the size ofithe filter's pores. For nonfilamentous organisms that are difficult to filter continuously, the following separation pracessES are suggested: flocculation, sedimentation or-centrifugation.
3 o A preferable separation efficiency is obtained when over 90% of the organisms of the pumped liquid culture medium is extracted.
As shown in figure 8, the process further~preferably c~mpris~es the step of producing a solution of bicarbonate ions and hydrogen ions in a bioreaLtvr (62) such as the one described in the international application WO 98155210 in the name of the applicant.
Such a bioreactor (62) corrrprisgs a reaction chamber (64) containing immobilized carbonic anhydrase or analog thereof capable of catalyzing the hydration of dissolved C02 into bicarbarrates ions and hydrogen ions. The process preferably further comprises the step of feeding the photobioreactor (10) with the solution of bicarbonates ions arrd hydrogen ions produced in the bioreactor (62).
to in this case, the process further preferably comprises the step of feeding the bioreactor (62) with the liquid phase obtainEd in step c) described above. In other words, the liquid phase obtained fromwthE separation of the liquid culture medium coming from the photobioreactor (10) could advantageously be fed into the i bioreactor (62)~as a source of liquid.
In the process, liquid can be lost, forexample, by evaporation. Liquid can also be lost during the separation pn~cess. In order~to compensate far these liquid losts and to maintain the concentration of the nutriments, the process further preferably comprises the step of adding to the solution of bicarb~orrate ions acrd hydrogen ions 2 o a concentrate of liquid culture medium (66), thereby forming a liquid solution containing the added liquid culture medium and the bicarbonate and hydrogen ions.
A person skilled in the art will understand that such concentrate of liquid culture medium corrres from a source otherthan-the liquid phase obtained in-the above step c). This person of the art will also understand that in order to obtain a homogenous 2 s liquid solution, the process of the invention advantageously further has a step of mixing the liquid solution by means of a mixing unit (72). For instance, the mixing unit (72) is preferably a converttiorral stirrer but it could be any other stirring device known to one skilled in the art. Eventhnugh, the present invention preferably adds the concentrate of liquid culture medium to the solution of bicarbonate ions and 3 o hydrogen ions, it is conceivable to directly add said concentrate to the liquid culture medium of the photobioreactor (10). The person in the art will further understand that the liquid solution could be obtained in a slightly different way. For instance, the liquid phase obtained in step c) could bypass-the bioreactor (62), and altem~atively be fed into the mixing unit (72) so as to mix aitogether~the liquid phase, the concentrate of liquid culture medium arnd the solution of bicarbonates ions and hydrogen ions produced in the biorea~ctor (62). In such a case, the source of liquid ofwthe bioreactor (62) would have to be provided by other~means.
The required feeding rate of said concentrate (66) and the proportion of each nutriment present are determined by the analysis of the liquid culture medium present in the phvtobiorea~ctor (10) and/or by analyzing the pn~duced organism. The 1 o concentrate of culture medium (66) is preferably prepared from low quality mineral salts. The contaminants found in the concentrate (66) such as nitrates, iron, sulfur, zinc, copper, will be used far~the organism's growth. Some of the gas contaminants will also be used. This will advantageously decrease the manufacturing costs of the medium. It will also allow the culture medium used in the process to be recycled.
The process further~preferably comprises, priar~to feeding the liquid solution into the photobioreactor (10), the step of feeding the liquid solution into a heat exchanger (68) for recovering heat from the liquid phase and cooling the same. Moreover, in order to complement this cooling step, and as illustrated in figure 2, the 2o photobioreactor (10) of the present invention is preferably provided with at least one cooling tube (70) so as to allow any suitable coolant known to onE skilled in the art to flow therein. The cooling tube (70) has an inlet (88) forre~ceiving a coolant and an outlet (not visible) for releasing the same. The cooling tube (70) is preferably disposed between the light-emitting tubes (18). As it will be apparent to one skilled in the art, a casing (90) could be adapted to serve as a cooling tube (70).
Such a person in the art will also understand that the cooling tube (70) is' advantageously connected to a system that will feed the inlet (88) with a suitable coolant and recirculate the same into the cooling tube (70) for a predefirned period of time. Since this kind of system is already known, it will not be described further.
Referring to figures 2 and 3, in orderto carry out the above described process, the present invention further proposes a culture unit (110) for cultivating photosynthetic organisms. The culture unit (110) of the present invention is able to fulfill mainly two roles, namely the culture of photosynthetic organisms and the production of bicarbonate ions as a source of carbon for the growth of the photosynthetic organisms. Therefore, the culture unit (110) of the invention allows the photosynthetic organisms to bE cultivated in continuous.
As schematically illustrated in figure 8, the culture unit (110) comprises a photobioreactor (10) for cultivating photosynthetic organisms in a liquid culture medium. Such a photobiQreactar (10) may be any type of photobiorea~ctor, however, to the present inventionprefers employing a~photobioreactor (10) described above and shown in figures 1 and 2.
The culture unit (110) also comprises a bioreactor (62) for producing bicarbonate i ions and hydrogen ions from a COz-containing gas. As mentioned above, the 15 bioreactor (62) comprisES a reaction chamber (64) cvntainirrg immobilized carbonic anhydrase or analog thereof capable of catalyzing the hydration of dissolved into the bicarbonate ions arrd hydrogen ions. The bioreactor (62) will advantageously allow a reduction in the time required to catalyze th~e~tr~nsfamration of the COZ into the bicarbonate ions and hydrogen ions. Consequently, the use of the bioreactor (62) 2 o helps reducing the size of the e~quip~mentwrequired . It also helps increasing the C02 absorption efficacy.
The bioreactor (62) comprises a liquid inlet (120) in fluid communication with the reaction chamber (64) far~receiving a liquid, a gas inlet (120) in fluid communication 2 5 with the reaction chamber (64) for receiving a COZ-containing gas, and a liquid outlet (122) in fluid communication with the reaction chamber (64) for dispensing a solution containing the bicarbonate ions and hydrogen ions.
The culture unit (110) of the present invention further comprises means for 3 o transferring the solution of bicarbonate ions and hydrogen ions dispensed from the liquid outlet (122) to the ptrotobioreactor (10). For example, a pipe system including a pump, or any otherwsuitable mBans known to a person skilled in the art could be used.
The culture unit (110) preferably comprises means, such as a pump, for removing s a portion of the liquid culture from the photobioreactor (10) and means (60) for separating the removed portion of liquid culture into a liquid phase and into a solid phase which cantairrs-the organisms. As~m~entioned above, the separating means is preferably a filter but depending crn the type of organisms to grow, other separating means known to ante skilled in the art~may be used. The culture unit (110) preferably l o further comprises meartswfartransferring-thE liquid phasE produced in the filter (60) into the liquid inlet (120) of the bioreactar (62). For irrstarr~, the liquid phase may be manually transferred to the biarEactor (62) with the use of suitable tools well known by one skilled in the art. Altem~atively, the liquid phase could be transferred to the bioreactor (62j with the aid of gravity. Indeed, by placing the filter (60) at a level 15 substantially higher that the one of the bioreactor (62), the liquid phase can be gravity fed into the bioreactor (62).
Furthermore, the culture unit (110) preferably comprises means far adding to the solution of bicarbonate ions arnd hydrogen ions a concentrate of liquid culture 2 o medium. For instance, the concentrate of liquid culture medium can be added to the solution of bicarbonate ions and hydrogen ions by way of manual or gravitational means such as those explairred above. Moreover, the culture unit (110) preferably comprises a mixing unit (72), such as a conventional stirrer, for mixing the concentrate of liquid culture medium with the solution of bicarbvrnate ions and 25 hydrogen ions so as towform a liquid solution. As it will be clearfor a person in the art, the liquid solution can be abtairred by directly adding the concentrate of liquid culture medium to the solution of bicarbonate ions and hydrogen ions. Alternatively, the concentrate of liquid culture medium and the solution of bicarbonate ions and hydrogen ions can be fed directly to the mixing unit (72) to farm the liquid solution.
The culture unit (110) preferably further-comprises means, such as a heat exchanger for recovering heat (68) from the liquid solution arid cooling the same.
Finally, the culture unit (110) preferablyfurther-comprises means, such as a pump or any other suitable means fvr-trarrsfemrrg-thE liquid solution to the phvtobivreactor (10).
EXAMPLE
The following example is illustrative of the wide rarnge of applicability of the present invention and is not intended to limit its scope. Modifications ant!
variations can be made therein without departing-from~the spirit and scope of the invention.
l o Even though the process of the invention as described previously uses only one photobioreactor (10), it will be clear to one skilled in the art from the following example that it is conceivable to use mare than one photobivreactor (10) so as to greatly increase.the production capacity vf~the process contemplated by the present invention.
Therefore, a series of fifty (50) photobioreactors of 7,0 m3 can be user! for the growth of the microalgae Spirulina plaferrsis and for the processing of carbonated water resulting from a bioreactor (62). These photobioreactars (10) are disposed side by side with respE~ct to the second pair of sidewalls (1fi). Light tubes (22) of the type 2 o Cool White of 80 W are used as a light source. The working volume of each photobioreactor (10) is about 3,1 m3. One hundred twenty height (128) light tubes per photobioreactor will contribute-to maintaiwthe temperature of the medium at around 36°C and to provide the necessary sourcE of light.
Spirulina platensis is cultivated in a suitable medium. The desired cellular density is about 0,6 gram of algae biomass per liter of culture medium. A wbrking volume of about 3,1 m3 will produce more than 250 kilograms of dry bivmass per day. This biomass could be used as a pnzphylactic agent in the poultry nutrition.
3 o Although preferred embodiments of-the presEnt invention have been described in detail herein and illustrated in-tlre accompanying drawings, it is to be understood that the invention is not iimitet! to these precise embodiments and that various changes ze and modificatir~ns maybe eff~cfied-thre~rein without departing from the-scope or spirit of the present invention.
Claims (30)
1. A photobioreactor comprising:
-a container for containing a liquid culture medium for cultivating photosynthetic organisms, -a plurality of parallel light-emitting tubes mounted within the container and extending in a first direction, each light-emitting tube having an outer surface;
-cleaning means mounted within the container-for cleaning the outer surface of the light-emitting tubes; and -actuating means for actuating the cleaning means.
-a container for containing a liquid culture medium for cultivating photosynthetic organisms, -a plurality of parallel light-emitting tubes mounted within the container and extending in a first direction, each light-emitting tube having an outer surface;
-cleaning means mounted within the container-for cleaning the outer surface of the light-emitting tubes; and -actuating means for actuating the cleaning means.
2. A photobioreactoras claimed in claim 1, wherein the cleaning means comprises a support framing movable in said first direction, the support frame comprising a plurality of cleaning devices adapted to clean said outer surface of the light-emitting tubes, each of said cleaning devices being associated with a respective one of said light-emitting tubes.
3. A photobioreactor as claimed in claim 2, wherein the support frame comprises at least one plate mounted at right angle to the first direction, said at least one plate comprising a plurality of openings each sized and shaped to receive a respective one of said light-emitting tubes, and each of said cleaning devices being located in a respective one of said openings.
4. A photobioreactor as claimed in claim 3, wherein each of said cleaning devices comprises a brushing means for brushing the outer surface of a respective light-emitting tube.
5. A photobioreactor as claimed in claim 4, wherein the brushing means comprises a plurality of bristles.
6. A photobioreactor as claimed in claim 3, comprising hanging means far hanging the support frame within the container.
7. A photobioreactar as claimed in claim 6, wherein:
-the container has a re~octangular configuration with a first and a second pair of opposite sidewalls, the light-emitting tubes extending between said first pair of sidewalls;
-the support frame comprises a bottom side, and a top side with two end portions, and -the hanging means comprises:
a pair of support members provided respectively on each one of said sidewalls of the second pair of sidewalls; and a pair of resting members, a first one provided on one of said end portion of the top side of the support frame and a second one provided on the other end portion of the tap side of the support frame, each of said resting members being respectively adapted to rest an one of said support members and being further movable along the support members.
-the container has a re~octangular configuration with a first and a second pair of opposite sidewalls, the light-emitting tubes extending between said first pair of sidewalls;
-the support frame comprises a bottom side, and a top side with two end portions, and -the hanging means comprises:
a pair of support members provided respectively on each one of said sidewalls of the second pair of sidewalls; and a pair of resting members, a first one provided on one of said end portion of the top side of the support frame and a second one provided on the other end portion of the tap side of the support frame, each of said resting members being respectively adapted to rest an one of said support members and being further movable along the support members.
8. A photobioreactor as claimed in claim 7, wherein said pair of support members comprises a rail mounted on each one of said sidewalls.
9. A photobioreactor as claimed in claim 8, wherein said pair of resting members comprises a roller far rolling on the rail.
10. A photobiareactor as claimed in claim 3, wherein said at least one plate of the support frame is provided with a plurality of through-holes allowing free passage of the culture medium through the plate.
11. A photobiareactor as claimed in claim 1, further comprising a gas dispenser for dispensing CO2 enriched air into the culture medium.
12. A photobioreactor claimed in claim 11, wherein the gas dispenser comprises at least one dispensing tube spanning generally parallel to the light-emitting tubes underneath the support frame, the dispensing tube comprising a gas inlet for receiving the CO2 enriched air and a plurality of gas outlet for dispensing the CO2 enriched air into the container.
13. A photobiareactor as claimed in claim 12, wherein the support-frame comprises a bottom edge comprising brushing means for brushing an outer surface of said at least one dispensing tube.
14. A photobioreactor as claimed in claim 13, wherein the brushing means comprises a plurality of bristles.
15. A photobioreactor as claimed in claim 2, wherein the actuating means comprises a driving endless screw operatively connected to the support frame and a power means for inducing a rotation movement to said endless screw, said rotation movement causing the support-frame to move in said first direction.
16. A photobiareactor as claimed in claim 15, wherein said power means is a reversible electric motor or a manual driving handle for imparting the rotation movement to said endless screw.
17. A culture unit for cultivating photosynthetic organisms, comprising:
- a photobioreactor for cultivating a photosynthetic organism in a liquid culture medium;
- a bioreactor for producing bicarbonate ions and hydrogen ions from a CO2-containing gas, the bioreactor comprising:
- a reaction chamber containing immobilized cartronic anhydrase or analog thereof-capable of catalyzing the hydration of dissolved CO2 into said bicarbonates ions and hydrogen ions, - a liquid inlet in fluid communication with the reaction chamber, for receiving a liquid, - a gas inlet in fluid communication with the reaction chamber, for receiving a CO2 -containing gas; and - a liquid outlet in fluid communication with the reaction chamber, for dispensing a solution containing said bicarbonates ions and hydrogen ions and - means for transferring said solution of bicarbonates ions and hydrogen ions dispensed from said liquid outlet to the photobioreactor.
- a photobioreactor for cultivating a photosynthetic organism in a liquid culture medium;
- a bioreactor for producing bicarbonate ions and hydrogen ions from a CO2-containing gas, the bioreactor comprising:
- a reaction chamber containing immobilized cartronic anhydrase or analog thereof-capable of catalyzing the hydration of dissolved CO2 into said bicarbonates ions and hydrogen ions, - a liquid inlet in fluid communication with the reaction chamber, for receiving a liquid, - a gas inlet in fluid communication with the reaction chamber, for receiving a CO2 -containing gas; and - a liquid outlet in fluid communication with the reaction chamber, for dispensing a solution containing said bicarbonates ions and hydrogen ions and - means for transferring said solution of bicarbonates ions and hydrogen ions dispensed from said liquid outlet to the photobioreactor.
18. A culture unit as claimed in claim 17, comprising - means for removing a portion of the liquid culture medium from the photobioreactor and - means for separating said portion of the liquid culture medium into a solid phase containing the organisms and into a liquid phase.
19. A culture unit as claimed in claim 18, comprising:
- means for-transferring the liquid phase obtained in the separating means into the liquid inlet of the bioreactor.
- means for-transferring the liquid phase obtained in the separating means into the liquid inlet of the bioreactor.
20. A culture unit as claimed in claim 19, comprising:
means for adding to said solution of bicarbonate ions and hydrogen ions a concentrate of liquid culture medium.
means for adding to said solution of bicarbonate ions and hydrogen ions a concentrate of liquid culture medium.
21. A culture unit as claimed in claim 20, comprising:
- a mixing unit for mixing said concentrate of liquid culture medium with the solution of bicarbonate ions and hydrogen ions so as to obtain a liquid solution.
- a mixing unit for mixing said concentrate of liquid culture medium with the solution of bicarbonate ions and hydrogen ions so as to obtain a liquid solution.
22. A culture unit as claimed in claim 21, comprising - means for recovering heat from the liquid solution and cooling the same.
23. A culture unit as claimed in claim 22, comprising:
- means for transferring said liquid solution to the photobioreactor.
- means for transferring said liquid solution to the photobioreactor.
24. A culture unit as claimed in claim 23, wherein the photobioreactor is as defined in claim 1.
25. A process for producing photosynthetic organisms, the process comprising the steps of:
a) cultivating a photosynthetic organism in a photobioreactor as defined in claim 1, and thereby obtaining a liquid culture medium containing photosynthetic organisms;
b) removing from said photobioreactor a portion of said liquid culture medium; and c) separating the liquid culture medium of step b) into a solid phase containing the photosynthetic organisms and a liquid phase.
a) cultivating a photosynthetic organism in a photobioreactor as defined in claim 1, and thereby obtaining a liquid culture medium containing photosynthetic organisms;
b) removing from said photobioreactor a portion of said liquid culture medium; and c) separating the liquid culture medium of step b) into a solid phase containing the photosynthetic organisms and a liquid phase.
26. A process as claimed in claim 25, further comprising the steps of):
- producing a solution of bicarbonate ions and hydrogen ions in a bioreactor comprising a reaction chamber containing immobilized carbonic anhydrase or analog thereof capable of catalyzing the hydration of dissolved CO2 into bicarbonates ions and hydrogen ions; and - feeding the photobioreactor with the solution of bicarbonates ions and hydrogen ions produced in the bioreactor.
- producing a solution of bicarbonate ions and hydrogen ions in a bioreactor comprising a reaction chamber containing immobilized carbonic anhydrase or analog thereof capable of catalyzing the hydration of dissolved CO2 into bicarbonates ions and hydrogen ions; and - feeding the photobioreactor with the solution of bicarbonates ions and hydrogen ions produced in the bioreactor.
27. A process as claimed in claim 26, comprising the step of:
- feeding the bioreactor with the liquid phase obtained in step c).
- feeding the bioreactor with the liquid phase obtained in step c).
28. A process as claimed in claim 27, wherein step c) of separating comprises a process selected from the group consisting of filtration, flocculation, sedimentation and centrifugation.
29. A process as claimed in claim 28, comprising, prior to the step of feeding the photobioreactor the step of:
- adding to said solution of bicarbonates ions and hydrogen ions a concentrate liquid culture medium, and thereby forming a liquid solution.
- adding to said solution of bicarbonates ions and hydrogen ions a concentrate liquid culture medium, and thereby forming a liquid solution.
30. A process as claimed in claim 29, comprising the step of feeding said liquid solution into a heat exchanger for recovering heat from the liquid solution and cooling the same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2393188 CA2393188A1 (en) | 2001-10-17 | 2002-07-12 | Photobioreactor |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2,359,417 | 2001-10-17 | ||
| CA002359417A CA2359417A1 (en) | 2001-10-17 | 2001-10-17 | Photobioreactor with internal artificial lighting |
| CA 2393188 CA2393188A1 (en) | 2001-10-17 | 2002-07-12 | Photobioreactor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2393188A1 true CA2393188A1 (en) | 2003-04-17 |
Family
ID=25682758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2393188 Abandoned CA2393188A1 (en) | 2001-10-17 | 2002-07-12 | Photobioreactor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2393188A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014018338A1 (en) * | 2012-07-23 | 2014-01-30 | Georgia Tech Research Corporation | Nitrate and carbonate concentration for high glucose content in microalgae |
| CN110240998A (en) * | 2018-03-07 | 2019-09-17 | 曾坚 | The closed bioreactor of the shell and tube of automatic cleaning tube wall |
| CN113073049A (en) * | 2021-04-21 | 2021-07-06 | 河南亚都实业有限公司 | Bioreactor for artificial skin tissue culture |
| WO2023174444A1 (en) * | 2022-03-16 | 2023-09-21 | 德默特生物科技(珠海)有限公司 | Hybrid photobioreactor |
-
2002
- 2002-07-12 CA CA 2393188 patent/CA2393188A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014018338A1 (en) * | 2012-07-23 | 2014-01-30 | Georgia Tech Research Corporation | Nitrate and carbonate concentration for high glucose content in microalgae |
| CN110240998A (en) * | 2018-03-07 | 2019-09-17 | 曾坚 | The closed bioreactor of the shell and tube of automatic cleaning tube wall |
| CN113073049A (en) * | 2021-04-21 | 2021-07-06 | 河南亚都实业有限公司 | Bioreactor for artificial skin tissue culture |
| WO2023174444A1 (en) * | 2022-03-16 | 2023-09-21 | 德默特生物科技(珠海)有限公司 | Hybrid photobioreactor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6602703B2 (en) | Photobioreactor | |
| Tredici | Mass production of microalgae: photobioreactors | |
| Pulz et al. | Photobioreactors: design and performance with respect to light energy input | |
| CN102203233B (en) | Algae growth system | |
| US20190185796A1 (en) | Light Emitting Diode Photobioreactors And Methods Of Use | |
| US20110070632A1 (en) | Photo bioreactor and cultivation system for improved productivity of photoautotrophic cell cultures | |
| Nwoba et al. | Pilot-scale self-cooling microalgal closed photobioreactor for biomass production and electricity generation | |
| Miyamoto et al. | Vertical tubular reactor for microalgae cultivation | |
| US20140315291A1 (en) | Solar Conversion System And Methods | |
| MX2008010770A (en) | Photobioreactor and uses therefor. | |
| AU2004256839A1 (en) | Multi-layered photobioreactor and method of culturing photosynthetic microorganisms using the same | |
| JP2010530757A (en) | Bioreactor | |
| WO2010138571A1 (en) | Photobioreactor and method for culturing and harvesting microorganisms | |
| KR20090038313A (en) | High efficiency photo-bioreactor for culturing micro algae | |
| WO2008151376A1 (en) | Apparatus and method for the culture of photosynthetic microorganisms | |
| WO2013082713A1 (en) | Low-cost photobioreactor | |
| AU2009261523A1 (en) | Photobioreactor, system and method for the cultivation of photosynthetic microorganisms | |
| CA2760336A1 (en) | Method of culturing photosynthetic organisms | |
| US20210002595A1 (en) | Culture tank | |
| WO2012077081A1 (en) | A fluid agitator device for facilitating development of algae or micro-algae in trays or photobioreactors | |
| Pozza et al. | A novel photobioreactor with internal illumination using Plexiglas rods to spread the light and LED as a source of light for wastewater treatment using microalgae | |
| Sergejevová et al. | Photobioreactors with internal illumination | |
| CA2393188A1 (en) | Photobioreactor | |
| KR101372328B1 (en) | Vinyl sheet type photobioreactor and method for manufacturing the same | |
| AU736564B2 (en) | Culture of micro-organisms |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |