PHOTOBIOREACTORS AND METHODS

FOR UPSCALE PRODUCTION OF BIOMASSES

FIELD OF THE INVENTION The invention described herein relates to photobioreactors, systems comprising same and methods for operating same,

BACKGROUND

A bioreactor is a device for the production of microorganisms outside their natural environment. The photobioreactor facilitates cultivating phototrophic microorganisms, or organisms, which grow by utilizing light energy. These organisms use the process of photosynthesis to build their own biomass from light and CO2. Key objectives of photobioreactors are to provide controlled supply of specific environmental conditions required for the culture of the particular species. Generally, photobioreactors can be divided into open and closed systems. In the open systems, the biomass is cultured in ponds, which contain necessary nutrients and CO2, and which are being directly illuminated from sunlight via their liquid surface. Albeit being relatively cheap, the open systems require large amounts of land area and have temperature and light fluctuations due to seasonal variations. Another problem with open bioreactors is exposure to foreign microorganism contaminants that usually compete with the target cultured strain, diminishing or neutralizing the growth rate of the organism of interest.

In the closed systems, the biomass is cultured in vessels (tubes, boxes, serpentines, etc.), which require less land for the same biomass production. Light and heat are provided by various methods inside the system. The closed systems generally allow more precise control over growth parameters and provide an isolated environment with a much lower probability of contamination by other algal strains or microorganisms. However, although quite efficient in laboratory scale, there is little or no development in techniques to scale them up to industrial size. SUMMARY

The present disclosure relates to photobioreactors, conditioning units configured to control the operation of photobioreactors and systems including same. Specifically the disclosure relates to photobioreactors and systems suitable for large- scale production of biomass.

The photobioreactors of the present disclosure may, for example, be used to produce biomass, such as, but not limited to, algae.

One of the most important design and performance parameters for a bioreactor is the amount of CO2 captured, or converted into biomass, through the photosynthetic process. One type of photobioreactor addressing this challenge is the airlift reactor. These reactors, which are usually composed of an internal tube or baffle that induces a liquid flow pattern, are frequently used as bioreactors on a research scale for growing microalgae.

However, attempts to utilize the airlift principle in large-scale reactors have failed. This is largely due to insufficient mixing (and hence CO2 supply) and lack of adequate illumination. Using pneumatic mixing by injecting a gas, as a means of circulation in a large-diameter reactor, is thought to be inefficient since areas of the reactor are left stagnant, thereby resulting in lower net productivity. Likewise, during the cultivation process, the density of the biomass increases and, upon exceeding a certain critical size, rapidly leads to extinction of the light flux in major portions of the reactor.

The photobioreactors of the present disclosure include a plurality of reactor compartments each based on the airlift principle. Each compartment may, on the one hand, function as a separate reactor unit and thereby retain the advantages of small- scale reactors, such as, but not limited to, efficient mixing and illumination of the biomass. On the other hand, the growth in all reactor compartments is effectively controlled by a special controller unit which ensures high reproducibility in all compartments as well as significant reduction in the costs involved with controlling a plurality of independently controlled photobioreactors. Hence, the photobioreactors, disclosed herein, enable to achieve higher productivity at lower costs as compared to known photobioreactors in general, and to large-scale photobioreactors in particular.

According to some embodiments, there is provided a photobioreactor system comprising: at least one photobioreactor comprising a plurality of reactor compartments; and a conditioning unit configured to control the operation of said at least one photobioreactor; wherein controlling the operation of said at least one photobioreactor comprises coordinating growth in said plurality of reactor compartments and identifying a transition point in a bioprocess taking place in said photobioreactor.

According to some embodiments, detecting the transition point comprises determining a nitrate concentration in a growth culture in at least one of the plurality of reactor compartments. According to some embodiments, determining the nitrate concentration comprises determining a color of the growth culture. According to some embodiments, controlling the operation of the at least one photobioreactor comprises disconnecting a reactor compartment from the at least one photobioreactor if contamination is detected therein.

According to some embodiments, the plurality of reactor compartments comprises at least 10 compartments. According to some embodiments, the plurality of reactor compartments comprises at least 100 compartments.

According to some embodiments, each of the plurality of reactor compartments is an air-lift photobioreactor unit comprising an outer tube and an inner tube.

According to some embodiments, the plurality of compartments comprises a gas sparger configured to inject a gas into the riser tube. According to some embodiments, the gas sparger is located inside the riser tube.

According to some embodiments, each of the plurality of compartments comprises at least one light source. According to some embodiments, the at least one light source is located outside each of the plurality of reactor compartments. According to some embodiments, the conditioning unit is configured to refine the operation of the photobioreactor, if one or more reactor compartments have been disconnected.

According to some embodiments, the system also comprises at least one sensor configured to provide at least one signal indicative of the transition point. According to some embodiments, the at least one sensor is a digital camera. According to some embodiments, the conditioning unit comprises a communication unit configured to receive the at least one signal from the at least one sensor.

According to some embodiments, the conditioning unit comprises a processor configured to analyze the at least one signal and to control an operation of the at least one photobioreactor in response to the at least one signal.

According to some embodiments, the conditioning unit is configured to induce a change in the operation of said photobioreactor based on the detected transition point. According to some embodiments, inducing a change in the operation of the photobioreactor comprises intensifying irradiation on each of the plurality of reactor.

According to some embodiments, the conditioning unit is configured to control a flow of gas to said photobioreactor. According to some embodiments, the conditioning unit is further configured to create an inoculum. According to some embodiments, the conditioning unit is further configured to produce a broth used as growth media. According to some embodiments, the conditioning unit is further configured to drain the at least one photobioreactor and to harvest a biomass. According to some embodiments, the conditioning unit is further configured to process the biomass.

According to some embodiments, the conditioning unit is further configured to produce a heated steam, ozone or other sterilizing gas. Additionally or alternatively, the conditioning unit is configured to produce a mixture of sterilizing chemicals. According to some embodiments, the conditioning unit is further configured to sterilize the at least one photobioreactor. According to some embodiments, the conditioning unit comprises a communication unit configured to communicate with the at least one photobioreactor and/or said plurality of reactor compartments. According to some embodiments, the system further comprises an isolating container, configured to maintain a stable desired temperature therein, wherein the photobioreactor and/or the conditioning unit is configured to be placed within the isolating container.

According to some embodiments, said system, or one or more parts thereof, are mobile. According to some embodiments, the system, or one or more parts thereof, are stackable.

According to some embodiments, the system is for the use of growing algae. According to some embodiments, the algae is Haematococcus pluvialis.

According to some embodiments, there is provided a photobioreactor comprising a plurality of reactor compartments, each of the plurality of reactor compartments comprising: an outer tube and an inner tube, wherein the outer tube is a down comer tube and the inner tube is a riser tube; a gas sparger configured to inject a gas into the riser tube; and at least one light source; wherein each of the plurality of reactor compartments is a separate air-lift photobioreactor unit, and wherein each of the plurality of reactor compartments is configured to be disconnected from the photobioreactor if contamination is detected therein.

According to some embodiments, the plurality of reactor compartments comprises at least 10 compartments. According to some embodiments, the plurality of reactor compartments comprises at least 100 compartments. According to some embodiments, said at least one light source is located outside each of the plurality of reactor compartments.

According to some embodiments, there is provided a conditioning unit configured to control operation of at least one photobioreactor comprising a plurality of reactor compartments; wherein controlling the operation of the at least one photobioreactor comprises coordinating growth in the plurality of reactor compartments and identifying a transition point in a bioprocess taking place in the photobioreactor.

According to some embodiments, controlling the operation of the at least one photobioreactor further comprises to disconnect a reactor compartment from the at least one photobioreactor if contamination is detected therein.

According to some embodiments, the conditioning unit is further configured to induce a change in the operation of the photobioreactor based on the detected transition point. According to some embodiments, inducing a change in the operation of the photobioreactor comprises intensifying irradiation on each of the plurality of reactor compartments .

According to some embodiments, the conditioning unit is configured to control the flow of gas to the photobioreactor. According to some embodiments, the conditioning unit is configured to create an inoculum. According to some embodiments, the conditioning unit is configured to produce a broth used as growth media. According to some embodiments, the conditioning unit comprises a communication unit configured to communicate with the at least one photobioreactor and/or the plurality of reactor compartments.

According to some embodiments, the communication unit is configured to receive at least one signal from at least one sensor, the at least one signal indicative of the transition point.

According to some embodiments, the conditioning unit is configured to analyze the at least one signal and to control an operation of the at least one photobioreactor in response to the at least one signal.

According to some embodiments, the conditioning unit is configured to produce a heated steam, ozone or other sterilizing gas/gasses. Additionally or alternatively, the conditioning unit is configured to produce a mixture of chemicals used to sterilize the at least one photobioreactor.

According to some embodiments, there is provided a method for upscale culturing biomasses, comprising providing a photobioreactor system according to any of the embodiments described herein; culturing in the photobioreactor system algae; harvesting the algae culture; and extracting from the algae a bioproduct.

According to some embodiments, the bioproduct is a carotenoid. According to some embodiments, the bioproduct is astaxanthin.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples illustrative of embodiments are described below with reference to figures attached hereto. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same numeral in all the figures in which they appear. Alternatively, elements or parts that appear in more than one figure may be labeled with different numerals in the different figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown in scale. The figures are listed below. FIG. 1 schematically illustrates a photobioreactor, according to some embodiments.

FIG. 2 schematically illustrates a reactor compartment, according to some embodiments.

FIG. 3 schematically illustrates a container, according to some embodiments. FIG. 4 schematically illustrates a photobioreactor system comprising a photobioreactor and a conditioning unit, according to some embodiments.

FIG. 5 schematically illustrates a block diagram of the operation of a photobioreactor system, according to some embodiments;

FIG. 6 schematically illustrates a block diagram of the operation of a photobioreactor system, according to some embodiments;

FIG. 7 schematically illustrates a block diagram of the operation of a photobioreactor system, according to some embodiments. DETAILED DESCRIPTION

In the following description, various aspects of the disclosure will be described. For the purpose of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the different aspects of the disclosure. However, it will also be apparent to one skilled in the art that the disclosure may be practiced without specific details being presented herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the disclosure.

There is provided, according to some embodiments, a photobioreactor comprising a plurality of reactor compartments. As used herein the term "photobioreactor" may refer to devices intended to grow photosynthetic organisms, such as, but not limited to, algae, by providing an optimized environment and the necessary resources.

As used herein the terms "reactor compartment" and "reactor cell" may interchangeably refer to chambers or subunits, each functioning as a standalone photobioreactor, each having its own growth culture. It is understood by one of ordinary skill in the art that the reactor compartments may be placed horizontally or vertically inside the photobioreactor and may have any suitable shape, such as, but not limited to, hoses, tubes, plates, bags or any other appropriate shape.

According to some embodiments, each of the plurality of reactor compartments is configured to be disconnected from the photobioreactor, if contamination is detected. Hence, if contamination is detected in one of the plurality of reactor compartments, the contaminated compartment may be disconnected from the photobioreactor such that growth can proceed in the remaining reactor compartments without further contamination. According to some embodiments, the disconnect on can be a functional disconnection meaning that the contaminated compartment will receive no more supplies (such as growth media, CO2 and/or light), growth in the contaminated compartment will be halted and/or no biomass will be collected from the compartment. Additionally or alternatively, the disconnection can be physical meaning that the contaminated compartment is physically detached from the photobioreactor, for example to undergo enhanced cleaning.

As used herein the terms "at least one" and "one or more" may interchangeably refer to 1, 2, 3, 4, 5, 10, 100 or more, any number or range there between or any other suitable number. Each possibility is a separate embodiment. As a non-limiting example, at least one photobioreactor may refer to 10 or more photobioreactors. As a non-limiting example, at least one reactor compartment may refer to 10 or more reactor compartments, such as 36 reactor compartments. As another non-limiting example, the at least one reactor compartment may refer to 100 or more reactor compartments, such as 216 reactor compartments.

As used herein the term "about" refers to +/-10%.

According to some embodiments, each of the plurality of reactor compartments is a separate air-lift photobioreactor. As used herein the term "air-lift photobioreactor" may refer to reactors composed of an inner tube (riser tube) and an outer tuber (downcomer tube). In the airlift photobioreactor, mixing is achieved by injecting air into the riser compartment, which then allows fluid circulation through the downcomer compartment. Due to this pneumatic mixing, the air-lift photobioreactor does not necessitate using a pump and therefore avoids the cell damage associated with mechanical pumping. It is understood to one of ordinary skill in the art that this may be of particular importance when growing biomass sensitive to shear stress, such as, but not limited to, Haematococcus pluvialis. Nonetheless, according to some embodiments, the photobioreactor may also comprise a pump as an additional means of mixing.

According to some embodiments, each of the plurality of reactor compartments comprises a gas sparger configured to inject the gas into the riser tube. According to some embodiments, the sparger is located outside the riser tube. According to some embodiments, the sparger is located inside the riser tube. According to some embodiments, the sparger injects the gas such that the flow in the downcomer tube is laminar and flow in the riser tube turbulent, thereby enabling efficient circulation throughout the entire reactor compartment.

The liquid velocity is determined by the gas flow in the reactor. Controlling the flow of gas is of uttermost importance. Flow rates too high may induce excessive levels of turbulence inside the reactor, which is both a potentially dangerous shearing condition, for example, for microalgae cells, and may also generate bubbles, which reduce light distribution. Flow rates too low, on the other hand, may decrease the circulation velocity in the reactor and thereby create stagnant zones in the system. Efficient control of pneumatic mixing using a sparger is possible only, when each of the plurality of compartments retains a suitable size, as further elaborated herein below. According to some embodiments, controlling the flow of gas reduces wastage of the gas and consequently the expenses involved in operating the photobioreactor. It is understood by one of ordinary skill in the art that wastage of gas may have a tremendous influence on cost of production since nutrition grade products requires use of clean gasses.

According to some embodiments, each of the plurality of reactor compartments further comprises at least one light source. As used herein the term "at least one" with regards to light sources may refer to 1, 2, 3, 4, 5, 6, 10, or more light sources, as well as any number or range there between. Each possibility is a separate embodiment.

According to some embodiments, the at least one light source is located outside each of the plurality of reactor compartments. Alternatively, the at least one light source is located outside a stack of reactor compartments. As used herein, the term "stack" with regards to reactor compartments may refer to 2, 3, 4, 5, 6, 10, 20, 30, 36 or more reactor compartments, as well as any number or range there between. Each possibility is a separate embodiment. The stacks may be arranged, such that the compartments are piled together in groups.

According to some embodiments, the at least one light source is located inside each of said plurality of reactor compartments. According to some embodiments, the at least one light source is located inside and outside each of said plurality of reactor compartments.

According to some embodiments, the at least one light source may include a light-emitting diode (LED). Additionally or alternatively, the at least one light source may include an incandescent light source and/or a fluorescent lamp. It is understood that the photobioreactor disclosed herein, comprising the plurality of reactor compartments, enables to reduce the amount of light energy required to efficiently irradiate the entire biomass grown in each of the reactor compartments. The photobioreactor, disclosed herein, thus enables to achieve large biomasses (as further elaborated below) while using minimal energy, thereby making the photobioreactor of the present disclosure both cost effective and environmentally friendly. Furthermore, the photobioreactor, disclosed herein, also enables to maintain optimal irradiation of the biomass independently of climate conditions and/or weather changes. According to some embodiments, the working volume of each of the plurality of reactor compartments is in the range of 30-150dm ³ , 50-120dm ³ or 75-100dm ³ . Each possibility is a separate embodiment.

According to some embodiments, each of said plurality of reactor compartments comprises a growth culture. As used herein the term "growth culture" refers to a medium broth in which a living organism (such as, but not limited to, a microalgae) is grown.

According to some embodiments, the photobioreactor is for producing biomass. As used herein the term "biomass" refers to any biological material derived from living, or recently living organisms. According to some embodiments, the biomass is selected from the group consisting of plants, mosses, macroalgae, microalgae, cyanobacteria, purple bacteria or combinations thereof. According to some embodiments, the biomass is algae. According to some embodiments, the microalgae are selected from the group consisting of: Haematococcus pluvialis, Chlorella vulgaris, Arthrospira platensis, Dunaliella salina. Each possibility is a separate embodiment. According to some embodiments, the biomass is Haematococcus pluvialis known for its high content of the strong antioxidant astaxanthin. Haematococcus pluvialis is characterized as having two growth phases, a green phase and a red phase. When subjected to favorable conditions, Haematococcus pluvialis grows as motile, green cells that reproduce primarily by cell division (green phase). The high amount of astaxanthin is present in the resting cells (red phase), which are produced and rapidly accumulated when the environmental conditions become unfavorable for normal cell growth.

According to some embodiments, the final bioproduct extracted from the algae is an antioxidant. According to some embodiments, the final bioproduct extracted from the algae is astaxanthin.

According to some embodiments, the monthly production of dry biomass by the photobioreactor is in the range of 100-400kg, 150-300kg or 200-250kg. Each possibility is a separate embodiment. According to some embodiments, the monthly production of astaxanthin by the photobioreactor is in the range of l-20kg, 2- 15kg or 5- 10kg. Each possibility is a separate embodiment.

According to some embodiments, the photobioreactor may further comprise one or more sensors configured to monitor at least one signal indicative of the growth in the at least one photobioreactor. According to some embodiments, the at least one signal is indicative of a transition point in the bioprocess in the at least one bioreactor.

As used herein, the term "transition point" may refer to a switch in the growth phase and/or the bioprocess of the biomass, for example a point at which the production of a bioproduct is or may be commenced. For example, according to some embodiments, the transition point refers to a change from green phase to red phase in the growth phase of Haematococcus pluvialis. According to some embodiments, the green phase is characterized as having high nitrate concentrations and the red phase by low concentrations of nitrate or even absence of nitrate. As used herein, the term "bioprocess" may refer to any process that uses complete living cells or their components (e.g., algae) to obtain a desired bioproduct (e.g. astaxanthin).

According to some embodiments, the at least one sensor is configured to monitor vital algae growth parameters, such as, but not limited to, pH, nutrients levels, light intensity, light cycle, ultraviolet exposure, 0 ₂ concentrations, CO2 concentrations, nitrate concentration, growth solution color and combinations thereof. According to some embodiments, the at least one sensor comprises 1, 2, 3, 4 or more sensors. Each possibility is a separate embodiment.

As used herein, the term "sensor" may refer to any device configured to monitor vital algae growth parameters. According to some embodiments, the sensor comprises a digital camera configured to take fixed white-balance pictures of the growth solution from which a color histogram can be derived. According to some embodiments, the sensor comprises a color sensor, such as, but not limited to, a color sensor.

According to some embodiments, each of the plurality of reactor compartments further comprises a gas exchanger configured to remove the oxygen produced during photosynthesis.

There is provided, according to some embodiments, a conditioning unit configured to control operation of at least one photobioreactor, such as, for example, but not limited to, 10 photobioreactors. According to some embodiments, controlling the operation of said at least one photobioreactor comprises coordinating growth in said plurality of reactor compartments and, if contamination is detected in one or more of the plurality of reactor compartments, disconnecting said one or more contaminated reactor compartment from the at least one photo-hioreactor.

Efficient growth in a photobioreactor composed of multiple reactor compartments requires that the growth in all of the single reactor compartments is carefully coordinated. According to some embodiments, coordinating the growth comprises keeping at least one vital algae growth parameter within a desired, optionally, stable, range in each of the single compartments. According to some embodiments the at least one vital algae growth parameter is selected from the group consisting of: pH, oxidation reduction potential (ORP), conductivity, nutrients level, light intensity, light cycle, ultraviolet exposure, 0 ₂ concentrations, CO2 concentrations, nitrate concentration, color of growth solution and combinations thereof. Each possibility is a separate embodiment.

According to some embodiments, a reduction in nitrate concentration in the growth solution is indicative of a transition point in the growth culture. According to some embodiments, the nitrate concentration in the growth solution affects the color of the growth solution. According to some embodiments, the color of the growth solution may be determined by decoding color histograms of pictures taken by a digital camera or a color sensor having fixed white balance. As used herein the term "color histogram" may refer to the number of pixels in the picture that have colors in each of a fixed list of color ranges in an RGB color space. According to some embodiments, the color maybe determined using a spectrophotometer.

According to some embodiments, contamination of the growth solution may also affect the color of the growth solution. Thus, the RGB color histogram may serve as a 'fingerprint' of the growth solution, which may be utilized to determine the status of the growth solution.

It is further understood by one of ordinary skill in the art that the at least one vital algae growth parameter may be 1 , 2, 3 or more parameters. Each possibility is a separate embodiment.

According to some embodiments, the conditioning unit comprises a communication unit configured to communicate with the at least one photobioreactor and/or with the plurality of reactor compartments. According to some embodiments, the communication unit may be physically connected to the at least one photobioreactor and/or to the plurality of reactor compartments, for example, through landlines, such as cables, lubes or other suitable means of interconnection. It is understood by one of ordinary skill in the art that the physical connection may be utilized to transfer, for example, supplies, samples and the like from the conditioning unit to the at least one photobioreactor and/or to the plurality of reactor compartments and vice versa. Additionally or alternatively the communication unit may be configured to communicate with the at least one photobioreactor and/or with the plurality of reactor compartments through wireless connections for signal transfer, such as, but not limited to, Wi-Fi, Bluetooth or other suitable means of signal transfer, in some embodiment, the plurality of reactor compartments is indirectly connected such that the connection is via the conditioning unit.

According to some embodiments, the communication unit is configured to receive at least one signal from one or more sensors, for example, by means of wireless signal transfer. According to some embodiments, the at least one sensor may be configured to monitor at least one vital algae growth parameter. According to some embodiments, the conditioning unit further comprises a processor configured to analyze the at least one signal. According to some embodiments, analyzing the at least one signal compri ses determining whether the parameter is within a required range.

According to some embodiments, the conditioning unit may further adjust the operation of the photobioreactor and/or of reactor compartments, if the parameter is determined to be out of range.

According to some embodiments, the conditioning unit may be configured to detect a transition point in the growth culture based on the at least one vital algae growth parameter. According to some embodiments, the conditioning unit may be further configured to adjust and/or induce a change in the operation of the photobioreactor based on the detected transition point. For example, the conditioning unit may be configured to detect a transition point at which the growth phase of Haematococcus pluvialis has been completed. At that point, red phase - during which astaxanthin is generated - may be induced (e.g. by enhancing the irradiation of the culture with LED). According to some embodiments, the transition point is detected by detecting a nitrate concentration in the growth solution. According to some embodiments, the conditioning unit is configured to detect the nitrate concentration of the growth solution by determining the color of the growth solution. The color of the growth solution may be determined by analyzing a color histogram of a fixed white-balance digital picture of the growth solution.

According to some embodiments, adjusting and/or changing the at least one vital algae growth parameter may comprise modifying pH in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, supplying nutrients to at least one of the at least one photobioreactor and/or to at least one of the plurality of reactor compartments, modifying a light intensity in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, modifying a light cycle in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, changing ultraviolet exposure in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, adjusting 0 ₂ concentrations in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, adjusting CO2 concentrations in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments. Each possibility is a separate embodiment.

Additionally or alternatively, if the signal indicates that one or more reactor compartments are contaminated, the conditioning unit may disconnect the contaminated compartrnent(s) to avoid further contamination. According to some embodiments, if the signal indicates that one or more reactor compartments are contaminated, the conditioning unit disconnects itself from said one or more reactor compartments. According to some embodiments, the conditioning unit is further configured to refine the operation of the photobioreactor based on the reduced amount of active reactor compartments. For example, the conditioning unit may be configured to turn off the light sources configured to illuminate the disconnected reactor compartments. For example, the conditioning unit may stop supply of growth media to the disconnected reactor compartments. Such modularity of the photobioreactor may significantly reduce costs and unnecessary wastage.

According to some embodiments, refining the operation of the photobioreactor comprises modifying pH in at least one of the a least one photobioreactor and/or in at least one of the plurality of reactor compartments, supplying nutrients to at least one of the at least one photobioreactor and/or to at least one of the plurality of reactor compartments, modifying a light intensity in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, modifying a light cycle in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, changing ultraviolet exposure in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, adjusting 0 ₂ concentrations in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments, adjusting CO2 concentrations in at least one of the at least one photobioreactor and/or in at least one of the plurality of reactor compartments. Each possibility is a separate embodiment.

The at least one vital algae growth parameter may be out of range in each of the plurality of compartments, in a single reactor compartment or in a group of reactor compartments. Correspondingly, the conditioning unit may be configured to adjust the at least one vital algae growth parameter in the entire photobioreactor, in the single reactor compartment or in the group of reactor compartments. As used herein the term "group" with regards to reactor compartments may refer to 2, 3, 4, 5, 6, 10, 20, 30, 36 or more reactor compartments or any number there between. According to some embodiments, the entire process is fully automated.

According to some embodiments, the conditioning unit is further configured to receive CO2 from a CO2 source. Additionally or alternatively, the conditioning unit may further be configured to receive a flue gas, for example, from chimneys of power plants, to clean the flue gas by removing heavy metals, such as, but not limited to, SO2, NO _x , and/or particles thereof, and to generate a mixture from the cleaned flue gas and compressed air.

According to some embodiments, the conditioning unit may further be configured to supply gas to the photobioreactor. According to some embodiments, the conditioning unit may further be configured to control the flow of gas in the plurality of reactor compartments. According to some embodiments, controlling the flow of gas in the plurality of reactor compartments comprises controlling the operation of gas spargers in the plurality of reactor compartments. According to some embodiments, controlling the flow of gas reduces the waste of the gas and consequently reduces the expenses involved in operating the photobioreactor.

According to some embodiments, the conditioning unit may further be configured to generate and/or supply an inoculum to the photobioreactor. According to some embodiments, the conditioning unit may further be configured to produce and/or supply a broth used as growth media to the photobioreactor. According to some embodiments generating and/or supplying an inoculum, as well as producing and/or supplying a broth, may be fully automated processes. According to some embodiments, the conditioning unit is further configured to drain and/or initiate draining of the at least one photobioreactor such that the biomass can be harvested. According to some embodiments, the conditioning unit is further configured to process the biomass by drying and/or cracking the cell walls of the biomass. Additionally or alternatively, the conditioning unit is configured to initiate drying and/or cracking the wails of the biomass. According to some embodiments, the conditioning unit comprises one or more chambers configured to contain the harvested and/or processed biomass.

According to some embodiments, the conditioning unit is further configured to produce a heated steam, ozone or a chemical mixture used to sterilize said at least one photobioreactor. According to some embodiments, the heated steam has a temperature of at least 100°C, of at least 110°C or of at least 130°C. Each possibility is a separate embodiment. According to some embodiments, all processes performed or initiated by the conditioning unit are fully automated.

There is provided, according to some embodiments, a photobioreactor system comprising: at least one photobioreactor comprising a plurality of reactor compartments; and a conditioning unit configured to control the operation of the photobioreactor, as essentially described above. According to some embodiments, controlling the operation of the photobioreactor comprises coordinating growth in the plurality of reactor compartments and, if contamination is detected in one or more of the reactor compartments, to disconnect the contaminated reactor compartment from the photobioreactor, as essentially described above.

According to some embodiments, the system further comprises one or more sensors configured to monitor at least one signal indicative of the growth in said at least one photobioreactor. According to some embodiments, the at least one sensor is configured to monitor vital algae growth parameters, such as, but not limited to, pH, oxidation reduction potential (ORP), nutrients, light intensity, light cycle, ultraviolet exposure, 0 ₂ concentrations, CO2 concentrations and combinations thereof. According to some embodiments, the at least one sensor comprises 1, 2, 3, 4 or more sensors. Each possibility is a separate embodiment.

According to some embodiments, the at least one sensor is configured to transfer the monitored parameters as signals to the conditioning unit. The conditioning unit then analyzes and, if needed, adjusts the at least one signal or disconnects contaminated reactor compartments, as essentially described above.

According to some embodiments, the system further comprises a container. According to some embodiments, the container is an isolating container configured to maintain a stable and controllable temperature therein. According to some embodiments, the container is an ISO 1AAA container or other closed and/or insulated room/container.

According to some embodiments, the photobioreactor is sized and shaped to be placed inside the isolating container, such that the desired temperature inside each of the plurality of reactor compartments is maintained stable. According to some embodiments, the conditioning unit is sized and shaped to be placed inside the isolating container in order to maintain a desired temperature therein. The isolating container enables to obtain and maintain optimal growth conditions irrespectively of climate and/or weather changes. According to some embodiments, the system, or one or more parts thereof, are mobile. According to some embodiments, the system, or one or more parts thereof, are stackable. As used herein the term "part of, with regards to the system, may refer to photobioreactor(s), subunits of the photobioreactor(s), such as one or more reactor compartment, the conditioning unit, subunits of the conditioning unit, such as, for example, containers configured to contain the harvested and/or processed biomass.

According to some embodiments, the system or parts thereof can easily be transported, for example, from one location to another.

According to some embodiments, the entire operation of the photobioreactor svstem mav be ftillv automated. There is provided, according to some embodiments, a method of photobioreactor operation comprising: growing algae in a plurality of reactor compartments, monitoring vital algae growth parameters, determining whether the vital algae growth parameters are within a desired range and, if the vital algae growth parameters are out of range, to adjust the parameters and/or disconnecting contaminated reactor compartments.

According to some embodiments, the method further comprises receiving and cleaning a flue gas. According to some embodiments, the method may further comprise preparing and supplying an inoculum, According to some embodiments, the method may further comprise producing and/or supplying a broth used as growth media, in the reactor compartments. According to some embodiments, the method may further comprise draining the plurality of reactor compartments to facilitate harvest of the biomass. According to some embodiments, the method may further comprise drying and/or cracking the algae ceil walls. According to some embodiments, the method further comprises producing a heated steam, ozone or chemical mixture utilized to sterilize the reactor compartments. Each possibility is a separate embodiment.

Reference is now made to FIG. 1, which schematically illustrates a photobioreactor 10, according to some embodiments. Photobioreactor 10 include a plurality of reactor compartments, such as reactor compartment 100. According to some embodiments, the reactor compartments may be arranged in stacks, such as stack 150. According to some embodiments, the number of compartments in a stack may be in the range of 10-100 or 10-50. Each possibility is a separate embodiment.

According to some embodiments, the stack may comprise 4, 6, 10, 12, 16, 20, 30, 36, 40, 50 or more reactor compartments, any number therebetween or any other suitable number of compartments. Each possibility is a separate embodiment. The stack may for example contain 36 reactor compartments, as illustrated in FIG 1.

Reference is now made to FIG. 2, which schematically illustrates a reactor compartment 200, according to some embodiments. Reactor compartment 200 may- have an outer downcomer tube, such as downcomer tube 210 and an inner riser tube, such as riser tube 220. According to some embodiments, reactor compartment 200 may also include at least one light source, such as light sources 230 located outside and around photobioreactor 200. Light source 230 is configured to illuminate the biomass grown in the reactor compartment. According to some embodiments, light source 230 comprises a plurality of LEDs, such as LEDs 235. The plurality of LEDs may refer to 2-200, 4-100 LEDs, any number of LEDs within the range or any other suitable range and or number of LEDs. Each possibility is a separate embodiment. Optionally, the at least one light source 230 may be located outside and around a stack of reactor compartments, such as stack 150 of FIG. 1 (option not shown). It is understood by one of ordinary skill in the art that even if light source 230 is located outside and around a stack of reactor compartments, it is configured to efficiently illuminate the biomass grown in each reactor compartment. Reactor compartment 200 may also include a gas sparger, such as gas sparger

240 configured to provide pneumatic mixing of liquids inside the reactor compartment by injecting a gas into riser tube 220. Gas sparger 240 may be located outside riser tube 220. Alternatively, gas sparger 240 may be located inside riser tube 220 (not shown).

Optionally, reactor compartment 200 may also include one or more sensors, for example, in the form of a sensor assembly configured to monitor vital algae growth parameters, such as digital camera 245, configured to monitor the color of the growth solution. Digital camera 245 is here shown to be located inside reactor compartment 200, however, according to some embodiments, digital camera 245 may be located outside reactor compartment 200.

Reference is now made to FIG. 3, which schematically illustrates a container 300, according to some embodiments. Container 300 may be an isolating container, such as, but not limited to, an ISO 1AAA container. Container 300 may have a height H in the range of 2-4 meters, a length L in the range of 5-15 meters and a width W in the range of 1.5-3 meters. Container 300 may be configured to contain therein a photobioreactor, such as photobioreactor 10 of FIG. 1 and/or a conditioning unit, as further elaborated hereinbelow. Container 300 is configured to maintain a stable and controllable temperature therein, such that the desired temperature inside each of the plurality of reactor compartments (and/or in the conditioning unit) is maintained stable. According to some embodiments, container 300 and hence the photobioreactor placed therein, may be mobile and easily transported from one location to another. Reference is now made to FIG. 4, which schematically illustrates a photobioreactor system 400, according to some embodiments. System 400 includes at least one photobioreactor, here illustrated as 4 photobioreactors 410, each comprising a plurality of reactor compartments, as essentially described above. Each of photob oreactors 410 may be situated inside containers, as essentially described above.

System 400 further includes a conditioning unit 450. Conditioning unit 450 is configured to control operation of photobioreactors 410. According to some embodiments, controlling the operation of photobioreactors 410 comprises coordinating the growth in the plurality of reactor compartments of each of photobioreactors 410 and, if contamination is detected in one or more of the reactor compartments, to disconnect the contaminated compartment from its photobioreactor. If reactor compartments are disconnected, conditioning unit 450 may further be configured to refine operaiion of photobioreactor 410, based on the reduced amount of reactor compartment . Conditioning unit 450 generates and/or supplies an inoculum to photobioreactors 410 and produces and/or supplies a broth used as growth media in photobioreactors 410.

Conditioning unit 450 may be configured to receive C0 ₂ or a flue gas from CO2 source 480. If needed, the received flue gas may be filtered, purified or otherwise processed to remove heavy metals, such as, but not limited to, SO2, NO _* and/or particles, and, optionally, mixed with purified CO2, by conditioning unit 450.

Conditioning unit 450 is further configured to detect a transition point in the biomass culture of photobioreactor 410 and to induce a change in the operation of photobioreactor 410 based on the detected transition point, thereby commencing a bio- production phase. For example, conditioning unit 450 may be configured to analyze signals obtained from sensors configured to monitor vital algae growth parameters, such as digital camera (or color sensor) 245 of FIG, 2, configured to monitor the color of the growth culture. Conditioning unit 450 may be configured to receive a color histogram from digital camera 245, and determine whether the color of the growth solution is indicative of a transition point in the growth culture (e.g. a transition to red phase of Haematococcus pluvialis). If the color of the growth solution indicates that the transition point has been reached, conditioning unit 450 may adjust the operation of photo bioreac tors 410, for example, by increasing irradiation of the growth culture by light source 230 of photobioreactor 410. Additionally or alternatively, if the color of the growth soiutioii indicates that one or more reactor compartments are contaminated; conditioning unit 450 may disconnect the contaminated compartment(s) to avoid further contamination.

When the bio -production phase (e.g. red phase of Haematococcus pluvialis) in photobioreactors 410 is completed, conditioning unit 450 may initiate draining of photobioreactors 410 to facilitate harvesting of the biomass, such as the algae. Upon harvest, conditioning unit 450 may initiate processing of the biomass by drying and/or cracking the algae cell walls. The processed biomass may then be transferred to additional units configured to extract astaxanthin therefrom. Advantageously, due to the fact that each of photobioreactors 410 and, optionally, the conditioning unit 450, are mobile, they can easily be transferred to such additional units. Upon completion of growth and harvest of the biomass, conditioning unit 450 may produce a heated steam, ozone or chemical mixture used to sterilize photobioreactors 410 prior to commencing additional growth cycles. Optionally, conditioning unit 450 may be further configured to manage waste produced during the production of the biomass. The components of the system may be mobile by means including, but not limited to, mobile containers) encompassing the system or components thereof.

The entire operation of system 400 may be fully automated.

Reference is now made to FIG. 5, which schematically illustrates a block diagram 500 of the operation of a photobioreactor system, according to some embodiments. Typically, the operation described occurs at the conditioning unit. In step 510, the algae are grown in a plurality of reactor compartments of a photobioreactor, as described herein. At the same time, vital algae growth parameter(s) are monitored using at least one sensor, as described herein. In step 520, the at least one signal is transferred to a communication unit of the conditioning unit, as essentially described above. In step 530, the transferred signal(s) are analyzed by a processor of the conditioning, in order to determine whether the vital algae growth parameters are within a desired range. If the parameters monitored are within the desired range, growth conditions are maintained allowing growth to continue, as in step 540, If the processor identifies parameters out of range, the system proceeds to decision making step 550 for assessing if the parameters can he adjusted as in step 550a. Otherwise, i.e., if contam nation is suspected, then the contaminated reactor compartments) is/are disconnected, as in step 550b. It is understood that the operation illustrated in the diagram can be repeated numerous times during the growth cycle. For example, the growth may proceed unchanged (as in step 540) based on a first signal(s) obtained and then be adjusted (as in step 550a) based on a second signal(s) received at a later stage of the growth cycle. For example, the growth may be adjusted (as in step 550a) based on a first signal(s) obtained and then be left unchanged (as in step 540) based on a second signal(s) received at a later stage of the growth cycle. For example, the growth in a reactor compartment may be adjusted (as in step 550a) based on a first signal(s) obtained and then the compartment may be disconnected (as in step 550b) based on a second signal(s) received at a later stage of the growth cycle.

Reference is now made to FIG. 6, which schematical ly illustrates a block diagram 600 of the operation of a photobioreactor system, according to some embodiments. Typically, the operation described occurs at the conditioning unit. In step 610, the algae are grown in a plurality of reactor compartments of a photobioreactor, as described herein. At the same time, vital algae growth parameter(s) are monitored using at least one sensor, such as, but not limited to, a digital camera (or a color sensor), as described hereinabove, in step 620, the at least one signal, such as but not limited to the color of the growth culture, is transferred to a communication unit of the conditioning unit, as essentially described above. In step 630, the transferred signal(s) are analyzed by a processor of the conditioning unit, in order to detect whether a transition point in the growth culture has been reached. If the transition point has not been reached, growth conditions are maintained to allow continued growth, as in step 640a, If the transition point has been reached, a change in the operation of the photobioreactor and/or of reactor compartments, and thereby in the growth conditions therein, is induced, as in step 640b. For example, irradiation intensity may be increased. It is understood that the operation illustrated in the diagram can be repeated numerous times during the growth cycle. For example, the growth may proceed unchanged (as in step 640a) based on a first signal(s) indicating that the transition point has not been reached and then be changed (as in step 640b) based on a second signal(s) received at a later stage of the growth cycle, indicating that the transition point has been reached.

Reference is now made to FIG. 7, which schematically illustrates a block diagram 700 of the operation of a photobioreactor system as described herein, according to some embodiments. Typically, the operation described is entirely controlled by the conditioning unit and is advantageously fully automated. In step 710, prior to commencing the bioprocess, the photobioreactor is cleaned and waste gathered during the cleaning is optionally managed. At step 715, the conditioning unit sterilizes the photobioreactor, for example, by providing heated steam, ozone or chemical mixture to the plurality of reactor compartments. At step 720, the medium broth is prepared and supplied to the plurality of reactor compartment; and at step 725, a microalgae inoculum is prepared and subsequently added to the medium broth in the plurality of reactor compartments. At step 730, the algae are grown in the plurality of reactor compartments of the photobioreactor. At step 735, the color of the growth culture is determined using a digital camera (or color sensor), as described hereinabove. In step 740, the determined color of the growth culture is communicated to a communication unit of the conditioning unit and, at step 745, a processor of the conditioning unit assesses whether a transition point in the growth culture has been reached, based on the determined color of the growth culture. If the transition point has not been reached, growth conditions are maintained to allow continued growth, as in step 750a, If the transition point has been reached, the light intensity on each the plurality of reactor compartments is intensified, as in step 750b. At step 760, when the bioprocess is completed, the conditioning unit initiates collection and processing of the bioniass, whereupon the bioproduct (e.g. astaxanthin) can be extracted. It is understood, that upon completion, the process can be reinitiated by returning to step 711).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, or components, but do not preclude or rule out the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.

While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, additions and subcombinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced be interpreted to include all such modifications, additions and sub-combinations as are within their true spirit and scope.