MXPA97005284A - Apparatus for the production of biom - Google Patents

Abstract

The present invention resides in a bioreactor for the production of biomass comprising: (i) a substantially transparent chamber, the chamber is at least suitable for containing biomass in a liquid phase, and has a base portion, an upper portion and a number of side walls between the base portion and the upper portion, and (ii) circulation means for circulating the contents of the chamber, wherein the circulation means create an appropriate driving force within the liquid phase to ensure continuous mixing of substantially all the biomass and at least the semi-continuous exposure of the biomass to the source of the

Description

APPARATUS FOR THE PRODUCTION OF BIOMASS This invention relates to an apparatus for the production of biomass and is particularly related to a process for growing biomass using the apparatus. The long-term potential for using autotrophs in the generation, treatment and accumulation of commercial products and waste has become increasingly evident in recent years. Autotrophs are organisms that use C02 as their main source of carbon and obtain energy from the sun through photosynthesis (photoautotrophs) or reduced organic or inorganic chemicals (chemoautotrophs). Typical examples of which include plants, algae, algae cultures, and the like (eg, Chlorella, Spirolina, Dunaliella, etc.), bacteriophages, photosynthetic bacteria and the like. Due to these modest requirements, autotrophic organisms are eminently appropriate for the production of biomass. Algae cultures, for example, have been developed for food for animals and humans, for the treatment of wastewater and waste, for the accumulation of radioactive waste, for the propagation of enzymes and other products that have industrial and research application and for the production of oils and other nutrients that have nutritional value. The traditional procedures used to grow autotrophic organisms have involved the use of open shallow pools or open channels exposed to sunlight. These relatively crude methods for growing autotrophic organisms have proved impractical in that they are subject to contamination by dust, microorganisms, insects, other animals, and environmental contaminants and have limited capacity to control the degree of exposure to light, temperature, respiration, and respiration. other factors. An attempt to overcome these problems has involved the use of a bioreactor system having a comparatively smaller diameter light-accepting tube wound substantially horizontally against the face of a series of flat vertical panels. The problems associated with this form of bioreactor include low density of biomass in the liquid inside the tubes, low penetration of light, coating of the tubes with autotrophic organisms due to the low flow velocity that exists, thereby reducing the transparency, overheating in summer season, high land treatment and manipulation control problems of a sufficiently large number of such units for commercial production. In addition, the design of this reactor gives it an inherently unstable construction unable to withstand adverse weather conditions. An alternative construction has comprised a vertical core structure around which a substantially transparent tube is coiled which allows at least 90% light transmission so that, in use, the outside of the coiled tube is exposed to natural light. To stimulate the penetration of light into the tube, the vertical core structure is adjusted with a light reflecting element. A synthesis mixture comprising material from living plants such as algae, bacteriophages, and marine algae together with essential nutrients for growth is passed through the rolled tube. Again, the coating of the tubes with autotrophic organisms, overheating in summer season, global construction costs, the limited volume of liquid that can pass through the tubes at a time and the difficulty of styling the device between crop runs they have inherent disadvantages for the use of such bioreactors. A somewhat more sophisticated construction has included a bioreactor for the cultivation of photosynthetic microorganisms in which there is a plurality of diverters mounted in a photobioreactor tank where deviators form hollow cavities through the photoreactor which allows the insertion of light sources through of openings in the wall of the tank. Although this construction can maintain a high density of biomass in the liquid culture and reduces the treatment of the land, the complexity of the bioreactor tank, the global construction costs and the overheating in the summer season make this tank not very economical to use on a commercial scale. Also, it is particularly difficult to clean and sterilize between operating cycles. The present invention seeks to provide an improved bioreactor which at least can be manufactured in a variety of different sizes and lengths, and which is suitable for the commercial production of autotrophic organisms. Thus, the present invention resides in a bioreactor for the production of biomass comprising: (i) a substantially transparent chamber, the chamber being at least appropriate for containing biomass in a liquid phase, and having a base portion, a top portion and a number of side walls between the base portion and the upper portion, the side walls are configured to diverge generally from the base portion to the upper portion; and (ii) a circulation means for circulating the contents of the chamber, wherein the circulation means creates an appropriate movement force within the liquid phase to ensure the continuous mixing of substantially all of the biomass and at least the semi-continuous exposure of the biomass. the biomass to a light source. There are a number of parameters that affect the production of biomass within the bioreactor according to the invention. Two of these parameters are the amount of light that enters the chamber and the speed with which the biomass circulates inside the chamber. Preferably, the substantially transparent nature of the camera allows the light to pass. As the density of the biomass in the bioreactor increases, the intensity of penetration of the light in the liquid phase will seem to decrease. Preferably, almost all of the mass is exposed to light at least on a semi-continuous basis. In some cases, the biomass can be subjected to continuous exposure to the light source. This light source can be natural light such as sunlight or can be artificially generated. The flow rate within the chamber should be set at an appropriate level to ensure that continuous mixing of substantially the liquid phase is carried out and thus the biomass is exposed to light during circulation without unduly stressing the biomass. It will be appreciated that some variation in the configuration of the invention can be carried out without departing from the invention. Generally, the circulation system employed in the invention will substantially maintain all of the biomass in continuous suspension and prevent sedimentation of the biomass in the bioreactor. Preferably, all of the biomass is maintained in continuous suspension. The motive force required to generate an appropriate circulation ratio of the liquid phase within the bioreactor will vary depending on the size of the bioreactor, the biomass grown in the bioreactor and the density of that biomass. The minimum circulation ratio of the biomass in the bioreactor is preferably greater than a ratio that would lead to the sedimentation of that biomass. The rate of circulation of the biomass is desirably less than a ratio which could lead to the excessive development of foam on the surface of the liquid phase in the bioreactor and / or which could lead to the biomass being subjected to excessive environmental stress. Preferably the flow rate is established between the minimum flow rate and the maximum flow rate. More preferably, the circulation ratio is established close to the minimum circulation ratio. For example, in a channel-type prism bioreactor or elongate trough with a generally triangular inverted cross-section, circulation can be generated by releasing a gas at or near the inverted apex of the bioreactor. The minimum gas inlet is preferably 12 liters. per meter per minute. The maximum gas inlet is preferably 100 liters. meter per minute. In a highly preferred form of the invention, the entry is 20 liters. per liter per minute. Due to the dynamics of the environment in the bioreactor will continuously undergo changes as the concentration of the mass increases, the circulation ratio is preferably monitored and adjusted so that the circulation ratio never falls below the minimum circulation ratio. It will be appreciated that the present invention can also be used to produce biomass of various types and forms or products derived from biomass. The term "biomass" as used herein includes all organisms capable of photosynthetic growth such as plant cells and microorganisms (algae and euglena) in unicellular or multicellular form that are capable of growing in a liquid phase. The term may also include artificially modified organisms or by genetic manipulation. The bioreactor of the present invention is particularly suitable for cultivation of algae or photosynthetic bacteria. For example, the bioreactor can be used as a photobioreactor for the production of algal biomass. In this aspect, several types of algae (Chlorella, Spirolina, Dunaliella, etc.) can be cultivated in the bioreactor, which have particular and diverse growth requirements. In order for the biomass to breathe, one or more elements need to be supplied in the liquid phase to introduce a gas phase into the liquid phase. This can be carried out by any chemical means that does not kill the biomass or by one or more conduits that open inside the bioreactor. Any gas that is required for photosynthetic activity must be introduced into the bioreactor by this means of delivery. Preferably the gas is air, or carbon dioxide and oxygen. To prevent contamination of the biomass in the reactor the introduced gas is preferably sterilized before being released into the reactor to remove contaminating pathogens in a highly preferred form of the invention, the circulation of the liquid phase is carried out using the gas delivery It will be appreciated that the circulation means may be of various shapes, depending on the configuration of the camera, provided that it at least acts by circulating the contents of the chamber and is capable of providing aeration to the liquid phase maintained within the chamber. camera. Also the circulation medium can be located anywhere within the bioreactor with the condition that it is capable of creating an appropriate motive force within the liquid phase to ensure the continuous mixing of substantially all of the biomass and at least the semi-continuous exposure of the biomass. to a light source. Preferably the circulation means is located adjacent to the base portion or above the upper base portion near the top of the bioreactor. For example, when the circulation medium is located adjacent to the base portion within the bioreactor it desirably generates an upward movement of the biomass and the liquid phase from the base portion to the upper portion of the bioreactor. The upward movement of the liquid phase and biomass impacts the upper surface of the vessel ensuring a brief exposure to the light guaranteed for most of the biomass in the liquid phase. Following contact with the upper surface of the bioreactor, the liquid phase containing the biomass moves outwards towards the sides of the bioreactor. This movement also ensures the exposure of the biomass to the liquid phase to light. The liquid phase containing biomass is then moved down the sides of the bioreactor to the base portion, from where it is again taken up by the circulation medium and driven upwards towards the top of the bioreactor. This mixing regime facilitates the rapid and consistent photosynthetic growth of the biomass, because it ensures the effective exposure of substantially all of the biomass in the liquid phase to the light and also engenders a 'blinking' light pattern that has been shown to improve the development of some photosynthetic organisms. Preferably, the bioreactor has a high ratio of surface area to volume. This can be achieved by employing almost the entire surface of the bioreactor as an active light absorbing / transmitting surface. The absorption and transmission of light can be further improved by employing transparent structural material in the construction of the bioreactor and by suspending the bioreactor slightly above a reflective base surface.

Preferably, the bioreactor is formed as an elongated prism type channel or trough, the prism has a generally triangular inverted cross section. The sides of the generally triangular section are preferably approximately equal and the inverted apex defines the base portion of the chamber. Also the circulation medium is preferably provided inside the chamber at or near the inverted apex, and the sides of the prism define the side walls and the cover elements of the chamber. When the bioreactor is formed as an elongated channel or trough type prism, the longitudinal movement of the liquid phase can be introduced into the circulation by withdrawing the liquid phase from one end of the bioreactor and its subsequent return to the other end as part of a procedure for the administration of biomass. Such movement could also serve to avoid the localized retention of biomass that could occur, which affects in a detrimental way the light exposure regimes of the bioreactor. The transfer of the liquid phase in this manner also allows the perfect mixing and transmission of chemical and physical manipulation of the liquid phase environment of the biomass. The circulation means can be provided as a conduit that extends through the length of the chamber which is located near the base portion of the chamber, the conduit being perforated and connected to a gas source in such a way that in operation the passage of gas out of the duct and into the chamber causes circulation of the contents in the chamber. The passage of gas from the conduit through the liquid phase also provides a means for gas diffusion into the liquid phase, thereby aerating that phase. In this preferred form, the gas is preferably sterile air. In a highly preferred form, the perforations are disposed towards the underlying side of the conduit, the downward passage of the gas helps to prevent the particulate material inside the chamber from settling under the conduit. Thus, in a preferred form the present invention resides in a bioreactor for the production of biomass comprising: (i) a substantially transparent chamber, the chamber being at least suitable for containing biomass in a liquid phase, and having a narrow base portion, an upper portion capable of being sealed by a cover member and a number of side walls diverging from the base portion toward the upper portion; and (ii) a circulation medium for circulating the contents of the chamber, wherein the circulation medium creates an appropriate motive force within the liquid phase to ensure the continuous mixing of the continuous phase and expose the biomass to light, in where the circulation medium is located at or near the lower portion of the base portion and comprises a conduit extending through the length of the bioreactor, the conduit is perforated and connected to a gas source, where the perforations in the conduit are disposed towards the underlying part of the conduit, such that in operation the downward passage of the gas out of the conduit and into the liquid phase (a) prevents the particulate material in the chamber from sedimenting under the conduit , (b) causes the circulation of the liquid phase, and (c) allows the diffusion of gas into the liquid phase. The chamber can be formed as separate pieces of material substantially joined together to form the base portion, the side walls and the cover element, however in a preferred form of the base portion, the side walls and the cover element they are provided as an integral unit, the intersection of the parts, preferably formed as rounded edges. In a highly preferred configuration the bioreactor is specifically designed as an elongated triangular structure, which can accommodate large volumes of liquid phase. The cover element is preferably covered with a slight arc which results in a cover element with a generally convex upper surface. In this form, air vents are preferably provided towards the middle part of the upper convex surface in such a way that the gas is vented from the chamber. The vents may include a filter element, the filter element is at least appropriate to prevent the particulate material from entering the chamber. In addition, the vents can also serve as sampling points to sample biomass within the bioreactor chamber. While the vents can vent directly to the atmosphere they can also be connected to a head, which in turn is connected to an oxygen separation and ventilation system. Thus, expelled gases containing unused carbon dioxide can be collected from these vents and cleaned of their oxygen content before being returned to the bioreactor, in order to facilitate the conservation and efficient use of carbon dioxide. Preferably, the bioreactor also includes a temperature control means for controlling the temperature of the liquid phase. In one form, the temperature control means may comprise one or more heat exchange conduits forming a path or fluid paths for circulation of the heat exchange medium within the chamber. In order to further regulate the circulation of the contents of the camera, the circulation means may further comprise diverters. The deviators can be located within the camera and can be placed in a mode to further improve the circulation of the contents of the camera. In an especially preferred form, the control element can be of an appropriate shape such that the deviators (when present) can be formed integrally with the temperature control means or alternatively the temperature control element can perform a double paper, temperature regulation inside the chamber and provision of diverter elements. The bioreactor may also include a pH control means to control the pH of the liquid phase. The pH control element preferably comprises a pH probe located in the liquid phase, the probe is functionally placed at a C02 supply. The pH of the liquid phase can then be adjusted by controlling the delivery of C02 or by the addition of other chemicals. In some situations, the diffusion of natural light within the camera may also be less optimal and in these situations it may be beneficial to improve the distribution of light within the camera. In this aspect the bioreactor is preferably located on a light reflecting base, the base ensures that the light delivered to the chamber from an external source is maximized.

Additionally or in the alternative, the bioreactor may contain one or more light conducting elements, which promote the effective distribution of light in the reactor. The light conducting element can be located inside the bioreactor or be external to the bioreactor. If sunlight is located inside the bioreactor, it may be suspended above the liquid phase of the submerged in the liquid phase. If the light source is located external to the bioreactor, it can be placed anywhere around it. Preferably the light source is located below the side walls of the bioreactor. In a highly preferred form of the invention, the bioreactor may be suspended or placed within a light box where the lack of light is angulated substantially perpendicular to the sides of the container. In a preferred embodiment of the invention, the bioreactor may also include one or more jacket elements, which is capable of at least partially covering the external surface of the bioreactor. When present, the jacket element can provide an additional means for isolating the bioreactor. While any means known in the art can be used to support the sleeve around the external surface of the bioreactor, the sleeve is preferably mounted on the external wall of the bioreactor via a skeleton or slit fixed to the chamber. The skeleton or slit can also be made of any material such as wood, metal or plastic and preferably be constructed with large openings which allow the penetration of light into the bioreactor chamber. Although the jacket element may be formed of any material that is suitable for isolating the chamber, it is preferably made of a transparent material which allows light to enter the bioreactor. It will be appreciated that the jacket element can provide a means for externally heating or cooling the bioreactor. In this instance the jacket element is preferably attached to the skeleton or lattice arrangement to the outer wall of the bioreactor and to the base of the bioreactor. Preferably the jacket element is sealed in such a way that it is capable of maintaining a heat exchange medium. For example, the jacket element may comprise a transparent flexible polyethylene or polyvinyl film, which is in sealing engagement with the outer frame skeleton which may be attached to the bioreactor. Hot or cold air can then be circulated between the jacket element and the external surface of the bioreactor by means of one or more pumping elements. Said pumping elements are preferably connected to one or more control elements which are able to monitor the internal temperature of the bioreactor and adjust the temperature of the circulating air to maintain a temperature inside the chamber. This control element must also be connected to the heat exchanger. In addition to or as an alternative to the jacket element, a light control means can be provided on the external surface of the bioreactor which is capable of adjusting the amount of light that is introduced into the chamber. While any known means for this purpose may be employed, the light control element preferably consists of a series of shutters which may be open or closed to vary the amount of light that is introduced into the chamber. More preferably, said light control element is connected to one or more light measuring elements. When the amount of light measured by this means exceeds a preset reference value, the control means, for example, will close the light control element for a period of time, after which it will reopen the light control element. The bioreactor may also be in fluid communication with a separate vessel containing the liquid phase. The separate container can act as a reservoir, increasing the volume of the system. It can act as a dark phase area, during high light intensities and growth conditions. Alternatively, it can act as a sedimentation system from which biomass can be removed from the bioreactor. When used in this manner, the bioreactor can be connected to existing technologies to control the flow rate of the liquid phase within the settling vessel to improve settling of the biomass in the settling vessel. The biomass can then be removed continuously or intermittently, with the sedimented material collected and processed. This procedure can serve as a harvesting system to remove biomass from the system and maintain optimum cell densities within the liquid phase. The bioreactor can also be used in several locations that experience a variety of weather conditions. The internal environment of the container and the conditions experienced by its biomass are preferably kept constant and optimal for cell growth, survival, or the induction of specific biochemical processes within the crops. This can be done using a closed system bioreactor where undesirable organisms can be excluded and the physical-chemical environment of the liquid phase inside the bioreactor can be controlled artificially. The control of the physical-chemical conditions within the bioreactor can be achieved using standard computer controls and electronic sensors. The chemical products for the maintenance of nutrient levels and for the control of pH and other factors can be added automatically directly in the liquid phase inside the bioreactor. Computer controls can also control the temperature of the liquid phase inside the bioreactor vessel either by controlling the heat exchange system within the bioreactor or by removing crop from the main vessel and passing it through the heat exchanger in, for example , a water bath with controlled temperature. The removal and passage of the liquid phase containing biomass from the bioreactor to another vessel containing a gas delivery system and back to the bioreactor can be used to increase the concentration of dissolved carbon dioxides in the liquid phase. In this way the biomass can be diverted through a retention contactor or bubbling trawl, or other means to dissolve the carbon dioxide or other gases in the liquid phase without losses to the environment or stress the biomass in the reactor. The withdrawal and passage of the liquid phase can also be used to control the temperature of the liquid phase. In this way the liquid phase is conducted through a container containing at least one temperature control means which is capable of varying the temperature of the liquid phase, before being returned to the bioreactor. The present invention may be either as a single bioreactor chamber or as multiple chambers of which all are interconnected. If multiple cameras are provided, then one or more of the cameras can be synchronized in the dark to assist in the control and manipulation of dark phase growth and respiration. In this instance, the flow of the liquid phase between the chambers is controlled preferably by a computer element which is able to monitor the cellular density within each chamber and is capable of transferring the liquid phase (including biomass) between the chambers in response to changes in cell density. It is understood that bioreactors of the type described herein can be used on a batch basis where a single crop of biomass can be grown in the reactor at a time, or can be used in a continuous production cycle where there is a stationary supply of essential nutrients and liquid phase within the bioreactor as well as a continuous discharge of the liquid phase containing the biomass grown from the bioreactor. In a single-run operation, the nutrients can be added to the chamber of the bioreactor, mixed well with a solution containing biomass, and then left for a period of time until the density of the biomass is achieved. This resulting mixture can then be removed from the bioreactor by processing. Notably, this form of operation leads to a relatively non-stationary environmental state within the bioreactor chamber because the concentration of nutrients and cell density varies with time. As an alternative, during an operation sequence whose duration may depend on the nature and intensity of the irradiation of the light, the concentration of the nutrient solution and the biomass in the liquid phase, the growth ratios can be maintained by adding the nutrients essential to the liquid phase. Preferably the essential nutrients for growth and propagation of the biomass are added to the chamber of the bioreactor as they are consumed by the biomass. To effectively monitor such nutrients, preferably one or more measuring means are present within the bioreactor chamber which are capable of detecting variations in nutrient levels. More preferably, the measuring means are connected to a computer control element which is capable of monitoring the levels of nutrients in the liquid phase and when necessary, capable of introducing nutrients into the bioreactor chamber. If a large number of biomass is required (ie for commercial production of biomass) the bioreactor chamber is preferably operated in a continuous production cycle where there is a stationary supply of new nutrients within the chamber as well as a steady state of biomass. If multiple reactors are connected in series, the first bioreactor may be provided with a stationary supply of new reagents. A continuous flow of reactive materials can then be passed from one bioreactor to the next. The cultivated biomass can then be discharged continuously from the last of the series of bioreactors. In some circumstances it may be useful to introduce additional nutrients or other compounds to several bioreactors in the sequence (eg, when a bioreactor becomes depleted of such nutrients or other compounds). The complete mixing of the content of the liquid phase in the bioreactor means that a constant concentration of biomass entering and leaving each reactor can be maintained. This can result in a change in biomass concentration from one reactor to the next. Preferably the concentration of the biomass increases as it passes through the series of bioreactors. An advantage of using a plurality of continuous series bioreactors to produce biomass, apart from the simplicity of construction, is the ease of temperature and pH control. The material that is introduced into a given container immediately becomes a large volume of biomass and due to the agitation, variations in temperature and pH control are minimal. The present invention will now be described in greater detail by way of example, with reference to the accompanying drawings, wherein: Figure 1 is a top perspective view of a bioreactor according to a preferred embodiment of the invention; Figure 2 is a longitudinal cross-sectional view of the bioreactor of Figure 1; Figure 3 is a simplified end view of the bioreactor of Figure 1 with arrows indicating the flow pattern of the liquid phase within the chamber; Figure 4 is a plot of the biomass vs time obtained using the averaged results of two bioreactors separated in a similar way to the bioreactor of figure 1, each of the bioreactors has a capacity of 750 liters with a triangular dimension of 1200mm and length of 1200mm; Figure 5 is a plot of the biomass vs time obtained using the averaged results of two bioreactors separated in a similar way to the reactor of Figure 1, each of the bioreactors has a capacity of 450 liters with a triangular dimension of 600mm and total length of 3000mm; Figure 6 is a graph of biomass vs time obtained using two bioreactors separated in a similar way to the bioreactor of Figure 1, bioreactor # 1 has a capacity of 350 liters. Figure 7 is a graph of the biomass vs time obtained using a bioreactor of similar shape to the bioreactor of Figure 1, each of the bioreactors has a capacity of 3500 liters, a triangular dimension of 900mm and a length of 10 m. The graph shows curves for eight separate runs. Run 1 represents a run conducted on September 29, 1995. Run 2 represents a run conducted on June 14, 1995. Run 3 represents a run conducted on June 29, 1995. Run 4 represents a run conducted on the July 14, 1995. Run 5 represents a run conducted on August 4, 1995. Run 6 represents a run conducted on September 1, 1995. Run 7 represents a run conducted on November 2, 1995. The run 8 represents a run conducted on November 17, 1995. The bioreactor as shown in Figures 1 and 3 and generally indicated by the number 10, comprises a chamber 12 supported by three vertical support members 14, two of which are located at each end of the chamber and the third of which is located in the middle of the chamber 12. The chamber 12 is of a generally inverted triangular cross section and has a cover element a convex 16 that closes the upper portion of the chamber 12. The chamber 12 further comprises a narrow base portion 18 and a pair of side walls 20. A circulation medium in the form of a conduit 22 is located within the chamber toward the portion base 18 of the chamber 12. The conduit 22 has a plurality of perforations 24 through the length of its interior such that the gas introduced into the chamber through the conduits passes out of the perforations in a generally downward direction , thus preventing sedimentation of the particulate material beneath the conduit 22. The conduit 22 of the embodiment extends through the chamber and has portions extending from either end to allow a number of bioreactors to be connected in series. The temperature control element in the form of a pair of conduits 26 is located towards the middle of the chamber 12 and extends the length thereof. The conduits 26 are connected to an external supply of the heat exchange element (not shown). In this way, through the use of a thermostat and the temperature regulation of the heat exchange medium, the temperature of the liquid phase inside the chamber can be regulated and controlled to a certain setting. The cover member 16 provides a pair of vents 28. The vents 28 are located at each end of the cover member 16 and are positioned toward the center of the cover member 16 to be adjacent to the highest part of the convex surface of the element of cover 16. In operation, there is a positive pressure inside the air vents 28 such that there is excess gas flow out of the vents and negligible flow through the vents inside the chamber, thus avoiding contamination by particles in the air having access to the chamber via the vents 28. In operation, the bioreactor according to figures 3 has a distinctive flow pattern of the liquid phase inside the chamber 12. The flow pattern is specifically shown in Figure 3. The air entering the chamber through the conduit 22 is directed downwardly from the bottom portion of the base portion 18 and then proceeds to travel vertically through the chamber. 12 until it meets the interior of the cover element 16. Upon contact with the cover element, the air is driven towards the side walls 20. The excess air leaves the chamber through the vents 28. The passage of air and its interaction with the liquid phase and the internal walls of the chamber 12 causes the liquid phase to circulate according to the arrows detailed in figure 3. The currents established in the liquid phase, which act uan to circulate the liquid phase containing the biomass vertically up through the central region of the chamber 12, through the upper portion of the chamber directly below the cover element 16 and under the chamber directly adjacent to the side walls 20 to conduit 22 and the cycle is repeated.

In addition, the passage of the liquid phase inside the chamber 16 also serves to maintain the clarity of the side walls 20 and the cover element 16 of the chamber 12. The flow of the liquid phase and the slope of the walls of the chamber it prevents the biomass from settling on the walls and the directed movement of the liquid phase reduces the tendency to certain types of biomass such as algae to adhere to the walls of the chamber. The flow of the liquid phase and configuration of the chamber 12 also results in the cover element 16 of the chamber 12 coming into contact with the liquid phase, this avoids the condensation that is formed in the cover element 16. When the biomass containing photoautotrophs the cover element 16 represents a dominant photosynthetic surface, the condensation on the cover element 16 can result in a photosynthetically active radiation loss. It will be noted that this circulation pattern results in the biomass inside the chamber being placed regularly adjacent the cover element 16 and the side walls 20 thus exposing the biomass to the light that is introduced into the chamber. In this regard, it will be noted that while the cell density of the biomass within the chamber is relatively low, the penetration of light into the chamber will be relatively high. The penetration of light within the chamber is significantly reduced as the biomass increases in cell density. In order to maximize the efficiency of light capture, the bioreactor can be oriented in a north-south direction, making the appropriate corrections for altitude at the site, in accordance with the directives established by solar energy collection technologies. Within this basic orientation from north to south, the bioreactors can be configured in parallel and at a separation distance corresponding to twice the triangular dimension of the container. This arrangement facilitates the maximum efficiency of the capture of light by the bioreactor and land use; It is based on the maximum efficiency of 8 hours of direct sunlight, outside of a 12-hour day, without any shadow effect from neighboring tanks. The bioreactor can be designed to be cleaned and disinfected in situ. Preferably, the construction of the bioreactor will reflect the procedures of the food industry, which use food grade materials and also facilitate effective cleaning and disinfection of the container and all associated infrastructure. Preferably, all the entrances to the chamber are sterilized. The air is filtered at 0.2 microns and is also treated with ultraviolet light at the point of supply to the bioreactor. The water and the nutrient medium added to the chamber can be filtered at 0.2 microns and also treated with UV radiation.

The inoculum of the container is preferably allowed to grow under hygienic conditions and added to the bioreactor under hygienic conditions. Within the chamber, the density of the crop can be manipulated to maintain it for continuous or semi-continuous harvesting regimes or also to facilitate batch harvesting systems. The choice of system and harvesting regime depends on at least the nature of the production system, biomass used and the final use of the harvested product. Elongated triangular bioreactors have been tested, substantially longer than the dimensions of the cross-sectional area. It has been found that the biomass growth ratios are not affected relatively by the length of the bioreactor. On the contrary, triangular cross-sectional dimensions seem to be the most important predictor of growth rate. In this way, the present invention can be scaled to very large volumes without significant changes in the growth ratios of the biomass. Figure 4 shows the increase in biomass over time in a 750-liter bioreactor. of capacity having a triangular cross section of length of equal sides of 1200 mm. The 750-liter bioreactor produced 1000 mg of biomass per liter in six days under natural daylight conditions.

Figure 5 shows the increase in biomass over time in a 450 liter bioreactor. capacity with a triangular cross section with side length of 600 mm and which is 3 meters long. The bioreactor of 450 lts. produced 1200 mg of biomass per liter in four days under natural daylight conditions. Figure 6 shows the increase of the biomass over time in a bioreactor of 350 liters. capacity with a triangular cross section with side length of 900 mm and which has 1 mt. of length. The bioreactor of 350 lts. produced approximately 1000-1200 mg of biomass per liter in approximately six days under natural daylight conditions. Figure 7 shows the increase in biomass over time in a bioreactor with 3500 liters. capacity with a triangular cross section with side length of 900 mm and which is 10 meters long. The 3500 liter bioreactor produced approximately 1100 mg of biomass per liter in approximately 14-15 days under natural daylight conditions. The yields of this vessel average 63 mg / L / day in winter (more than four months). The winter months produced averages of 120 mg / L / day. This is equivalent to 19.85 mg / day or 11.95 ton / hectare for the four winter months and 37.8 mg / day or 45.53 ton / hectare during 8 summer months. These figures are calculated for a triangular tank of 900 mm in dimension having a volume of 300 l / m and inside the container arrangement described above, the container arranged in parallel rows 1800 mm apart from the apex of the base to the apex of the base . This arrangement results in a total theoretical volume of 1925 m3 per hectare. It will be appreciated that the invention leads itself to automatic control in particular by means of the computer.

Furthermore, by connecting in series the bioreactor represented in Figure 1 to 3, it is possible to create a continuous cycle of production for the generation of large quantities of biomass. It will be appreciated that there should be additional variations that are apparent to those skilled in the art from the teachings of the foregoing, such variations being considered within the scope of the invention disclosed herein.

Claims (28)

1. REIVI ND IC AC I ON ES 1. A bioreactor for the production of biomass, comprising: (i) a substantially transparent chamber, the chamber being at least appropriate to contain biomass in a liquid phase, and having a base portion, a upper portion and a number of side walls between the base portion and the upper portion, the side walls are configured to diverge generally from the base portion toward the upper portion; and (ii) a circulation means for circulating the contents of the chamber, wherein the circulation means creates an appropriate movement force within the liquid phase to ensure the continuous mixing of substantially all of the biomass and at least the semi-continuous exposure of the biomass. the biomass to a light source. The bioreactor according to claim 1, wherein the rate of circulation within the chamber is at least slightly greater than a circulation ratio that would lead to sedimentation of the biomass within the bioreactor. 3. The bioreactor according to claim 1, wherein the bioreactor is suspended above a reflective base surface. The bioreactor according to claim 1, wherein the circulation medium is located within the bioreactor at or near the base portion. The bioreactor according to claims 1 to 3, wherein the recirculation element is located adjacent to the base portion within the bioreactor and is capable of generating an upward movement of the biomass and the liquid phase from the portion base to the upper portion of the bioreactor whereby the biomass impacts the upper surface of the vessel ensuring the brief exposure to light of most of the biomass in the liquid phase, after which the biomass moves externally to the sides of the bioreactor then down the sides of the bioreactor towards the base portion, from where it is again trapped by the circulation medium and driven upwards towards the top of the bioreactor. The bioreactor according to claim 1, wherein the circulation means is a conduit that extends through the length of the chamber which is located near the base portion of the chamber, said conduit is perforated and connected to a source of gas that in operation the passage of gas out of the conduit and into the chamber causes circulation of the contents of the chamber. 7. A bioreactor for the production of biomass, comprising: (i) a substantially transparent chamber, the chamber being at least appropriate for containing biomass in a liquid phase, and having a narrow base portion, an upper portion capable of being sealed by a cover element and a number of side walls diverging from the base portion to the upper portion; and (ii) a circulation medium for circulating the contents of the chamber, wherein the circulation medium creates an appropriate driving force to ensure the continuous mixing of the liquid phase and exposure of the biomass to light, wherein the medium of The circulation is located at or near the lower portion of the base portion and comprises a conduit extending along the bioreactor, the perforated conduit being connected to a gas source where the perforations in the conduit are disposed toward the underlying side of the duct, such that, in operation, the passage of the gas out of duct and into the liquid phase (a) prevents the particulate material within the chamber from sedimenting under the duct, (b) causing the circulation of the liquid phase; and (c) allows the diffusion of the gas in the liquid phase. 8. The bioreactor according to any of the preceding claims, wherein the bioreactor chamber is an elongated trough type prism, the prism has an inverted cross section, which can accommodate large volumes of liquid phase. 9. The bioreactor according to claim 7, wherein the cover element is slightly arched with a generally convex upper surface inside which is provided one or more vents positioned towards the middle of the convex upper surface which allows the gas to be vented from the chamber. 10. The bioreactor according to claim 9, wherein the vents contain a filter element which is capable of preventing particular material from entering the chamber. The bioreactor according to any of the preceding claims, wherein the bioreactor includes a temperature control element for controlling the temperature of the liquid phase. 12. The bioreactor according to any of the preceding claims, wherein the bioreactor contains at least one diverter which is placed in a mode to further improve the circulation of the contents of the chamber. The bioreactor according to any of the preceding claims, wherein the bioreactor includes a pH control element for controlling the pH of the liquid phase. The bioreactor according to any of the preceding claims, wherein the bioreactor comprises one or more light conducting elements which promote the effective distribution of light within the chamber. 15. The bioreactor according to any of the preceding claims, wherein the bioreactor contains one or more measuring elements, which are capable of detecting variations in nutrient levels. 16. The bioreactor according to claim 15, wherein the measuring elements are connected to a computer control element which is capable of monitoring the levels of nutrients in the liquid phase and when necessary is able to introduce nutrients into the liquid phase. of the bioreactor chamber. 17. The bioreactor according to any of the preceding claims, wherein the bioreactor includes one or more jacket elements which are capable of at least partially covering the external surface of the bioreactor. 18. The bioreactor according to any of the preceding claims, wherein the bioreactor is in fluid communication with a separate vessel through which the liquid phase is diverted before its return to the bioreactor. 19. The bioreactor according to claim 18, wherein the separate container is a reservoir, which increases the volume of the system. 20. The bioreactor according to claim 18 or 19, wherein the separate vessel is a dark phase area that is used during conditions of high light intensity and growth. 21. The bioreactor according to claim 18, wherein the separate vessel is a sedimentation system from which the biomass can be removed from the liquid phase. 22. The bioreactor according to any of the preceding claims, wherein the internal environment of the bioreactor remains constant and optimal for the growth and survival of biomass or for the induction of specific biochemical processes within the biomass, by means of one or more elements of computer, which are able to introduce nutrients or chemicals or modify the light or temperature of the liquid phase in response to a change in one or more of these conditions. 23. The bioreactor according to any of the preceding claims, wherein the liquid phase is pumped through a separate vessel containing a bubbling entrainer or other means for dissolving carbon dioxide or other gases in the liquid phase before returning it to the bioreactor. 24. The bioreactor according to claim 23, wherein the liquid phase is also pumped through a vessel containing a temperature control element which is capable of varying the temperature in the liquid phase before returning it to the bioreactor. 25. The bioreactor according to any of the preceding claims, where the bioreactor includes a multiplicity of cameras of which all are interconnected. 26. The bioreactor according to claim 25, wherein one or more of the chambers are synchronized in the dark to assist in the propagation of the biomass. 27. The bioreactor according to any of claims 27 or 28, wherein the flow of the liquid phase between the chambers is controlled by a computer control element which is capable of monitoring the density of the biomass within each chamber. and which is capable of transferring the liquid phase between the chambers in response to changes in biomass density in each chamber. 28. A method of cultivating biomass comprising the step of growing biomass in a bioreactor according to claim 1, wherein the biomass grows in a continuous cycle of production where there is a stationary supply of essential nutrients and liquid phase within the bioreactor as well as a continuous discharge of liquid phase containing the cultured biomass of the reactor.