WO2014197766A1 - Flexible bioreactors, systems and methods - Google Patents

Abstract

The present invention provides a photobioreactor for a phototrophic microorganism and culture medium therefor. The photobioreactor for a phototrophic microorganism and culture medium may include an elongated capsule having a flexible polymer film that is at least partially transparent to light of a wavelength that is photosynthetically active in a phototrophic microorganism. The elongated capsule can be divided widthwise into a plurality of adjacent channels, each channel being comprised of the flexible polymer film and having in a plurality of positions distributed along a length of the channel a reinforced material bonded with the channel, the reinforced material surrounding part or the entire perimeter of the channel, independently, in the each of the plurality of positions.

Description

FLEXIBLE BIOREACTORS, SYSTEMS AND METHODS

RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Application No.

61/832,598, filed on June 7, 2013. The entire teachings of the above application(s) are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] One of the primary limitations of using photosynthetic microorganisms as a method of carbon dioxide sequestration or conversion to products has been the need for development of efficient and cost-effective growth systems. Open algal ponds up to 4 km² have been researched, which, while requiring low capital expenditures, ultimately have low productivity as these systems are also subject to a number of problems. Intrinsic to being an open system, the cultured organisms are exposed to a number of exogenous organisms that can be symbiotic, competitive, or pathogenic. Symbiotic organisms can change the culture organisms merely by exposing them to a different set of conditions. Opportunistic species can compete with the desired organism for space, nutrients, etc. Additionally, pathogenic invaders can feed on or kill the desired organism. In addition to these complicating factors, open systems are difficult to insulate from environmental changes including temperature, turbidity, pH, salinity, and exposure to the sun. These difficulties point to the need to develop a closed, controllable system for the growth of algae and similar organisms.

[0003] Not surprisingly, a number of closed photobioreactors have been developed. Typically, these are cylindrical or tubular (i.e., U.S. Pat. No. 5,958,761, U.S. Patent application No. 2007/0048859). These bioreactors often require mixing devices, increasing cost, and are prone to accumulating oxygen (0₂), which inhibits algal growth.

[0004] Tubular bioreactors, when oriented horizontally, typically require additional energy to provide mixing (e.g., pumps), thus adding significant capital and operational expense. In this orientation, the 0₂ produced by photosynthesis can readily become trapped in the system, thus causing a significant reduction in organism proliferation. [0005] Several flat-plate photobioreactor designs have been disclosed for culturing microalgae: Samson, R. & Leduy, A. (1985), Multi-stage continuous cultivation of blue- green alga Spinilina maxima in the flat tank photobioreactors with recycle. Can. J. Chem. Eng. 63 : 105-1 12; Ramos de Ortega and Roux, J.C. (1986), Production of Chlorella biomass in different types of flat bioreactors in temperate zones. Biomass 10: 141-156; Tredici, M. R. and Materassi, R. (1992), From open ponds to vertical alveolar panels: the Italian experience in the development of reactors for the mass cultivation of photoautotrophic microorganisms. J. Appl. Phycol 4: 221-31 ; Tredici M.R., Carlozzi P., Zittelli G.C. and Materassi R. (1991), A vertical alveolar panel (VAP) for outdoor mass cultivation of microalgae and Cyanobacteria. Bioresource Technol. 38: 153- 159; Hu Q. and Richmond A. (1996), Productivity and photo synthetic efficiency Spirulina platensis as affected by light intensity, organism density and rate of mixing in a flat plate photobioreactor. J Appl. Phycol. 8: 139-145; Hu Q, Yair Z. and Richmond A. (1998) Combined effects of light intensity, light-path and culture density on output rate of Spirulina platensis (Cyanobacteria). European Journal of Phycology 33: 165-171 ; Hu et al. WO 2007/098150. However, to date, no design or system has been successfully scaled up for efficient growth of organisms in commercial scale.

[0006] Many different photobioreactor configurations have been described in the literature including flat panels, bubble columns, tubular reactors and a variety of annular designs aimed at improving the surface area to volume ratio to maximize conversion of sunlight and C02 to biomass or other products such as algal oil. These reactors have distinct advantages compared to open raceway with respect to controlling temperature, H, nutrients and limiting contamination (see Pulz, O. "Photobioreactors: Production systems for phototrophic microorganisms," Appl. Microbiol Biotechnol (2001) 57:287-293). Key limitations to their adoption have been the cost vs. benefit as it relates to the product being produced. Whereas valuable products such as carotenoids have been produced in

photobioreactors, the production of biomass for fuels could not be economically justified to date.

[0007] Thin-film polymeric photobioreactor capsules have a number of advantages, for example, low manufacturing costs, low weight and ease of transportation in uninflated form. However, when culture medium is flown into these capsules, the capsules can inflate to the extent of damaging the capsule (typically, at seams and welds which have been formed, e.g., to provide channels in the middle section of the capsule). Particularly in the case of channeled thin-film polymeric capsules, culture medium flow from the inlet is preferably equidistributed into the channels of the thin-film polymeric capsules.

[0008] What is needed, therefore, is an integrated photobioreactor system that is scalable, low cost, and efficient for culturing light-capturing organisms, and more specifically, photobioreactors which exhibit improved culture medium flow management to improve culture medium flow into and through the photobioreactor capsules and improved structural stability to reduce the potential for inflation that could damage the thin-film capsule, particularly, at high operating pressures. Additionally, the photobioreactor system may need to have low material costs and provide for easy deployment.

SUMMARY OF THE INVENTION

[0009] The present invention provides photobioreactors that include a thin-film elongated capsule which exhibits improved culture medium flow management to improve culture medium flow into and through the photobioreactor capsules while improving structural stability to reduce the potential for inflation that could damage the thin-film capsule.

Additionally, these capsules are low weight and can be easily transported.

[0010] These two advantages are achieved by including one or more flexible polymer sections within the elongated capsule as described herein. To prevent potentially damaging inflation of the flexible enclosure of the capsule, the one or more polymer sections hold an internal top surface and internal bottom surface of the flexible enclosure together (typically, the flexible polymer section is bonded, e.g., welded to the internal surfaces of the flexible enclosure) by being suitable dimensioned to prevent a potentially damaging inflation of the flexible enclosure of the thin-film capsule and to reduce associated forces on bonded areas, e.g., seams and welds of the capsule.

[0011] One embodiment of the present invention is a photobioreactor for a photo trophic microorganism and culture medium therefor, comprising an elongated capsule comprised of a flexible polymer film which is at least partially transparent to light of a wavelength that is photosynthetically active in the phototrophic microorganism, wherein the flexible polymer film provides a flexible enclosure having an internal top surface and an internal bottom surface of the elongated capsule. The elongated capsule further comprises (a) an inlet for flowing culture medium into the elongated capsule; (b) an outlet for flowing culture medium out off the elongated capsule; and (c) a plurality of flexible polymer film sections within the elongated capsule; (i) each flexible polymer film section bonded along a first edge of the flexible polymer film section to the internal top surface and along a second edge of the flexible polymer film section, which is opposite to the first edge, to the internal bottom surface; (ii) each flexible polymer film section, independently, having a plurality of openings; (iii) at least one (and, preferably, each) of the flexible polymer film sections being

dimensioned to constrain the inflatable volume of the flexible enclosure; and (iv) the plurality of flexible polymer film sections being in positions distributed along a length of the elongated capsule.

[0012] A further embodiment of the present invention is a photobioreactor for a phototrophic microorganism and culture medium therefor, comprising an elongated capsule comprised of a flexible polymer film which is at least partially transparent to light of a wavelength that is photosynthetically active in the phototrophic microorganism, wherein the flexible polymer film provides a flexible enclosure having an internal top surface and an internal bottom surface of the elongated capsule. The elongated capsule further comprises (a) an inlet for flowing culture medium into the elongated capsule; (b) an outlet for flowing culture medium out off the elongated capsule; and (c) a flexible polymer film sections within the elongated capsule; (i) the flexible polymer film section bonded along a first edge of the flexible polymer film section to the internal top surface and along a second edge of the flexible polymer film section, which is opposite to the first edge, to the internal bottom surface; (ii) the flexible polymer film section, independently, having a plurality of openings; (iii) the flexible polymer film section being dimensioned to constrain the inflatable volume of the flexible enclosure; and (iv) the flexible polymer film section being positioned adjacent to the inlet.

[0013] Yet a further embodiment of the present invention is a photobioreactor or bioreactor, system, or method thereof. The photobioreactor can have an elongated capsule comprised of a flexible polymer film which is at least partially transparent to light of a wavelength that is photosynthetically active in the phototrophic microorganism. The flexible polymer film can provide a flexible enclosure having an internal top surface and an internal bottom surface of the elongated capsule. The elongated capsule can further have an inlet for flowing culture medium into the elongated capsule, an outlet for flowing culture medium out off the elongated capsule, a plurality of flexible polymer film sections within the elongated capsule, and/or each flexible polymer film section bonded along a first edge of the flexible polymer film section to the internal top surface and along a second edge of the flexible polymer film section, which is opposite to the first edge, to the internal bottom surface. Each flexible polymer film section can independently have a plurality of openings. Each flexible polymer film section can have a length, measured perpendicularly from the first edge to the second edge, which is shorter than a distance, perpendicular from the internal bottom surface to the internal top surface, that would be measured in the absence of the polymer film section when the capsule is inflated. The plurality of flexible polymer film sections can be in positions distributed along a length of the elongated capsule.

[0014] Other embodiments include one or more of the following variations. The flexible polymer film sections can be distributed along the entire length of the capsule. The elongated capsule can be a capsule without a plurality of adjacent channels. The elongated capsule can have a first region extending from an inlet to a second region, wherein the elongated capsule may be divided widthwise into a plurality of adjacent channels in the second region, each channel being comprised of the flexible polymer film. The plurality of flexible polymer film sections can be positioned in the first region. At least one of the plurality of flexible polymer film sections may be oriented along the width of the capsule or extends across the width of the capsule. The flexible polymer film sections of the plurality of flexible polymer film sections may have different numbers of openings. The openings of the flexible polymer film sections may increase in number from a first of the plurality of polymer film sections closest to the inlet to a second of the plurality of polymer film sections. The openings may have an average size smaller than the inlet. The average distance of adjacent polymer film sections of the plurality of polymer film sections may be uniform along the length of the capsule from the inlet towards the outlet. The average distance of adjacent polymer film sections of the plurality of polymer film sections may increase along the length of the capsule from the inlet towards the outlet. At least one of the plurality of polymer film sections may be bonded along its entire perimeter to an inside surface of the flexible enclosure. At least one of the plurality of polymer film sections may only be bonded along part of its entire perimeter to an inside surface of the flexible enclosure. At least two of the plurality of polymer film sections may be oriented along the width of the capsule, and positioned side by side, jointly spanning part or the entire width of the capsule. At least two of the plurality of polymer film sections may be positioned to provide gaps between the two polymer film sections.

[0015] The present invention is not intended to be limited to a system or method that must satisfy one or more of any stated objects or features of the invention. It is also important to note that the present invention is not limited to the exemplary or primary embodiments described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.

[0017] FIG. 1 is a profile block diagram of a photobioreactor constructed in accordance with an exemplary embodiment of the invention.

[0018] FIG. 2A is a top profile view diagram of a reactor chamber constructed in accordance with an exemplary embodiment of the invention.

[0019] FIG. 2B is a cross section diagram of the photobioreactor along line A in FIG. 2A constructed in accordance with the exemplary embodiment of the invention.

[0020] FIG. 2C is a cross section diagram of the photobioreactor along line B in FIG. 2A constructed in accordance with the exemplary embodiment of the invention.

[0021] FIG. 2D is a cross section diagram of the photobioreactor along line C in FIG. 2A constructed in accordance with the exemplary embodiment of the invention.

[0022] FIG. 2E is a cross section diagram of the photobioreactor along line D in FIG. 2A constructed in accordance with the exemplary embodiment of the invention.

[0023] FIGS. 3A, 3B, and 3C are top profile view diagrams of exemplary reactor channel configurations constructed in accordance with various additional exemplary embodiment of the invention.

[0024] FIGS. 4A and 4B are a cross section diagram of the photobioreactor along line D in FIG. 2A constructed in accordance with various additional exemplary embodiment of the invention.

[0025] FIGS. 5 A and 5B are top profile view diagrams of exemplary reactor channel configurations constructed in accordance with various additional exemplary embodiment of the invention.

[0026] FIG. 6A is a top profile view diagram of a reactor chamber constructed in accordance with an exemplary embodiment of the invention. [0027] FIG. 6B is a cross section diagram of the photobioreactor along line A in FIG. 6A constructed in accordance with the exemplary embodiment of the invention.

[0028] FIG. 7 is a perspective view of a reactor chamber constructed in accordance with an exemplary embodiment of the invention.

[0029] FIG. 8 is a top profile, partial view and schematic diagram of an elongated capsule connected to an inlet, constructed in accordance with an exemplary embodiment fo the present invention.

[0030] The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0031] A description of preferred embodiments of the invention follows. The relevant teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety. The following explanations of terms and methods are provided to better describe the present invention and to guide those of ordinary skill in the art in the practice of the present invention. As used herein, "comprising" means "including" and the singular forms "a" or "an" or "the" include plural references unless the context clearly dictates otherwise. For example, reference to "comprising a phototrophic microorganism" includes one or a plurality of such phototrophic microorganisms. The term "or" refers to a single element of stated alternative elements or a combination of two or more elements, unless the context clearly indicates otherwise.

[0032] Unless explained otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. The materials, methods, and examples are illustrative only and not intended to be limiting. Other features of the invention are apparent from the following detailed description and the claims.

[0033] General

[0034] Referring to FIG. 1 , an exemplary photobioreactor 100 includes a horizontally oriented reactor chamber 102 and a circulation driver 104 to provide circulation. The circulation driver 104 provides a flow of material in the thin-film photobioreactor, which can be made of translucent material for light of a wavelength that is photosynthetically active to the microorganisms. The reactor chamber 102 can be a thin-film photobioreactor with a high aspect ratio (flat). The culture medium and organism can circulate through the reactor chamber 102 and maximize exposure via the increased high aspect ratio. After circulating through a loop of the reactor chamber 102, the culture medium and organism can exit into the circulation driver 104 and back into the entrance of the reactor chamber 102. The reactor chamber 102 can be designed in an elongated loop with a path extending away from the circulation driver 104 and returning via a return path parallel from the away path.

Embodiments are not limited to one circulation driver or an enclosed loop as shown in FIG. 1. Exemplary embodiments can utilize multiple circulation drivers 104 and/or can comprise a single directional flow.

[0035] Example circulation drivers 104 are not limited to utilizing an induced circulation system, for example, gravity driven, tidal driven, air driven, thermally driven, or circulation systems that do not involve active contact with the material being circulated. Exemplary circulating drivers 104 can also utilize active circulation devices such as pumps or augers that actively apply a contact and apply a force to the circulating material.

[0036] Embodiments of the invention can maintain an environment that allows for microorganisms to operate at their highest productivity in the reactor chamber 102. A couple of the key characteristics of this environment, among others, can include:

[0037] 1) maximizing the surface area of the culture medium that the microorganisms are suspended in to increase photon absorption; and

[0038] 2) maintaining a thin culture layer to increase photon absorption as well as providing for short light-dark cycle times and efficient heating ramp up of the culture.

[0039] Exemplary embodiments of the reactor chamber 102 design can utilize a collapsible elongated capsule constructed of polymer film approximately 1 meter wide by 100 meters in length. The culture medium, microorganisms and gases can be introduced into the reactor chamber 102 via an inlet port fitting at one end of the reactor chamber 102 and exit via an outlet port fitting at the other end. An internal pressure can be created by the culture medium, microorganisms and gases. If the pressure is sufficiently high and the reactor chamber 102 is left unrestrained, the pressure can cause the reactor chamber 102 to inflate into a long tubular shape. The culture follows the resulting path of the inflated reactor chamber 102 and takes on a semi-circular shape cross section. This semi-circular cross section can have a predetermined diameter and chord length associated with it. If the semi- circle is translated along the length of the capsule, the diameter corresponds to some culture depth and the chord length corresponds to a culture surface area. As previously explained, it it typically is desirable to maximize the surface area and minimize the depth of the culture. Embodiments can be used to construct a semi-circular cross section to that of a short and wide rectangle or elliptical shape.

[0040] Embodiments for restraining the flexible walls from inflating into one channel with a large diameter semi-circle comprise welded or heat sealed seams providing multiple individual channels along the length of the elongated capsule. These channels break the width of the elongated capsule up into several smaller channels or tubes that, when pressurized, will inflate to smaller diameters. When the culture medium and microorganisms are introduced into these channels, the resulting culture depth can be decreased. The ratio of corresponding cross-sectional area to the culture depth can also be increased providing for increased photon absorption.

[0041] Reactor Chamber

[0042] As shown in FIGS. 2A and 2B, a top profile diagram and a cross-section diagram of an illustrative thin-film elongated capsule 202 in accordance with the present invention, according to certain embodiments, are shown. The thin-film elongated capsule 202 includes one or more channels (206A, 206B, 206C, and 206D). The elongated capsule 202 is adapted to allow cultivation in the culture medium of the phototrophic microorganisms. Phototrophic organisms growing in photobioreactors can be suspended or immobilized. Typically, the channel size is between 0.2 to 5 cm in diameter (more particularly, between 2 cm and 4 cm) with the layer of culture medium of the phototrophic microorganisms between about 5 mm and about 30 mm thick, or, more typically, between about 10 mm and about 15 mm. By inflating the elongated capsule 202 to predetermined amounts with a number of channels across the width of the elongated capsule 202, the desired thickness of the layer of phototrophic microorganisms can be achieved. A substantial even layer can have a thickness with various depths ranging between about 5 mm to about 30 mm thick for a substantial surface area portion of the layer, or, more typically, between about 10 mm to about 15 mm.

[0043] The elongated capsule 202 can be provided by a thin- film material enclosure, typically made from a polymeric material. The phototrophic microorganisms contained in photobioreactors for growth and/or the production of carbon-based products of interest can require light. Therefore, the photobioreactors and, in particular, the elongated capsule are adapted to provide light of a wavelength that is photosynthetically active in the phototrophic microorganism to reach the culture medium. Typically, a top sheet 208 and a bottom sheet 210 are welded lengthwise along both outside edges 212. The surface of the top sheet 208 facing the bottom sheet 210 is the internal top surface of the elongated capsule, and the surface of the bottom sheet 210 facing the top sheet 208 is the internal bottom surface of the elongated capsule.

[0044] Seams 214 can be welded or sealed lengthwise between the top sheet 208 and the bottom sheet 210 to provide the four channels 206 A-D (here, four channels are shown;

however, generally, the embodiments of the present invention can have a plurality of channels, for example, between two and fifty channels). The seams can be produced using a variety of known heating or welding techniques to produce the desired seam, for example, conductive, laser, microwave, ultrasonic weld, or chemical welding devices and methods. In addition to welding the seam, other techniques can be used to join the top and bottom sheet, for example, but not limited to adhesives or fasteners.

[0045] Other embodiment can include the use of blown films that are manufactured as a collapsed tube. The blown films can have the shape of multiple channels or include individual channels of blown films that coupled together. The coupling can be provided by using a variety of known heating or welding techniques to produce the desired connection, for example, conductive, laser, microwave, ultrasonic weld, or chemical welding devices and methods. In addition to welding the connection, other techniques can be used to join the multiple channels, for example, but not limited to adhesives or fasteners.

[0046] The top sheet 208 can include no structural support elements. Embodiment can utilize only the internal pressure within the elongated capsule 202 to support the top sheet 208 above the culture medium and microorganisms. The top sheet can be collapsed onto itself when the culture medium, microorganisms and/or gases are removed from the elongated capsule 202.

[0047] The elongated capsule 202 is not limited to four channels and can have as many or as few as desired according to the intended design constraints of the elongated capsule 202. These design constraints can include, for example, the width of the channel by seams, end region geometry, total width of the reactor chamber, flow characteristics, mechanical stress on the elongated capsule, and/or other characteristics of the elongated capsule 202. The channels 206A-D are also not limited to a straight path as shown in FIGS. 2A and 2B.

Embodiments can utilize curved seams 214 that produce winding paths or channels with varying widths. The channels 206A-D can be a variety of different shapes and sizes. Each channel 206A-D of a photobioreactor can be of a different shape and dimension. Typically, however, in an elongated capsule 202 with a plurality of channels 206A-D, the channels are of similar or identical shape and dimensions, for example, channels positioned in parallel with substantially longer channel length than width. Various reactor chamber cross-sections are suitable, for example, cylindrical or half-elliptical. Preferably, the reactor chamber is half- elliptical or rectangular.

[0048] The elongated capsule is not limited to both top and bottom sheets of flexible material. In one embodiment the bottom sheet can be a relatively rigid material with a flexible material coupled to the edges and seams as previously described to provide the channels. Typically, however, the elongated capsule can be enclosures (e.g., bags) welded from thin polymeric films. Such elongated capsule can allow for advantageous compact transport, facilitate sterilization (e.g., with radiation such as gamma radiation) prior to deployment, and allow use as disposable reactor chamber(s) because of the cost-efficiency and/or energy efficiency of their production. They can also be reused.

[0049] The top sheet 208 can be transparent for light of a wavelength that is

photosynthetically active in the phototrophic microorganism. This can be achieved by proper choice of the material, for example, thin-film material for the top sheet 208 to allow light to enter the interior reactor chamber. The bottom sheet 210 can be provided by a thin-film material enclosure, typically made from a polymeric material with great abrasion resistance. In applications in which the bottom sheet 210 can rest directly on the ground, the bottom sheet can include a polymeric material of great thickness, multiple layers, and/or additional features that can prevent abrasions or tears due to contact of coarser material, such as, gravel, or other object on the ground. These features can include, but are not limited to, impregnated mesh and/or rubberized or other protective coatings. The bottom sheet 210 can also incorporate a reflective internal surface to allow light that has passed through the elongated capsule 202 to be reflected back through the elongated capsule 202 and allow the

phototrophic microorganism to better capture the light. Embodiments can include the top sheet 208 and the bottom sheet 210 being encapsulated with additional independent top and bottom enclosures that provide the abrasion resistance and/or other characteristics that protect the elongated capsule 202 from the external environment while allowing passage of wavelength of light for photosynthetic activity.

[0050] The inflating process to predetermined amounts can occur before, during, or after the introduction of the culture medium and/or microorganisms being introduced into the elongated capsule 202. The predetermined amount can be designated by a specific pressure, amount of particles, volume or other unit. The predetermined amount is not limited to a specific quantity but can be determined using, for example, algorithms, or can be determined and adjusted in real-time.

[0051 ] The photobioreactor described herein can be placed on the ground or float on water such that the top sheet 208 is directed upwards and the bottom sheet 210 can be placed on the ground. Alternatively, the photobioreactor(s) can also be placed above the ground and can utilize solid support structures made of, for example, wood, metal, mesh or fabric. Other support structures can include, for example, stakes, anchors or cables attached to flaps along the edges of the photobioreactor. In one exemplary embodiment, straps or loops are provided along both edges of the photobioreactor. The straps or loops can use stakes or anchors to secure the photobioreactor to the ground or other surface. The straps or loops can be of the same material as the bottom sheet 210. The straps or loops can be molded into or adhered to the seam 214 or coupled to holes provided in the center of the seam 214 such that a seal is provided around the hole and within the seam. The support structures can be used to prevent rotation or movement of the photobioreactor. The support structure can be used to prevent movement due to gravity, unintended external forces and/or inclement weather.

[0052] The photobioreactors can include a number of devices that can support the operation of the photobioreactors. For example, devices for flowing gases (e.g., carbon dioxide, air, and/or other gases), measurement devices (e.g. optical density meters, thermometers), inlets and outlets, and other elements can be integrated or operationally coupled to the photobioreactor. The elongated capsule 202 can include further elements (not shown) such as inlets and outlets, for example, for growth media, carbon sources (e.g., C02), and probe devices such as optical density measurement device and thermometers.

[0053] Further, the elongated capsule 202 can be adapted to allow gas flow through the various channels 206 A-D. Gas (e.g. C02) flow can be co- and/or counterdirectional to liquid flow through the reactor. For example, in certain embodiments, the photobioreactors are adapted to allow codirectional gas flow in one part of the reactor chamber and

counterdirectional gas flow in another part of the reactor chamber. In other embodiments, one or more reactor chambers of a photobioreactor are adapted to allow codirectional gas flow, and one or more other reactor chambers of the photobioreactor are adapted to allow counterdirectional gas flow. The sheets of material separating the reactor and support chambers can also be designed to allow passage of gas while preventing passage of liquids, culture medium, and/or microorganisms.

[0054J In additional embodiments, support straps or a sheet can be used to further allow for a desired shape of the channels 206A-D. The support straps can be strips of polymeric material or cords across the width of the channels 206A-D. As the channels 206A-D are inflated, the support straps can be brought into tension providing more of a rectangle shape with a desired thickness to the channels 206A-D. The support straps or sheet can also be a mesh sheet or other sheet of material with various openings. The support straps can be incorporated in the manufacturing of the reactor chamber design by placing the straps or threads between the top and bottom sheets 208, 210 of thin film of the elongated capsule 202. The straps or threads can be coupled to the outer edges during an edge sealing process. The sealing process can weld or adhere the straps or threads between the top and bottom sheets 208, 210.

[0055J Internal Structure

[0056] The thin-film elongated capsule 202 includes an inlet 204 feeding two or more channels 206A-D and an outlet 205 for receiving the culture medium and microorganisms from the two or more channels 206A-D. The inlet 204 and outlet 205 allow the elongated capsule to be connected to the circulation driver 104, another elongated capsules 202 and/or other equipment. As shown in FIGS. 2C, 2D and 2E, a cross-section diagram of various illustrative internal structures in accordance with the present invention, according to certain embodiments, are shown.

[0057] Thin-film sections (also referred to herein as "flexible polymer film sections) 216B, 216C, and 216D or thin- film sections 218 are positioned between the top sheet 208 and bottom sheet 210 to provide internal walls. The thin-film sections 216B, 216C, and 216D are bonded along a first edge 222 of the thin-film section to an internal top surface of the top sheet 208. The thin-film sections 216B, 216C, and 216D are also bonded along a second edge 224 of the thin- film section to an internal bottom surface of the bottom sheet 210 with the second edge being opposite the first edge. While the top sheet 208 and the bottom sheet 210 of the flexibe capsule can contact each other or be in close proximity when the capsule is not inflated, upon inflation the top sheet 208 and bottom sheet 210 become more distant (typically, when the bottom sheet 210 is supported on the ground, the top sheet 208 moves away from the bottom sheet. In the absence of the flexible polymer sections the capsule can fully inflate (i.e., inflate to an extent that leads to damage of the capsule, e.g. rupture of seams or welds). To prevent damage and, optionally, allow higher flow pressure through the capsules, the inflatable volume of the capsule is constrained with one or more flexible polymer sheets. Although the foregoing is described in the context of FIGS. 2 A to 2E, it generally applies to the embodiments described herein. The thin-film sections can distributed along the length of the elongated capsule 202.

[0058] The thin- film sections 216B, 216C, and 216D can include openings 220 to control the flow through each respective thin-film section 216B, 216C, and 216D. The openings 220 can be sized and positioned to allow the flow to be distributed (preferably, to support even distribution) between the multiple channels 206 A-D. According to the embodiments shown in FIGS. 2C, 2D and 2E, each of the thin-film sections 216B, 216C, and 216D can have openings 220 positioned to direct the flow of the culture medium and microorganisms evenly across the multiple channels 206A-D. As shown when viewing each of FIGS. 2C, 2D and 2E, each group of openings 220B feed two groups of openings 220B in the successive thin- film section. The result is that the openings 220B-C direct the flow of the culture medium and microorganisms from the inlet 204 to each of the four channels 206A-D in a manner supporting even distribution among the channels. The distribution can be designed to provide a substantially even distribution between the channels or can be designed to favor circulation to certain channels. A substantially even distribution allows for mixing and even amounts to be dispersed to each of the channels 206 A-D.

[0059] Embodiments are not limited to the thin-film sections 216B, 216C, and 216D running perpendicular to the flow of the culture medium and microorganisms or

perpendicular to thin-film elongated capsule 202. The thin- film sections 316A, as shown in FIG. 3A can, for example run at an angle to the flow of the culture medium and

microorganisms or to the channels 306 thin-film elongated capsule 302. Embodiments utilizing angled thin-film sections 316A can be used, for example, to provide mixing of the culture medium and microorganisms. According to another embodiment, the thin-film sections 316B, as shown in FIG. 3B, can be designed to direct the flow of the culture medium and microorganisms to the channels 306 of the thin-film elongated capsule 302 in view of the position of the inlet or outlet. As shown in FIG. 3B, the thin-film section 316B can be used to disperse the flow from a direction entering left of the elongated capsule 302. At successive angles, the thin-film sections 316B can be used to direct the flow to the right and evenly distribute the flow of the culture medium and microorganisms to the thin-film elongated capsule 302. Embodiments are not limited to a specific direction, for example, the inlet or outlet may be positioned on the right and the thin-film sections 316B positioned at successive angles to direct the flow evenly to the left. In additional embodiments (not shown), the thin- film sections 316B can be used to direct the flow from an inlet or outlet position at the top or bottom. In these additional embodiments, the thin-film sections 316B can be positioned at successive angles from top to bottom.

[0060] The thin-film sections 316C, as shown in FIG. 3C can, for example run at multiple angles to the flow of the culture medium and microorganisms or to the thin-film elongated capsule 302. The thin-film sections 316C run at multiple angles and are symmetrical about the center of the center of the photobioreactor. Embodiments utilizing multiple angled thin- film sections 316 can be used, for example, to provide distribution to the edges of the photobioreactor or reduce stress impact on the outer seams of the photobioreactor.

Embodiments are not limited to two angles and may, for example use a zigzag pattern to better distribute the flow. In addition, embodiments are not limited to fixed changes in direction of the thin-film sections 316C. Additional embodiment can use curves or rounded paths to reduce or eliminate stress points or points of flow stagnation.

[0061] Embodiments are not limited to the displayed patterns and can utilize various combinations and patterns not shown. The position of thin-film sections is not limited to the above described embodiments. The thin-film sections 316 can incorporate a variety of position and shapes based on the design of the photobioreactor. Additionally, the thin-film sections 316 are not limited to specific numbers as shown and described in previous embodiments. The number of thin-film sections 316 can be, for example, limited to a single section at the inlet, at the outlet, or both. The thin-film sections 316 can include multiple sections at each inlet and outlet and are not limited to having an equal numbers at the inlet and outlet or, for example, embodiments can have six at the inlet and only utilize one at the outlet. The number and placement of thin-film section 316 can be designed based on, for example, the desired distribution or mixing, the desired structure of the photobioreactor, or the designed to reduce stresses imparted on portion/structures of the photobioreactor.

[0062] In addition, to placement and shape of the thin-film sections 316, embodiments may also incorporate a variety of opening shapes and placement of openings. As shown in FIGS. 4A-C , the embodiments provide openings 220B-D with each group including three circular shaped openings in the thin-film sections 216B-E. However, embodiments may not be limited to a specific number or shape. As shown in FIG. 4A, the opening 420A may be slits in the thin-film sections 216B. Embodiment may include a single slit or multiple slits as illustrated in FIG. 4A. The slits may be used to provide efficient manufacturing of the thin film sections. In another embodiment, as shown in FIG. 4B, the openings 420B may be elliptical in shape. The elliptical shape may be used to allow better flow and/or transmit tension between the top sheet 208 and the bottom sheet 210. The rounded shape may reduce tear or strain points in the thin-film sections 216B. While some of the illustrated

embodiments have utilized rounded shaped openings, embodiments of the invention are not limited to round shapes. Other square, triangle or other polygons may also be used to provide openings for the flow of the culture medium and microorganisms.

[0063] Additional embodiments are not limited to being positioned symmetrically between the top sheet 208 and the bottom sheet 210. As shown in FIG. 4C, the openings 420C can be positioned at the top, bottom, or both in the thin-film section 216B. The openings 420C may include removing material within the thin-film section 216B with a continuous weld along the first edge 222 or second edge 224. In another embodiment, the openings 420C may include removing material on the edge of the thin-film section 216B prior to welding to the top sheet 208 and the bottom sheet 210. Such construction may not include a continuous weld but intermittent weld points between openings 420C.

[0064] In additional embodiments, the successive thin-film sections 216C-D may have alternating locations, for example, thin-film section 216B may have an opening on the bottom and/or to the right while the next successive section 216C may have an opening on the top and/or to the left. Such Embodiment configuration can better provide mixing of the culture medium and microorganisms and/or allow for the distribution of stresses across the photobioreactor.

[0065] Embodiments of the invention may provide a method for supporting pressurized thin-film vessels through the construction of internal thin-film sections 216. In this method, the top sheet 208 and the bottom sheet 210 of thin-film may be sealed together at their edges to form the vessel, while a third, separate sheet of thin-film section 216 may be sealed in between the top sheet 208 and the bottom sheet 210 in order to create an internal wall.

[0066] An exemplary method of sealing thin-film sections 216 may be to fold the thin- film in half around a non heat sealable slip sheet and place this folded sheet in between the top and bottom sheets. When this area is contacted by a heat sealer, each side of the center sheet may be sealed to a different outer layer, while the inside remains unsealed due to the slip sheet. The slip sheet can then be removed, and the remaining edges of the outer two sheets can be sealed together to form the vessel. At this point, when the vessel is pressurized, the thin-film section 216 will stretch perpendicular to the two outer sheets, creating an interior wall.

[0067] Another exemplary method for achieving the thin-film wall is to use a multilayer film that is only heat sealable on one side. In this method, the use of a slip sheet can be avoided, as the film can be folded in a manner that exposes heat sealable film, while having non heat sealable material at the inner walls of the fold. Successive interior sections can also be created by creating a zigzag pattern with the internal film, alternating seals between the top and bottom outer walls.

[0068] Other methods of creating interior thin- film section 216 for thin film inflatable structures exist, as is known in pool floats and inflatable mattresses, however these structures may require more specialized tooling in order to produce the various configurations.

[0069] Referring to FIG. 5 A, each of the thin-film sections 516B-E is coupled to the top sheet 208 at a first edge 516A. The thin-film sections 516B-E may also be coupled to the bottom sheet 210 at a second edge 516A. The width or overlap of the thin-film section material with the top sheet or bottom sheet of the weld may be determined based on the desired stresses seen by the thin-film section 516B-E. Referring to FIG. 5B, an alternative embodiment may incorporate multiple folds of thin-film material to provide the thin-film sections 516B-E. This alternative embodiment can use multiple welds to connect the thin- film section 516B-E to each other and/or the top sheet 208 and bottom sheet 210. In another exemplary construction embodiment the thin-film section 516B-E may be connected at a single point 502 and 504 at the inlet or outlet. The connection may be weld between the various layers or a compression type fitting. The side outer edges (not shown) of each fold may be welded together within the outer edge of the top sheet 208 and bottom sheet 210.

[0070] As shown in FIGS. 6A and 6B, a top profile diagram and a cross-section diagram, respectively, of an illustrative thin-film elongated capsule 602 in accordance with the present invention, according to certain embodiments, are shown. The thin-film elongated capsule 602 includes one or more channels (606A, 606B, 606C, and 606D). The elongated capsule 602 is adapted to allow cultivation in the culture medium of the phototrophic

microorganisms. Phototrophic organisms growing in photobioreactors can be suspended or immobilized. Typically, the channels (606A, 606B, 606C, and 606D) may have a width of about 0.2 cm to 2.5 cm and the top sheet 608 integrated or separate thickness can be about 0.02 cm with a bottom sheet 610 of about 0.2 cm. The layer of culture medium of the phototrophic microorganisms can be between about 5 mm and about 30 mm thick, or, more typically, between about 10 mm and about 15 mm. By inflating the elongated capsule 602 to predetermined amounts with a number of channels across the width of the elongated capsule 602, the desired thickness of the layer of phototrophic microorganisms can be achieved. A substantial even layer can have a thickness with various depths ranging between about 5 mm to about 30 mm thick for a substantial surface area portion of the layer, or, more typically, between about 10 mm to about 15 mm.

[0071] The elongated capsule 602 can be provided by a thin-film material enclosure, typically made from a polymeric material. The phototrophic microorganisms contained in photobioreactors for growth and/or the production of carbon-based products of interest can require light. Therefore, the photobioreactors and, in particular, the elongated capsule 602 are adapted to provide light of a wavelength that is photosynthetically active in the phototrophic microorganism to reach the culture medium.

[0072] The thin-film elongated capsule 602 includes an inlet 604 feeding two or more channels 606A-D and an outlet 605 for receiving the culture medium and microorganisms from the two or more channels 606A-D. Thin-film sections 616 can be positioned between the top sheet 608 and bottom sheet 610 to provide internal walls. The thin-film sections 616 can be bonded along a first edge 622 of the thin-film section to an internal top surface of the top sheet 608. The thin-film sections 616 can also be bonded along a second edge 624 of the thin-film section to an internal bottom surface of the bottom sheet 610 with the second edge being opposite the first edge. The thin-film sections can be distributed along the width of the elongated capsule 602. The edges of the elongated capsule 302 may have the top sheet 608 and bottom sheet 610 bonded along edge seams 612. In another exemplary embodiment, the thin-film sections 616 can be used in place of bonding the top sheet 608 to the bottom sheet 610 giving all channels a more rectangular profile. The seams can be produced using a variety of known heating or welding techniques as described in previous embodiments.

[0073] The thin-film sections 616 can include openings 620 to control the flow through each respective thin-film section 616. The openings 620 can be sized and positioned to allow the flow to be evenly distributed between the multiple channels 606A-D. The distribution can be designed to provide a substantially even distribution between the channels or can be designed to favor circulation to certain channels. A substantially even distribution allows for mixing and even amounts to be dispersed to each of the channels 606A-D. The openings 620 can include a variety of shapes and positioning as described in previous embodiments. [0074] The elongated capsule 602 is not limited to four channels and can have as many or as few as desired according to the intended design constraints of the elongated capsule 602. These design constraints can include, for example, the width of the channel by seams, end region geometry, total width of the reactor chamber, flow characteristics, mechanical stress on the elongated capsule, and/or other characteristics of the elongated capsule 602. The channels 606A-D are also not limited to a straight path as shown in FIGS. 6 A and 26B. The channels 606A-D can be a variety of different shapes and sizes and incorporate openings 620 with a variety of different sizes and positions as described in previous embodiments.

[0075] Hoop stress

[0076] The internal pressure created by the culture medium, microorganisms and gases also induces a hoop stress in the reactor chamber as it is inflated. The hoop stress is calculated by the following equation

[0077] a,, = Pd/2t

[0078] where O_h is the hoop stress, P is the pressure, d is the diameter, and t is the film thickness. By creating thin-film sections 216 decreasing the hoop stress can be provided at the inlet which may experience greater stress relative to the channels 206. This can allow for the use of lower strength; lower cost films or reducing the thickness of the film; higher operating pressures during operation at higher flow rates; aid in mixing, filling, and/or cleaning/sterilizing; and/or reducing the cost. When the culture and gases are introduced into a channeled reactor chamber it is possible the flow is not uniform to all of the channels 206. One method to address this potential problem is to provide thin-film section 216 in combination with various openings 220 at the entrance and exit regions of the elongated capsule 202 to direct flow into each channel 206 as previously discussed. If the flow is not evenly distributed at the entrance to the channels, the thin-film sections 216 and openings 220 can be used to aid in re-distributing the flow further along the length of the elongated capsule 202.

[0079] The channels 206 of the elongated capsule 202 may have a flexible polymer film and having in a plurality of positions distributed along a length of the channel 202, at the inlet 204 or the outlet 205 a reinforced material bonded with the channel 202, the reinforced material surrounding part or the entire perimeter of the channel 202, independently, in the each of the plurality of positions. The reinforced material can be made by overlapping folds of the channel 202 material or different material provided in stripes or hoops that encircle the channels 202 either internal or external to the channels 202. [0080] As shown in FIG. 7, a perspective view of an illustrative thin-film reactor chamber 402 in accordance with the present invention, according to certain embodiments, is shown. The elongated capsule 702 includes channels 706 coupled to an entrance port 716 and an exit port 718. The entrance port 716 includes a distribution region that couples to each channel of the reactor chamber 702. Embodiments of the invention can be used to provide a reactor with the distribution region incorporated into the thin- film reactor chamber as previously described in prior embodiments. Rigid plates 720 may be used above and below the distribution regions to reduce stress at the inlet according to some embodiment.

However, embodiments may allow for designs of thin- film reactor that does not require or reduces the additional support required of the rigid plates 720.

[0081] FIG. 8 is a schematic top profile of an exemplary elongated capsule 802 of a photobioreactor of the present invention (the outflow region of the elongated capsule is not shown and only part of the channeled area is shown, similarily to the aforegoing described figures). Channels 806 of the elongated capsule are provided by bonding a top sheet of the flexible enclosure of the capsule with an bottom sheet of the flexible enclosure to form bonded areas or lines 808 (e.g., seams or welds). It has been found that areas that are particularly prone to potential damage, particularly, at high operating pressures, are those where bonded areas (e.g., seams or welds) begin, for example, those areas indicated by 810. Stress on these areas can be reduced by adjacent placement of at least one flexible polymer section 316 of the present invention. As described in the foregoing the flexible polymer section can be designed in various ways, for example, as shown in FIGS. 2C-2E and 4A-4C. The flexible enclosure of the capsule and the flexible polymer section jointly define a thin- film header volume 810 which is directly connected to the inlet 805. The shape of the thin- film header volume is not limited to the one shown in FIG. 8. Typically, the angle 815 between the inflow direction and the length direction of the elongated capsule is equal to or smaller than 90°.

[0082] Exemplary Dimensions

[0083] An exemplary elongated capsule setup of a structure shown in Figs. 6A and 6B may have total width of about 196 mm with channels of about 50 mm and served with an inlet of about 152.4 mm. These dimensions are prior to inflation and measured with the thin- film reactor is lying flat. Given these dimensions an optimal thin-film section or internal wall may have a height of about 25.4 mm. This may provide a balance between a shorter thin-film section height increasing pressure at seam ends (decreasing the peel angle) and to high of strain on the thin-film sections. Embodiments are not limited to these dimensions. In addition, other embodiments may use dimensions that are proportional to these specific setup dimensions.

[0084] In another setup, the internal sections may have internal walls of 1 inch strips spaced 0.9 inches apart. The exemplary setup may have a flow area: 81.22 in², a pressure drop:0.066 PSI, and a max misdistribution of 13%. In another setup, the internal sections may have internal walls with elliptical openings having 3.310 inch and 1.150 inch diameters, spaced 3.865 inches apart on center. The exemplary setup may have a flow area: 62.82 in , a pressure drop:0.093 PSI, and a max misdistribution of 16%. In another setup, the internal sections may have internal walls with circular openings having 0.750 inch diameter, spaced 2 inches apart on center and 1 inch above and below on center. The exemplary setup may have a flow area: 57 in²a pressure drop:0.071 PSI, and a max misdistribution of 12%. In another setup, the internal sections may have internal walls with circular openings having 0.5 inch diameter, spaced 2 inches apart on center and 1 inch above and below on center. The exemplary setup may have a flow area: 23.7 in², a pressure drop:0.123 PSI, and a max misdistribution of 33%. Embodiments are not limited to these dimensions. Air only burst pressuring testing of an exemplary elongated capsule may have a burst pressure of 4.89 PSI for an elongated capsule with a header, 8.86-917 PSI for an elongated capsule with a full length short transition, and 10.81 PSI for elongated capsule with a full length and internal section transition. In addition, other embodiments may use dimensions that are proportional to these specific setup dimensions.

[0085] Photobioreactor Biomass Productivity

[0086] The solar biofactory also provides methods to achieve organism productivity as measured by production of desired products, which includes cells themselves.

[0087] The desired level of products produced from the engineered light capturing organisms in the solar biofactory system can be of commercial utility. For example, the engineered light capturing organisms in the solar biofactory system convert light, water and carbon dioxide to produce fuels, biofuels, biomass or chemicals at about 5 to about

10g/m2/day, in certain embodiments about 15 to about 42g/m²/day and in more preferred embodiments, about 30 to 45g/m²/day or greater.

[0088] The photobioreactor system affords high areal productivities that offset associated capital cost. Superior areal productivities are achieved by: optimizing cell culture density through control of growth environment, optimizing C0₂ infusion rate and mass transfer, optimizing mixing to achieve highest photosynthetic efficiency/organisms, achieving maximum extinction of insulating light via organism absorption, and achieving maximum extinction of C0₂ and initial product separation.

[0089] In particular, the southwestern U.S. has sufficient solar insulation to drive maximum areal productivities to achieve about >25,000 gal/acre/year ethanol or about> 15,000 gal/acre/year diesel, although a majority of the U.S. has insulation rates amenable to cost effective production of commodity fuels or high value chemicals.

[0090] Furthermore, C0₂ is also readily available in the southwestern U.S. region, which is calculated to support large scale commercial deployment of the invention to produce 25 - 70 g/m²/day ethanol, or 70 Bn gal/year diesel.

[0091] Definitions

[0092] Suitable phototrophic microorganisms can produce a carbon-based product and/or the phototrophic microorganism itself can be processed as feed stock for the production of a carbon-based product. Particularly suitable phototrophic microorganisms can be genetically engineered to produce a desired carbon-based product. Exemplary suitable phototrophic microorganisms are described in U.S. Patent No. 7,919,303, U.S. Patent No. 7,794,969, U.S. Patent Application No. 12/833,821, U.S. Patent Application No. 13/054,470, U.S. Patent Application No. 12/867,732, WO/2009/1 11513, WO/2009/036095, WO/2011/005548, WO/2011/006137 and WO/2011/011464.

[0093] "Carbon-based products of interest" include alcohols such as ethanol, propanol, isopropanol, butanol, fatty alcohols, fatty acid esters, ethyl esters, wax esters; hydrocarbons and alkanes such as pentadecane, heptadecane, propane, octane, diesel, Jet Propellant 8 (JP8); polymers such as terephthalate, 1 ,3 -propanediol, 1 ,4-butanediol, polyols,

Polyhydroxyalkanoates (PHA), poly-beta-hydroxybutyrate (PHB), acrylate, adipic acid, ε- caprolactone, isoprene, caprolactam, rubber; commodity chemicals such as lactate, docosahexaenoic acid (DHA), 3-hydroxypropionate, γ-valerolactone, lysine, serine, aspartate, aspartic acid, sorbitol, ascorbate, ascorbic acid, isopentenol, lanosterol, omega-3 DHA, lycopene, itaconate, 1,3 -butadiene, ethylene, propylene, succinate, citrate, citric acid, glutamate, malate, 3-hydroxypropionic acid (HPA), lactic acid, THF, gamma butyrolactone, pyrrolidones, hydroxybutyrate, glutamic acid, levulinic acid, acrylic acid, malonic acid;

specialty chemicals such as carotenoids, isoprenoids, itaconic acid; pharmaceuticals and pharmaceutical intermediates such as 7-aminodeacetoxycephalosporanic acid (7- ADCA)/cephalosporin, erythromycin, polyketides, statins, paclitaxel, docetaxel, terpenes, peptides, steroids, omega fatty acids and other such suitable products of interest. Such products are useful in the context of bio fuels, industrial and specialty chemicals, as intermediates used to make additional products, such as nutritional supplements,

neutraceuticals, polymers, paraffin replacements, personal care products and pharmaceuticals. More typical carbon-based products are fuels (e.g. alcohols or alkanes). Even more typically, carbon-based products are ethanol, propanol, isopropanol, butanol, terpenes, alkanes such as pentadecane, heptadecane, octane, propane, fatty acids, fatty esters, fatty alcohols, olefins or diesel.

[0094] As used herein, "light of a wavelength that is photosynthetically active in the phototrophic microorganism" refers to light that can be utilitzed by the microorganism to grow and/or produce carbon-based products of interest, for example, fuels including biofuels.

[0095] As used herein, "transparent" refers to an optical property that allows passage of light of a wavelength that is photosynthetically active in the phototrophic microorganism and or other desirable wavelengths of light.

[0096] As used herein, "flexible wall" refers to a sheet or sheets of material that have the ability to flex or bend under a relative force or pressure is applied to a surface during operation.

[0097] As used herein, "thin- film" refers to a flexible film, for example, a polymer or polymer composite film. Thickness of the film or sheet can be less than 500 micrometers, preferable from 100 to 200 micrometers.

[0098] "Phototrophs" or "photoautotrophs" are organisms that carry out photosynthesis such as, eukaryotic plants, algae, protists and prokaryotic cyanobacteria, green- sulfur bacteria, green non-sulfur bacteria, purple sulfur bacteria, and purple non-sulfur bacteria. Phototrophs include natural and engineered organisms that carry out photosynthesis and hyperlight capturing organisms.

[0099] The photobioreactors of the present invention are adapted to support a biologically active environment that allows chemical processes involving photosynthesis in organisms such as phototrophic organisms to be carried out, or biochemically active substances to be derived from such organisms. The photobioreactors can support aerobic or anaerobic organisms.

[00100] As used herein, "organisms" encompasses autotrophs, phototrophs, heterotrophs, engineered light capturing organisms and at the cellular level, e.g., unicellular and

multicellular. [00101] A "spectrum of electromagnetic radiation" as used herein, refers to electromagnetic radiation of a plurality of wavelengths, typically including wavelengths in the infrared, visible and/or ultraviolet light. The electromagnetic radiation spectrum is provided by an electromagnetic radiation source that provides suitable energy within the ultraviolet, visible, and infrared, typically, the sun.

[00102] A "biosynthetic pathway" or "metabolic pathway" refers to a set of anabolic or catabolic biochemical reactions for converting (transmuting) one chemical species into another. For example, a hydrocarbon biosynthetic pathway refers to the set of biochemical reactions that convert inputs and/or metabolites to hydrocarbon product-like intermediates and then to hydrocarbons or hydrocarbon products.

[00103] Anabolic pathways involve constructing a larger molecule from smaller molecules, a process requiring energy. Catabolic pathways involve breaking down of larger molecules, often releasing energy.

[00104] As used herein, "light" generally refers to sunlight but can be solar or from artificial sources including incandescent lights, LEDs fiber optics, metal halide, neon, halogen and fluorescent lights.

[00105] Throughout this specification and claims, the word "comprise" or variations such as "comprises" or "comprising," will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[00106] The foregoing description, for purposes of explanation, used specific

nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of this invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. These procedures will enable others, skilled in the art, to best utilize the invention and various embodiments with various modifications. It is intended that the scope of the invention be defined by the following claims and their equivalents. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims. [00107] While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims

CLAIMS The invention claimed is:

1. A photobioreactor for a phototrophic microorganism and culture medium therefor, comprising an elongated capsule comprised of a flexible polymer film which is at least partially transparent to light of a wavelength that is photosynthetically active in the phototrophic microorganism, wherein the flexible polymer film provides a flexible enclosure having an internal top surface and an internal bottom surface of the elongated capsule; the elongated capsule further comprising

(a) an inlet for flowing culture medium into the elongated capsule;

(b) an outlet for flowing culture medium out off the elongated capsule; and

(c) a plurality of flexible polymer film sections within the elongated capsule;

(i) each flexible polymer film section bonded along a first edge of the flexible polymer film section to the internal top surface and along a second edge of the flexible polymer film section, which is opposite to the first edge, to the internal bottom surface;

(ii) each flexible polymer film section, independently, having a plurality of openings;

(iii) each flexible polymer film section being dimensioned to constrain the inflatable volume of the flexible enclosure; and

(iv) the plurality of flexible polymer film sections being in positions distributed along a length of the elongated capsule.

2. The photobioreactor of Claim 1, wherein the flexible polymer film sections are distributed along the entire length of the capsule.

3. The photobioreactor of Claims 1 or 2, wherein the elongated capsule is a capsule without a plurality of adjacent channels.

4. The photobioreactor of Claim 1 or 2, wherein the elongated capsule has a first region extending from an inlet to a second region, wherein the elongated capsule is divided widthwise into a plurality of adjacent channels in the second region, each channel being comprised of the flexible polymer film.

5. The photobioreactor of Claim 4, wherein the plurality of flexible polymer film sections is positioned in the first region.

6. The photobioreactor of any one of Claims 1 to 5, wherein at least one of the plurality of flexible polymer film sections is oriented along the width of the capsule.

7. The photobioreactor of any one of Claims 1 to 6, wherein at least one of the plurality of flexible polymer film sections extends across the width of the capsule.

8. The photobioreactor of any one of Claims 1 to 7, wherein flexible polymer film sections of the plurality of flexible polymer film sections have different numbers of openings.

9. The photobioreactor of any one of Claims 1 to 8, wherein the openings of the flexible polymer film sections increase in number from a first of the plurality of polymer film sections closest to the inlet to a second of the plurality of polymer film sections.

10. The photobioreactor of any one of Claims 1 to 9, wherein the openings have an average size smaller than the inlet.

1 1. The photobioreactor of any one of Claims 1 to 10, wherein the average distance of adjacent polymer film sections of the plurality of polymer film sections is uniform along the length of the capsule from the inlet towards the outlet.

12. The photobioreactor of any one of Claims 1 to 11, wherein the average distance of adjacent polymer film sections of the plurality of polymer film sections increases along the length of the capsule from the inlet towards the outlet.

13. The photobioreactor of any one of Claims 1 to 12, wherein at least one of the plurality of polymer film sections is bonded along its entire perimeter to an inside surface of the flexible enclosure.

14. The photobioreactor of any one of Claims 1 to 12, wherein at least one of the plurality of polymer film sections is only bonded along part of its entire perimeter to an inside surface of the flexible enclosure.

15. The photobioreactor of any one of Claims 1 to 12, and 14, wherein at least two of the plurality of polymer film sections are oriented along the width of the capsule, and positioned side by side, jointly spanning part or the entire width of the capsule.

16. The photobioreactor of Claim 15, wherein the at least two of the plurality of polymer film sections are positioned to provide gaps between the two polymer film sections.

17. A photobioreactor for a phototrophic microorganism and culture medium therefor, comprising an elongated capsule comprised of a flexible polymer film that is at least partially transparent to light of a wavelength that is photosynthetically active in a phototrophic microorganism, wherein the elongated capsule is divided widthwise into a plurality of adjacent channels, each channel being comprised of the flexible polymer film and having in a plurality of positions distributed along a length of the channel a reinforced material bonded with the channel, the reinforced material surrounding part or the entire perimeter of the channel, independently, in the each of the plurality of positions.

18. A photobioreactor for a photo trophic microorganism and culture medium therefor, comprising an elongated capsule comprised of a flexible polymer film which is at least partially transparent to light of a wavelength that is photo synthetically active in the phototrophic microorganism, wherein the flexible polymer film provides a flexible enclosure having an internal top surface and an internal bottom surface of the elongated capsule; the elongated capsule further comprising

(a) an inlet for flowing culture medium into the elongated capsule;

(b) an outlet for flowing culture medium out off the elongated capsule; and

(c) a flexible polymer film sections within the elongated capsule;

(i) the flexible polymer film section bonded along a first edge of the flexible polymer film section to the internal top surface and along a second edge of the flexible polymer film section, which is opposite to the first edge, to the internal bottom surface;

(ii) the flexible polymer film section, independently, having a plurality of openings;

(iii) the flexible polymer film section being dimensioned to constrain the inflatable volume of the flexible enclosure; and

(iv) the flexible polymer film section being positioned adjacent to the inlet.

19. The photobioreactor of any one of Claim 18, wherein the elongated capsule has a first region extending from an inlet to a second region, wherein the elongated capsule is divided widthwise into a plurality of adjacent channels in the second region, each channel being comprised of the flexible polymer film.

20. The photobioreactor of Claim 19, wherein the flexible polymer film section is positioned in the first region.

21. The photobioreactor of any one of Claims 18 to 20, wherein the flexible polymer film sections is oriented to span along a width of the capsule.

22. The photobioreactor of any one of the preceding claims, wherein the capsule provides a thin-film header volume formed at one end of the capsule which is directly connected to the inlet to receive flow of culture medium, the flexible polymer film section geometrically separating the volume of the thin-film header volume from the remaining volume of the capsule, and the plurality of openings of the flexible polymer film section providing openings for culture medium to flow from the thin-film header volume into the remaining volme of the capsule.

23. The photobioreactor of any one of the preceding claims, wherein the inlet is positioned in a corner of the capsule.

24. The photobioreactor of any one of the preceding claims, the cross-sectional area of the thin-film header volume decreases from the inlet towards an end opposite to the inlet.

25. The photobioreactor of any one of the preceding claims, wherein the angle between an inflow direction provided by the inlet and the length direction of the capsule is equal to or smaller than 90°.

26. The photobioreactor of any one of the preceding claims, wherein the angle is between 35° and 80°.

27. The photobioreactor of any one of the preceding claims, wherein each flexible polymer section is dimensioned to constrain the inflatable volume of the flexible enclosure by having a length between points along the first and second edge of the flexible polymer section connecting points of the internal top surface and internal bottom surface of the elongated capsule, which is shorter than a respective length between the points of the internal top surface and internal bottom surface that would be measured in the absence of the polymer film section when the capsule is fully inflated.