Flow control tray for algae culture fluid, algae culture system, and use of the algae culture system

Abstract

1. A flow control tray for algal culture fluid, comprising: a grounding layer extending along a grounding surface from a first end to a second end; and a plurality of ridges extending in a first direction from the grounding layer, wherein the grounding layer is configured to guide the flow of the algal culture fluid on the grounding surface from the first end to the second end, forming a general flow direction parallel to the grounding layer; each of the plurality of ridges is spaced apart in a direction perpendicular to the grounding surface and comprises a support configured to support an algal culture membrane; and each of the plurality of ridges preferably has a three-dimensional shape configured to divert the culture fluid from the general flow direction.

Description

[Technical Field]

[0001] The present invention relates to a flow control tray for algae culture fluid, an algae culture system comprising a flow control tray and an algae culture layer, and uses of the algae culture system. [Background technology]

[0002] The latest technology is already known to produce the carotenoid astaxanthin from microalgae such as Haematococcus pluvialis using porous substrate bioreactors (PSBRs). In PSBRs, the algae are cultivated in a biofilm on a wet surface with a very low water content in the culture medium.

[0003] According to the current state of the art, PSBRs are used in combination with prefabricated greenhouse equipment, where trays are used to control the distribution of culture fluids, such as nutrient media, within the greenhouse bench system.

[0004] According to the latest technology in microalgae production, astaxanthin-containing microalgae, such as Haematococcus, are produced on a top culture membrane (also called the microalgae culture layer) of a PSBR, which is permeable to water and nutrients, such as the algae culture fluid. Meanwhile, the membrane prevents the algae from floating in the bulk of the aqueous algae culture fluid (= nutrient solution), which is formed from water and nutrients. The algae culture fluid is supplied from the bottom side of the membrane by continuously circulating the culture fluid along the bottom of the membrane. Such continuous circulation of the culture fluid can be established, for example, in a standard greenhouse bench, which is equipped with a liquid tank, the top of which is supplied with the culture fluid and the bottom of which is discharged.

[0005] According to the latest technology, production setups for microalgae cultivation utilize standard inclined greenhouse bench systems, which are combined with vacuum-formed plastic trays for water and nutrient distribution. To cultivate microalgae, standard greenhouse benches are provided with hydrophilic sheet-like algae culture layers. Other types of inclined greenhouse bench systems suitable for water and nutrient distribution can also be used, apart from the standard mentioned above.

[0006] According to the latest technology, a microalgae culture layer is formed by a sheet-like composite layer consisting of at least two functional units: a thin microporous membrane that serves as the upper microalgae culture layer, and at least one lower distribution layer, for example made of a bulky polyester fiber nonwoven fabric, that distributes the nutrient medium from the water nutrient supply structure in the lower layer to the membrane. According to the latest technology, it is also known to use paper sheets, carpets, gauze, glass fibers, sponges, etc. for culturing microalgae in PSBRs.

[0007] The above-mentioned state-of-the-art algae cultivation methods and systems have the following drawbacks:

[0008] 1. A distribution layer is required to support the microporous membrane, which increases the manufacturing complexity and material demands of the sheet-like composite layer.

[0009] 2. In the current state of the art, it is known to use distribution layers such as paper sheets, carpets, gauze, glass fibers, sponges, etc. for culturing microalgae in PSBRs. The aforementioned materials have the common drawback of providing a small / limited space for the distribution layer, which creates a large resistance to the flow of the supplied algae culture fluid. This results in the limited amount of culture fluid (15 Lm) per time interval. -1 h -1 Less than 5Lm -1 h -1Therefore, only a small amount (less than 100%) of fresh culture fluid is supplied to the bioreactor, and the growth rate of the microalgae is limited by the amount of fresh culture fluid supplied, which in turn depends on the flow rate of the culture fluid. This occurs especially when long flow channels on long benches / trays are used, which can gradually limit the productivity of the culture along the flow direction.

[0010] 3. Furthermore, due to the low flow rate and narrow space, the distribution layer is prone to biofouling, clogging the layer structure and causing flow disturbances, which can result in partial or complete interruption of the cultivation process.

[0011] 4. Furthermore, during the cultivation process, gases released from the culture medium and from algae photosynthesis accumulate between the microporous membrane and the distribution layer, which separates the membrane carrying the microalgae from the distribution layer. As a result, the gas layer cuts off the supply of water and nutrients to the microalgae, damaging the culture medium in the separated area, especially due to drying.

[0012] 5. In some configurations, laminar flow can occur, leading to adverse mixing of the culture medium and reduced mass transfer across the membrane. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention aims to solve the aforementioned problems and drawbacks of known algae-related technologies, such as microalgae cultivation methods and systems. Specifically, the present invention aims to provide improved methods and systems that allow for faster microalgae growth and a more stable process, while at the same time simplifying the design and using fewer parts. [Means for solving the problem]

[0014] The above object is achieved by the independent claims of the present invention.

[0015] According to a first aspect of the present invention, there is provided a flow control tray for algae cultivation, such as the cultivation of microalgae. The flow control tray according to the present invention comprises a grounding layer extending along a grounding surface from a first end to a second end, and a plurality of ridges extending in a first direction from the grounding layer. The grounding layer is configured to guide a flow of an algae cultivation fluid, such as a nutrient medium, above the grounding surface from the first end to the second end, forming a general flow of the cultivation fluid parallel to and above the grounding layer.

[0016] The flow of the algae culture above the ground layer can be a continuous flow of culture fluid. Alternatively, according to the present invention, the algae culture fluid can be provided as a discontinuous flow, with the culture fluid being provided to the flow control tray at timed intervals.

[0017] The ground surface may be arranged in a plane inclined relative to the horizontal, with the first end of the ground layer of the flow control tray being positioned higher than the second end. The horizontal plane is defined as extending in a plane perpendicular to the vector of gravity. By slanting the ground layer of the flow control layer, the culture fluid supplied to the first end region of the flow control tray forms a fluid flow under the action of gravity, with the general flow direction being toward the second end of the control tray above the ground layer of the flow control tray.

[0018] The contact surface according to the present invention can be formed with a thickness that varies generally along the flow direction, providing a sloped contact surface.

[0019] The ground layer has two opposing lateral sides formed by the first end and the second end, and two opposing longitudinal sides extending generally along the flow direction. The area of ​​the ground layer may be defined as the area enclosed by the lateral and longitudinal sides. The ground layer may be rectangular or quadratic in shape.

[0020] Each of the plurality of ridges comprises a support portion spaced apart in a direction perpendicular to the ground surface and configured to support the algae culture membrane. Each of the plurality of ridges is provided with a three-dimensional geometric shape / form. The geometric shape / form may be configured to deflect the culture fluid from the general flow direction.

[0021] Optionally, each of the plurality of ridges has a three-dimensional shape that induces a laminar vortex in the culture fluid with a horizontal axis of rotation.

[0022] Preferably, the support portion of each of the plurality of protuberances is disposed in a second support surface that extends parallel to the ground surface and is spaced a support height from the ground surface.

[0023] Alternatively, the present invention may provide that the plurality of protuberances are arranged on at least two different support surfaces, the support portions being arranged at positions spaced apart from the ground surface by at least two different support heights.

[0024] Preferably, the area of ​​the second support surface is as small as possible to allow optimal transfer of culture medium through the culture membrane.

[0025] The plurality of ridges may have a three-dimensional shape selected as one or more members of the following list: cylinder, rectangle, pyramid or cone, hemisphere, hemidroplet. The three-dimensional shape may be inclined with respect to the ground plane.

[0026] Optionally, each ridge is formed as a ramp extending in a first direction from the ground plane to the upper support at a first support height, the ramp shape may be, for example, rectangular, quadratic, trapezoidal, circular, etc.

[0027] The support for the membrane by each ridge is formed by an upper support surface or an upper support edge, or alternatively by an upper support point.

[0028] The raised portion is preferably formed as a triangular inclined portion extending generally along the flow direction from a triangular base located on the ground surface to a support portion spaced apart in a first direction from the ground surface, and the width of the triangular inclined portion narrows generally in the flow direction.

[0029] Optionally, the triangular ramp is provided with a triangular tip as a support, or is formed as a truncated triangle with a triangular edge as a support. Alternatively, the triangular ramp may be provided with an upper support surface.

[0030] The ridges may be evenly distributed over an area of ​​the ground layer, or alternatively, may be randomly / irregularly positioned over an area of ​​the ground layer.

[0031] Preferably, the ridges are arranged in a plurality of rows, the rows being generally perpendicular to the flow direction, the rows being evenly distributed along the general flow direction and spaced apart by a row spacing.

[0032] Furthermore, the ridges arranged in a row may be spaced apart from one another in the direction of the row by a gap spacing between adjacent ridges.

[0033] Further, according to the present invention, in two consecutive rows of ridges as viewed in the general flow direction, the pattern of ridges in adjacent rows can be offset by a first offset distance, such that the ridges of the second row following the first row in the general flow direction are located in the gap areas of the ridges of the first row, thereby providing an alternating pattern of ridge rows across the entire area of ​​the ground contact patch in the general flow direction.

[0034] With the above configuration, the culture fluid flowing through the first row of ridges, specifically the gap regions between the ridges in the first row, then moves to the second row in an alternating pattern in the general flow direction, with the flow regions flowing through the gap regions being directed towards the ridges in the second row, thereby branching, resulting in a continuously branching culture fluid due to the alternating ridge pattern provided with successive rows of ridges seen in the general flow direction.

[0035] Furthermore, according to the present invention, the continuous flow of algae culture fluid can be configured to form a continuous liquid film having a fluid layer height above the ground layer in a first direction.

[0036] Preferably, the height of the fluid layer in a direction perpendicular to the ground plane is equal to the support height of the ridge in the same direction.

[0037] The plurality of ridges may be spaced apart in a direction parallel to the ground surface by a minimum spacing in the range of 0.1 cm to 10.0 cm.

[0038] Further, in accordance with the present invention, the ground layer and the plurality of ridges may be manufactured from a continuous sheet of material by a vacuum forming process.

[0039] According to the present invention, the grounding layer can be formed from a single metal plate, and the ridges can be embossed or stamped from the metal plate. The grounding layer can also be manufactured by CNC milling, 3D printing, hydroforming, stamping, cutting, or a combination of these manufacturing processes. The ridges can be manufactured separately, for example, by 3D printing or injection molding, and then mechanically or chemically bonded to the grounding layer.

[0040] In an alternative configuration of the invention, the ground layer is formed by a plurality of trusses or structures extending into the ground plane between the plurality of ridges and connected to the plurality of ridges to form a mesh-like structure between the plurality of ridges, the mesh-like structure extending into the ground plane with different or no material between the ridges and the plurality of trusses. The plurality of trusses may also be of different thicknesses to create a slope in the ground plane.

[0041] The tray and ridge materials may be plastic or metal that meets the requirements of being "waterproof," inert, and non-toxic. Non-waterproof and / or reactive materials may also be coated with an appropriate coating that meets these requirements.

[0042] The ground layer may be formed as a continuous ground wall, or alternatively, may be formed as a perforated plate or mesh-like structure.

[0043] The ground layer may further be provided with at least one side wall extending in the first direction to laterally separate the ground layer to form tabs. Preferably, the ground layer has a side wall on each lateral side and longitudinal side, forming a circumferential wall such that the ground layer forms a tab.

[0044] The bending stiffness of the ground layer can be increased by forming a plurality of ribs on the ground layer. The ribs may be arranged parallel to the longitudinal and / or lateral sides of the ground layer. The ribs may be formed to extend generally along the flow direction.

[0045] More preferably, the plurality of ribs may extend in the first direction to an extended height that is less than the first support height.

[0046] The second end of the tray may be modified to optimize the outflow of nutrient solution into the drainage system.

[0047] According to a second aspect, the present invention provides an algae cultivation system comprising a flow control tray according to the first aspect of the present invention, and further comprising an algae cultivation layer.

[0048] The algae culture layer may be formed from a mineral or a hydrophilic organic material, or a combination thereof, specifically, from at least one member selected from the list of organic materials such as paper, cellulose ester, cellulose acetate, mixed cellulose ester, cellulose, cellulose nitrate, polyamide, polyester, polyolefin, and / or graphene.

[0049] Alternatively or additionally, the culture membrane may comprise at least one inorganic material selected from the list of porous ceramic materials and / or glass fibers.

[0050] The algae culture layer may be formed by a fluid-permeable membrane.

[0051] The algae culture layer may be formed by a hydrophilic culture membrane with a pore size of less than 50 μm. More preferably, the pore size of the culture layer is in the range of 0.1 μm to 25 μm. In specific examples of the present invention, medium pore sizes of 10 μm, 8.0 μm, 7.5 μm, 5.0 μm, 1.2 μm, 0.4 μm, and 0.1 μm were used.

[0052] The algae culture layer may further be formed by an algae culture membrane having a thickness of less than 50 μm and / or a pore size of less than 25 μm, preferably made of polybutylene terephthalate.

[0053] The system may further include a liquid supply unit disposed in the region of the first end of the grounding layer and configured to uniformly supply the incoming algae culture fluid to the first end of the grounding layer. The liquid supply unit may provide benefits such as improving the inflow of the culture fluid from the supply pipe, such as avoiding the generation of bubbles and spills.

[0054] According to a third aspect, the present invention provides the use of an algal cultivation system according to the second aspect of the invention for culturing microalgae, in particular astaxanthin-containing microalgae.

[0055] The following exemplary embodiments are described in accordance with the present invention with reference to the accompanying drawings. [Brief explanation of the drawings]

[0056] [Figure 1A] FIG. 1 is a schematic perspective view of a first exemplary embodiment of a flow control tray. [Figure 1B] FIG. 10 illustrates a second exemplary embodiment of a flow control tray. [Figure 1C] FIG. 10 illustrates a third exemplary embodiment of a flow control tray according to the present invention. [Figures 2A-2C] 1A-1C illustrate three different exemplary embodiments of ridges on a flow control tray according to the present invention. [Figure 3] 10A-10C are cross-sectional views of further exemplary embodiments of flow control trays according to the present invention. [Figure 4] FIG. 10 is a further perspective view of an exemplary flow control tray, where the tray is formed as a tab. [Figure 5] 10A-10C show examples of ridge patterns for flow control trays according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0057] 1A shows a perspective view of a first exemplary embodiment of a flow control tray 1 according to the present invention. The flow control tray 1 for algae cultivation comprises a ground layer 11 extending along a ground surface from a first end 13 to a second end 15. The ground layer 11 in FIG. 1A is formed by a continuous flat sheet material, with a plurality of ridges 12 extending from said ground layer 11 in a first direction 14.

[0058] The grounding layer 11 is configured to guide the flow of the algae culture fluid over the grounding surface from the first end 13 to the second end 15, forming a general flow direction 100. The general flow direction is indicated in FIG. 1A by arrow 100 parallel to the grounding layer 11. Each of the plurality of ridges 12 is spaced apart in a direction perpendicular to the grounding surface and includes a support portion 121 configured to support the algae culture membrane 2 (not shown in FIG. 1). The support portion 121 in FIG. 1A is formed as an upper support edge 121B. As can be seen in FIG. 1A, each of the plurality of ridges 12 has a three-dimensional shape and is configured to divert the culture fluid from the general flow direction 100.

[0059] Each of the plurality of ridges 12 has a three-dimensional shape for inducing laminar vortices having horizontal rotational axes in the culture fluid. Specifically, in the exemplary embodiment of FIG. 1A , each ridge 12 is formed as a slope extending from the ground surface 11 in a first direction 14 to an upper support 121 at a first support height h. Each of the illustrated ridges 12 is formed as a triangular slope extending from a triangular base 122 at the ground surface to the support 121 spaced from the ground surface in the first direction 14 generally along the flow direction 100, with the width of the triangular slope narrowing along the flow direction 100.

[0060] 1B illustrates a second exemplary embodiment of a flow control tray 1 according to the present invention. The embodiment illustrated in FIG. 1B differs from the configuration illustrated in FIG. 1A in that the grounding layer 11 extending along the grounding surface from the first end 13 to the second end 15 is formed by the wedge-shaped portion itself, and the grounding layer 11 is inclined relative to the support surface, which increases the distance between the first end 13 and the second end 15 relative to the support surface. Due to this inclination, the culture fluid placed on the flow control tray 1 in the region of the first end 13 flows to the second end 15 of the flow control tray 1 under the existing gravity.

[0061] 1C illustrates yet a third exemplary embodiment of a flow control tray 1, which differs from the embodiment of FIGS. 1A and 1B in the configuration of the ground layer 11. Specifically, the ground layer 11 of the flow control tray 1 of FIG. 1C is formed by a plurality of connectors / trusses that connect a plurality of ridges 12 to one another. As a result, the flow control tray 1 of FIG. 1C, specifically the ground layer 11, is formed as a mesh-like structure, with ridges 12 disposed at the intersections of the mesh-like structure to form the flow control tray 1.

[0062] 2A to 2C show three different exemplary embodiments of the raised portion 12 of the flow control tray 1. Each raised portion 12 in FIG. 2 is formed as a slope extending from the ground surface 11 in a first direction to an upper support portion 121 at a first support height h. The configurations of the raised portions 12 in FIG. 2 differ in the configuration of the upper support portion 121. Specifically, FIG. 2A shows a configuration in which an upper support point 121A is formed. The raised portion 12 in FIG. 1A is formed as a triangular slope extending along the general flow direction 100 from a triangular base 122 at the ground surface to a support portion 121 spaced apart from the ground surface in a first direction 14. The triangular slope narrows in the general flow direction. According to FIG. 2A, the triangular slope is provided with a triangular tip 121A as the support portion 121. In Figure 2B, the triangular ramp is formed as a truncated triangle with triangular edge 121B as upper support 121. In Figure 2C, the ramp is formed as upper support surface 121C.

[0063] FIG. 3 shows a cross-sectional view of an exemplary embodiment of a flow control tray according to the present invention, in which a plurality of ridges 12 extending from a ground layer 11 formed at equal heights are formed in the control tray, and it can be seen that the plurality of ridges 12 extend from said ground layer 11 in a first direction 14. The plurality of ridges 12 extend from a triangular base 122 of the ground surface 11 in the first direction 14 to a support 121 away from the ground surface. The upper support 121 is positioned at a first support height h above / away from the ground surface 11. Additionally, FIG. 3 shows an algae culture membrane 2, which is supported by the plurality of supports 121 of the ridges 12.

[0064] FIG. 4 shows a further exemplary embodiment of a flow control tray 1 in which the ground layer 11 is formed with side walls to form tab-like ground layer 11 .

[0065] 5 illustrates a plurality of ridges 12 arranged in a plurality of rows 120, the rows 120 extending perpendicular to the general flow direction 100, the rows 120 evenly distributed along the general flow direction 100, and spaced apart by a matrix spacing D. The plurality of ridges 12 arranged in the rows 120 are spaced apart from one another along the rows 120 by a gap spacing C. As can be seen from FIG. 5, the row patterns of the plurality of ridges 12 in two consecutive rows 120 viewed in the general flow direction 100 are offset from one another to form an alternating structure of the plurality of ridges 12. The row patterns are offset in a direction perpendicular to the general flow direction 100.

Claims

1. A flow control tray (1) for algae culture fluid, comprising: a ground layer (11) extending along the ground plane from a first end (13) to a second end (15); a plurality of ridges (12) extending from the ground layer (11) in a first direction (14); Equipped with the ground layer (11) is configured to guide the flow of algae culture fluid on the ground surface from the first end (13) to the second end (15), forming a flow direction (100) generally parallel to the ground layer; Each of the plurality of protrusions (12) is provided at a distance from each other in a direction perpendicular to the ground surface, and includes a support (121) configured to support an algae culture membrane (2); Each of the plurality of ridges (12) preferably has a three-dimensional shape configured to divert the culture fluid from the general flow direction (100). Flow control tray for algae culture fluid (1).

2. 2. The tray (1) of claim 1, wherein each of the plurality of ridges (12) has a three-dimensional shape for inducing a laminar vortex having a horizontal axis of rotation in the culture fluid.

3. 3. The tray (1) according to claim 1 or 2, wherein each support portion (121) of the plurality of ridges (12) is arranged in a second support plane parallel to the ground plane.

4. 4. The tray (1) according to claim 1, wherein each of the raised portions (12) is formed as a slope extending along the first direction (14) from the ground surface (11) to the upper support (121) at a first support height (h).

5. The support portion (121) of each protuberance (12) is Upper support surface (121C), an upper support edge (121B), or A tray (1) according to any one of claims 1 to 4, formed by an upper support point (121A).

6. 6. The tray (1) according to claim 1, wherein the raised portion (12) is formed as a triangular inclined portion extending in the general flow direction (100) from a triangular base (122) on the contact surface to the support portion (121) spaced apart in the first direction (14) relative to the contact surface, and the width of the triangular inclined portion narrows along the general flow direction (100).

7. 7. The tray (1) according to claim 6, wherein the triangular inclined portion is provided with a triangular tip (121A) as a support portion (121) for the membrane (2), or the triangular inclined portion is formed as a truncated triangle with a triangular edge (121B) as a support portion (121) for the membrane (2).

8. 8. A tray (1) according to any one of claims 1 to 7, wherein the ridges (12) are evenly distributed over the area of ​​the ground layer (11).

9. 9. The tray (1) according to any one of claims 1 to 8, wherein the ridges (12) are arranged in a plurality of rows (120), the rows (120) extending perpendicular to the general flow direction (100), the rows (120) being evenly distributed along the general flow direction (100) and spaced apart by a row spacing (d).

10. 10. The tray (1) according to claim 9, wherein the ridges (12) arranged in a row (120) are spaced apart from one another by a gap distance (c) in the direction of the row (120).

11. A tray (1) according to any one of claims 1 to 10; An algae culture layer (2); An algae cultivation system comprising:

12. 12. The system according to claim 11, wherein the algae culture layer (2) is formed by a fluid-permeable membrane.

13. 13. The system according to claim 11 or 12, wherein the algae culture layer (2) is formed by a hydrophilic culture membrane with a pore size of less than 50 μm.

14. 14. The system according to any one of claims 11 to 13, wherein the algae culture layer (2) is formed by an algae culture membrane with a thickness of less than 50 μm and / or a pore size of less than 50 μm, preferably made of polybutylene terephthalate.

15. 15. The system of claim 11, further comprising a liquid supply unit configured to be positioned in the region of the first end (13) of the ground layer (11), the liquid supply unit further configured to uniformly supply the algae culture fluid to the first end (13) of the ground layer (11).

16. 16. Use of an algae cultivation system according to any one of claims 11 to 15 for the cultivation of microalgae, in particular for the cultivation of astaxanthin-containing microalgae.

Images