Microalgae photobioreactor coupled with light guide plate and microporous pipe

Abstract

The present invention relates to the technical field of microalgae photobioreactors, and discloses a light guide plate and microporous pipe coupled microalgae photobioreactor, the reactor comprises: a device body unit, which comprises a reactor body, a light guide plate assembly embedded in the side wall of the reactor body, and a hollow microporous pipe assembly; the light source is cooperatively arranged at the end part of the light guide plate assembly; the light guide plate assembly comprises a plurality of sets of light guide plates distributed in parallel, and the ends of the adjacent light guide plates are staggered. One end of the light guide plate extends out of the reactor body and forms an incident end; a flow channel is formed between each light guide plate and the wall surface of the inner cavity of the reactor body; the photobioreactor with a novel structure is designed, the light guide plate with excellent light transmission performance and the hollow microporous pipe are introduced into the culture of the haematococcus pluvialis, and on the premise that the occupied area of the reactor is not increased, the culture operation of the haematococcus pluvialis is simpler and more convenient and the culture operation is efficient through the integrated structure; and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of microalgae photobioreactors, and in particular to a microalgae photobioreactor coupled with a light guide plate and a microporous tube. Background Art

[0002] Microalgae cells are rich in pigments, phycobiliproteins, polyunsaturated fatty acids and other bioactive substances, which can be used to produce a variety of functional foods and health products, with great market demand and important economic value. Among them, Haematococcus pluvialis is recognized as the most commercially valuable natural astaxanthin source because it can accumulate astaxanthin in large quantities under environmental stress conditions. Astaxanthin has physiological functions such as preventing cardiovascular and cerebrovascular diseases, inhibiting tumors, and enhancing immunity, and is widely used in food, health products, pharmaceuticals and other industries. It has broad application prospects and huge market potential.

[0003] The photoautotrophic growth of microalgae is carried out in a photobioreactor. An efficient photobioreactor is the key to achieving high-density culture of microalgae and large-scale synthesis of specific target products. Unlike most microalgae, Haematococcus pluvialis cells have complex and unique growth characteristics. At present, it is internationally recognized that the entire growth period of Haematococcus pluvialis is divided into a green nutritional stage (green stage) and a red thick-walled spore stage (red stage). In the green stage, Haematococcus pluvialis rapidly divides and proliferates in the form of green motile cells with flagella under suitable growth conditions (such as low light, sufficient nutrients, moderate salinity, etc.), and the biomass concentration increases; when Haematococcus pluvialis cells are in an unfavorable growth environment (such as high light, lack of nutrients, high salinity, etc.), the green motile cells gradually lose their flagella and gradually transform into green immotile cells and yellow immotile cells, and finally form red cysts. During this transformation process, the cell volume increases significantly, the intracellular chlorophyll content decreases, and oil and astaxanthin are synthesized in large quantities in the cells. The cell color changes from green to red, and this stage is the red stage. It can be seen from this that the accumulation of biomass in the green stage is a prerequisite for the large-scale synthesis of target products such as oil and astaxanthin in the later red stage.

[0004] It is worth noting that due to the significant differences in the environmental factors required for the green and red stages of Haematococcus pluvialis, the "two-step method" is currently the most commonly used and mature Haematococcus pluvialis cultivation process and has been commercially applied. For this process, the green and red stages of Haematococcus pluvialis are carried out in two different photobioreactors, that is, the green stage of Haematococcus pluvialis is first cultivated in one reactor; then, the high-density green swimming cell suspension of Haematococcus pluvialis is transferred to another reactor, and the sporangium of Haematococcus pluvialis cells is promoted by applying environmental stress conditions such as high light and high salt, and a large amount of oil and astaxanthin are accumulated in the thick-walled spores. However, this process has bottleneck problems such as the need for multiple reactors, high cost, long cycle, and complex operation. In recent years, integrated reactors have become an important direction for the development of current biochemical reactors due to their advantages such as small footprint, convenient operation, and low operating cost. However, there are few reports on the research of integrated photobioreactors suitable for Haematococcus pluvialis to fix CO2 and produce oil and astaxanthin. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems existing in the existing reactors used for light growth of Haematococcus pluvialis, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to provide a microalgae photobioreactor coupled with a light guide plate and a microporous tube, which is used for fixing CO2 and co-producing oil and astaxanthin by Haematococcus pluvialis, and the synchronous and efficient progress of the green stage and the red stage of Haematococcus pluvialis in the same reactor is achieved through the coordinated regulation of light energy transfer and material transfer.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a microalgae photobioreactor coupled with a light guide plate and a microporous tube, the reactor comprising a body unit and a light source, wherein the body unit comprises a reactor body, a light guide plate assembly embedded in the side wall of the reactor body, and a hollow microporous tube assembly; the light source is cooperatively arranged at the end of the light guide plate assembly.

[0009] As a preferred solution of the microalgae photobioreactor coupled with light guide plates and microporous tubes described in the present invention, the light guide plate assembly includes a plurality of groups of light guide plates distributed in parallel, and the ends of adjacent light guide plates are staggered with each other; one end of the light guide plate extends to the outside of the reactor body and forms an incident end; a flow channel is formed between each light guide plate and the inner cavity wall of the reactor body.

[0010] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention, the reactor body has an inlet at the top and an outlet at the bottom, and the inlet and outlet are respectively connected to the flow channel.

[0011] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention, reflective films are installed on the top plate surface and the side plate surface of the light guide plate located in the cavity of the reactor body.

[0012] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tubes of the present invention, the hollow microporous tube assembly includes a plurality of hollow microporous tubes, and each of the hollow microporous tubes is evenly distributed in the flow channel.

[0013] As a preferred embodiment of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention, the suspension of Haematococcus pluvialis cells enters the flow channel in the reactor body cavity from the inlet and is finally discharged from the outlet.

[0014] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention, micropores are evenly arranged in the wall of the hollow microporous tube, and the average pore size of each micropore is smaller than the diameter of the Haematococcus pluvialis cell.

[0015] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention, the body unit is divided into a green stage area, an induced transformation transition area and a red stage area from top to bottom in the height direction; each area corresponds to the growth change process of Haematococcus pluvialis cells.

[0016] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tube described in the present invention, the light source includes a plurality of light strips, each of which is correspondingly attached to the side wall of the incident end of the light guide plate; the light of the light strips is emitted into the flow channel through the exit end formed by the bottom plate surface of the light guide plate.

[0017] As a preferred solution of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention, the length and width of the light bar are matched with the size of the incident end of the light guide plate.

[0018] Beneficial effects of the present invention:

[0019] The present invention designs a photobioreactor with a novel structure, and introduces a light guide plate and a hollow microporous tube with excellent light transmission performance into the cultivation of Haematococcus pluvialis. The novel structure makes the cultivation operation of Haematococcus pluvialis simpler and more convenient through an integrated structure without increasing the floor space of a single reactor, and the cultivation operation is efficient and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0021] Figure 1 The schematic diagram is a schematic diagram of the overall structure of a microalgae photobioreactor coupled with a light guide plate and a microporous tube according to the present invention.

[0022] Figure 2 The schematic diagram of the operation state of the microalgae photobioreactor coupled with the light guide plate and the microporous tube according to the present invention.

[0023] Figure 3 It is a schematic diagram of the partial F-enlarged structure of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention.

[0024] Figure 4 The schematic diagram of the working process of the hollow microporous tube of the microalgae photobioreactor coupled with the light guide plate and the microporous tube of the present invention.

[0025] Figure 5 The diagram is a schematic diagram of the division of regions of a microalgae photobioreactor coupled with a light guide plate and a microporous tube according to the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0030] Example 1

[0031] Reference Figures 1 to 5 , which is the first embodiment of the present invention, provides a microalgae photobioreactor coupled with a light guide plate and a microporous tube, the reactor comprising a body unit 100 and a light source 200, wherein the body unit 100 is the main structure of the photobioreactor, and the reactor is filled with a culture solution of Haematococcus pluvialis; the light source 200 is used to provide light for the growth of Haematococcus pluvialis.

[0032] Specifically, the body unit 100 includes a reactor body 101, a light guide plate assembly 102 embedded in the side wall of the reactor body 101, and a hollow microporous tube assembly 103; wherein the reactor body 101 is a container structure, which can be made of existing common materials, and the light guide plate assembly 102 can be built in or embedded in the reactor body 101 structure. In this embodiment, it is preferably an embedded structure; the light guide plate assembly 102 is used to guide and control the incident light to achieve the best lighting effect, and the selection of the light guide plate 102a includes but is not limited to a nano light guide plate, a laser engraved light guide plate, a silk screen light guide plate, and a light guide plate with a chemically corroded surface and a specific texture structure; the hollow microporous tube assembly 103 is built in the reactor to provide CO2 and inorganic nutrients (such as nitrates, phosphates, etc.) required for the growth of Haematococcus pluvialis cells, and to discharge the dissolved oxygen in the suspension of Haematococcus pluvialis cells in time to avoid the inhibitory effect of excessive dissolved oxygen concentration on the growth of Haematococcus pluvialis cells.

[0033] Furthermore, the reactor body 101 has an inlet 101a at the top and an outlet 101b at the bottom, and the inlet 101a and the outlet 101b are used for the algae culture solution and the Haematococcus pluvialis cell suspension to enter and discharge, respectively. Both the inlet 101a and the outlet 101b are in communication with the flow channel L.

[0034] The light guide plate assembly 102 includes a plurality of light guide plates 102a distributed in parallel. Each light guide plate 102a is embedded in layers in the height direction of the reactor body 101. However, the ends of adjacent light guide plates 102a are mutually offset. Figure 1 and 2As shown in the figure, the end positions of the light guide plates 102a of the spacer layer are aligned, and flow channels that are parallel and connected in series are formed between each light guide plate 102a and the inner cavity wall of the reactor body 101, namely, the flow channel L, and the algae culture solution and the Haematococcus pluvialis cell suspension will grow and flow in the flow channel L.

[0035] Furthermore, regarding the distribution position of the light guide plate 102a, one end thereof is attached to the side wall of the reactor body 101 or extends outside the reactor body 101, serving as the incident surface of the light source, namely, the incident end R; in this embodiment, it is preferably extended outside the reactor body 101. The incident end R is used to install the light source 200, so that the light is incident into the flow channel L through the light guide plate 102a.

[0036] It should be noted that the light guide plate 102a is installed with reflective films 102b on the top plate surface and the side plate surface located in the cavity of the reactor body 101. Furthermore, the remaining surfaces of the light guide plate 102a except the outer end surface (i.e., the incident end R) and the lower surface (the light source exit surface, i.e., the exit end S) are all pasted with reflective films with a light reflectivity of up to 95-100%, so that as much light as possible incident from the light source to the light guide plate 102a can be emitted into the Haematococcus pluvialis cell suspension in the reactor.

[0037] The hollow microporous tube assembly 103 includes a plurality of hollow microporous tubes 103a, each of which is evenly distributed in the flow channel L; preferably, it is distributed in the middle position of the flow channel L between adjacent light guide plates 102a; the hollow microporous tube 103a is used to provide CO2 and inorganic nutrients (such as nitrates, phosphates, etc.) required for the growth of Haematococcus pluvialis cells, and to discharge the dissolved oxygen in the suspension of Haematococcus pluvialis cells in time to avoid the inhibitory effect of excessive dissolved oxygen concentration on the growth of Haematococcus pluvialis cells. Specifically, driven by the concentration gradient, the transmission of inorganic nutrients such as nitrates and CO2 inside and outside the tube bundle can be achieved through diffusion and convection; at the same time, the O2 produced by photosynthesis of Haematococcus pluvialis cells can also diffuse into the hollow microporous tube and eventually leave the reactor, effectively avoiding the inhibitory effect of excessive accumulation of dissolved oxygen on the growth of Haematococcus pluvialis cells, such as Figure 4 shown.

[0038] Furthermore, in order to prevent the Haematococcus pluvialis cells from passing through the microporous tube and entering the interior of the hollow microporous tube, micropores are evenly arranged in the wall of the hollow microporous tube 103a, and the average pore size of each micropore is smaller than the diameter of the Haematococcus pluvialis cells; it should be noted that the commonly used average pore size of the microporous tube wall can be 0.22μm, 0.45μm, 0.8μm, 1.2μm, etc.

[0039] Furthermore, the body unit 100 as a whole is divided into a green stage region A, an induced transition region B and a red stage region C from top to bottom according to its height direction; each region corresponds to each growth change stage of the Haematococcus pluvialis cells. Figure 5 as shown in .

[0040] The transmission and distribution of light energy in the flow channels L in different regions are regulated by changing the power and spectral ratio of the light sources 200 in different regions, changing the structural dimensions of the reactor, modifying the surface of the light guide plate, etc. At the same time, the transmission and supply of CO2 and nitrate in the flow channels in different regions can also be regulated by changing the residence time of the algae cell suspension in different regions of the reactor, changing the number, size and arrangement of the hollow microporous filter tubes, and changing the CO2 gas concentration and flow rate in the hollow microporous tube 103a. By coordinating the transmission of light energy and the transfer of substances in the reactor, the green stage carbon fixation growth of Haematococcus pluvialis and the synthesis of the target product in the red stage can be achieved simultaneously and efficiently in the reactor.

[0041] Finally, a low-concentration Haematococcus pluvialis cell suspension in the green stage enters through the inlet 101a at the top of the reactor and flows along the flow channel L in the reactor. As the cultivation process proceeds, a high-cell-density and astaxanthin-rich Haematococcus pluvialis cell suspension in the red stage flows out from the outlet 101b at the bottom of the reactor.

[0042] The light source 200 is cooperatively disposed at the end of the light guide plate assembly 102 .

[0043] Specifically, the light source 200 includes a plurality of light strips 201, each light strip 201 is correspondingly attached to the side wall of the incident end R of the light guide plate 102a, that is, the number of light strips 201 and the light guide plate 102a are the same and correspond one to one; the light of the light strip 201 is emitted into the flow channel L through the exit end S formed by the bottom plate surface of the light guide plate 102a.

[0044] It should be noted that the light strip 201 is preferably an LED light strip, and its length and width match the size of the incident end R of the light guide plate 102a; the purpose is to make the light generated by the light strip 201 irradiate the entire area within the light guide plate 102a, and under the action of the reflective film 102b, it can be emitted from the exit end S of its bottom plate surface.

[0045] Example 2

[0046] This is the second embodiment of the present invention, which is an example operation based on the reactor in Example 1, specifically comprising:

[0047] Haematococcus pluvialis FACHB-712, which has a fast growth rate and high lipid and astaxanthin content, was selected as the algae species. The liquid culture medium used for algae culture was a modified BG11 medium, in which sodium nitrate was changed to 0.2 g / L -1 , the contents of the other components remain unchanged; for the reactor, the wall of its body is made of 8mm thick transparent organic glass; the light guide plate 102a is a 4mm thick nano light guide plate made of polymethyl methacrylate and polycarbonate composite material and doped with light scattering particles, and the spacing between adjacent light guide plates 102a is 2cm; and the remaining surfaces of each light guide plate 102a except the incident end R and the exit end S are pasted with a reflective film 102b with a reflectivity of 95% and a thickness of 0.15 mm; the hollow microporous tube 103a uses a PTFE tube with a tube diameter of 5mm and an average wall pore diameter of 0.45μm, and the volume fraction of CO2 introduced into the tube is 2%; in the green stage area A of Haematococcus pluvialis, the light intensity emitted from the surface of the light guide plate is 100μmol〃m -2 〃s -1 The light intensity in the induced transition region B is 300 μmol〃m -2 〃s -1 , the light intensity in the red phase area C is 600 μmol〃m -2 〃s -1 .

[0048] The low concentration of green motile cell suspension of Haematococcus pluvialis enters the reactor through the feed port 101a on the top layer of the reactor driven by the pump. When it flows slowly forward along the flow channel L, it will successively experience the green stage area A, the induced transformation transition area B and the red stage area C. The light energy in each area is provided by the light bar 201, the nitrogen source and the carbon source are provided by the hollow microporous tube 103a, and the O2 produced by the photosynthesis of the algae cells is also removed by the hollow microporous tube 103a.

[0049] Specifically, in the green stage area A, the culture conditions such as low light intensity and sufficient nitrogen source are provided for the Haematococcus pluvialis cells, so that the Haematococcus pluvialis cells in the form of green swimming cells can divide and proliferate rapidly; then, in the induced transition area B, the light intensity is gradually increased and the nitrogen source supply is reduced to promote the transformation of the green swimming cells of the Haematococcus pluvialis into red cysts; then, when the high-concentration green swimming cell suspension of the Haematococcus pluvialis flows to the red stage area C, the green swimming cells are completely transformed into red cysts by applying environmental stress conditions such as high light and low nitrogen. Finally, the red cyst suspension of the Haematococcus pluvialis with high cell concentration, high oil and astaxanthin content flows out continuously from the discharge port 101b at the bottom of the reactor.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A microalgae photobioreactor coupled with a light guide plate and a microporous tube, characterized in that: include, A body unit (100) comprising a reactor body (101), a light guide plate assembly (102) embedded in a side wall of the reactor body (101), and a hollow microporous tube assembly (103); The light source (200) is arranged at the end of the light guide plate assembly (102).

2. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 1, characterized in that: The light guide plate assembly (102) comprises a plurality of groups of light guide plates (102a) distributed in parallel, and ends of adjacent light guide plates (102a) are staggered with each other; One end of the light guide plate (102a) extends outside the reactor body (101) to form an incident end (R); a flow channel (L) is formed between each light guide plate (102a) and the inner cavity wall of the reactor body (101).

3. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 2, characterized in that: The reactor body (101) has an inlet (101a) located at the top and an outlet (101b) located at the bottom, and the inlet (101a) and the outlet (101b) are respectively communicated with the flow channel (L).

4. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 3, characterized in that: Reflective films (102b) are installed on the top plate surface and the side plate surface of the light guide plate (102a) located in the cavity of the reactor body (101).

5. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 4, characterized in that: The hollow microporous tube assembly (103) comprises a plurality of hollow microporous tubes (103a), and each of the hollow microporous tubes (103a) is evenly distributed in the flow channel (L).

6. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 5, characterized in that: The Haematococcus pluvialis cell suspension (Y) enters the flow channel (L) in the cavity of the reactor body (101) from the feed inlet (101a), and is finally discharged from the discharge port (101b).

7. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 6, characterized in that: Micropores are evenly arranged in the wall surface of the hollow microporous tube (103a), and the average pore diameter of each micropore is smaller than the diameter of the Haematococcus pluvialis cell.

8. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 7, characterized in that: The body unit (100) is divided into a green stage area (A), an induced transformation transition area (B) and a red stage area (C) from top to bottom in the height direction; each area corresponds to the growth change process of Haematococcus pluvialis cells.

9. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 8, characterized in that: The light source (200) comprises a plurality of light bars (201), each of the light bars (201) being correspondingly attached to a side wall of the incident end (R) of the light guide plate (102a); Light from the light bar (201) is emitted into the flow channel (L) through an emission end (S) formed on the bottom plate surface of the light guide plate (102a).

10. The microalgae photobioreactor of coupled light guide plate and microporous tube according to claim 9, characterized in that: The length and width of the light bar (201) both match the size of the incident end (R) of the light guide plate (102a).

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