A distributed microalgae photobioreactor and microalgae cultivation method

Abstract

This invention provides a distributed microalgae photobioreactor and a method for cultivating microalgae. The reactor includes an environmental control chamber, which is at least partially transparent to light. A rotating support frame is located within the environmental control chamber and is connected to a rotation drive mechanism. The rotating support frame supports multiple independent cultivation containers, which are used to hold culture medium and microalgae respectively. The rotation mechanism drives the rotating support frame to rotate, thereby causing the multiple cultivation containers to rotate. The technical solution of this invention achieves physical isolation through independent cultivation containers, ensuring high aseptic reliability. It also achieves efficient mixing, low energy consumption, high and directionally controllable supplemental lighting, and has a wide range of applications and strong practicality.

Description

Technical Field

[0001] This invention relates to the field of microalgae cultivation technology, and in particular to a distributed microalgae photobioreactor and a microalgae cultivation method. Background Technology

[0002] Microalgae, as an important biological resource, show broad application prospects in food, feed, bioenergy, and high-value-added chemicals. Based on different nutritional methods, their cultivation modes are mainly divided into three types: autotrophic, heterotrophic, and polytrophic. Among them, the polytrophic mode can simultaneously utilize light energy and organic carbon sources, theoretically possessing higher growth efficiency and biomass yield, making it a potentially preferred approach for high-density microalgae cultivation.

[0003] However, polyculture faces a series of significant technical bottlenecks during large-scale scaling: First, the introduction of organic carbon sources (such as glucose) makes the culture medium highly susceptible to contamination by other microorganisms, requiring the culture system to have extremely high aseptic capabilities. While traditional large-scale fermenters can be used for heteroculture, their autoclaving is difficult and costly, and maintaining strict aseptic conditions throughout the entire culture cycle is complex and risky. Second, polyculture requires providing effective light and organic carbon to microalgae simultaneously. Achieving uniform and sufficient light inside large reactors is particularly challenging. Currently, a common solution is to install LED lights inside the stainless steel tank for supplemental lighting, but this method suffers from limited light penetration depth, high energy consumption, complex equipment structure, and difficulty in cleaning and maintenance.

[0004] Furthermore, centralized, integrated design is one of the mainstream approaches in existing photobioreactor technologies. These devices typically integrate multiple culture units into a complex mechanical system to achieve unified control of conditions such as illumination and agitation. While this highly integrated structure offers convenience in control, it also results in a lack of physical isolation between the culture units, posing significant challenges to the overall system's airtightness and aseptic control. Simultaneously, scaling up such systems often relies on redesigning and manufacturing the entire structure, making it difficult to flexibly and cost-effectively adapt to different production scales or process adjustments, thus limiting their modularity and scalability. Summary of the Invention

[0005] To address the above technical problems, this invention discloses a distributed microalgae photobioreactor and a microalgae cultivation method, which solves the problems of difficult culture medium sterilization, easy contamination, high energy consumption, and difficulty in large-scale scale-up during microalgae co-culture.

[0006] The technical solution adopted by this invention is as follows: A distributed microalgae photobioreactor includes an environmental control chamber, which is at least partially transparent to light. A rotating support frame is provided inside the environmental control chamber. The rotating support frame is connected to a rotation drive mechanism. The rotating support frame supports multiple independent culture containers, which are used to hold culture media and microalgae, respectively. The rotation drive mechanism drives the rotating support frame to rotate, thereby causing the multiple culture containers to rotate.

[0007] When using this distributed microalgae photobioreactor for microalgae cultivation, sterilized culture medium is first filled into an independent, sterile cultivation container and inoculated with microalgae. The cultivation container is then placed on the rotating support frame. The rotation drive mechanism is activated to rotate the cultivation container around the central axis of the column, and cultivation begins. The temperature, light intensity, and rotation status of the rotating support frame can be controlled in real time through an environmental monitoring and control system. The light quality of the supplemental lighting source can be adjusted according to the microalgae cultivation stage; blue and red light are used to promote microalgae growth in the early stage of cultivation, while red and yellow light are used to promote microalgae lipid accumulation in the later stage.

[0008] This technical solution solves the technical problems of difficult high-pressure sterilization of culture medium, easy contamination, uneven light and high energy consumption in microalgae polyculture by using independently designed distributed culture containers. It has the advantages of modularity, scalability and low energy consumption, and is suitable for autotrophic, heterotrophic and polytrophic culture of microalgae.

[0009] As a further improvement of the present invention, a stirring medium is placed inside the culture container to assist in stirring during rotation and enhance the mixing effect inside the culture container.

[0010] As a further improvement of the present invention, the culture container is a tissue culture flask.

[0011] As a further improvement of the present invention, the stirring medium is glass beads.

[0012] As a further improvement of the present invention, the number of glass beads is 3-5.

[0013] As a further improvement of the present invention, the rotating bearing frame includes a column, the column being fixedly connected to a multi-layer bearing platform, the column being connected to a rotation drive mechanism, and the bearing platform being used to support culture containers; or the column is provided with multiple detachably connected independent bottle racks, and the culture containers are located inside the bottle racks.

[0014] As a further improvement of the present invention, the bottle rack is a stainless steel annular bottle rack, which improves the mechanical strength and corrosion resistance of the equipment.

[0015] As a further improvement of the present invention, a fixed cantilever is provided on the inner side of the bottle rack; the fixed cantilever is fixedly connected to the column by bolts, or the column has multiple positioning holes, and the end of the fixed cantilever is provided with a hook, which is connected to the positioning hole. The bottle rack can be fixedly connected to the hollow column by the fixed cantilever on its inner side with bolts, or it can be suspended in the multiple positioning holes of the hollow column by the hook at the end of its cantilever. Both connection methods can realize the flexible assembly and disassembly of the bottle rack and the adjustment of the layer spacing, adapting to the needs of different cultivation scales.

[0016] As a further improvement of the invention, the bottle holder is suspended in the positioning hole by a hook at the end of its cantilever.

[0017] As a further improvement of the present invention, the bottle rack is a stainless steel annular bottle rack.

[0018] As a further improvement of the present invention, each layer of the multi-layer bearing platform is connected to an independent layer drive motor, which is used to realize independent rotation control of each layer bearing platform.

[0019] As a further improvement of the present invention, the material of the bearing platform is transparent or semi-transparent material such as acrylic.

[0020] As a further improvement of the present invention, a physical light-blocking layer is provided between each layer of the support platform to prevent light from interfering with each other between different layers.

[0021] As a further improvement of the present invention, the bottom of the culture container is provided with a rotating bearing base. When the rotating support frame rotates, it can induce the culture container to rotate around its own axis. The motion mode of combining revolution and rotation can significantly enhance the stirring effect inside the bottle and optimize the microalgae growth environment.

[0022] As a further improvement of the present invention, the column is a hollow column, and a supplementary light source is provided inside the hollow column. The supplementary light source includes LED tubes or light strips capable of emitting light of different wavelengths, and the LED tubes or light strips are used to adjust the light quality. This technical solution achieves artificial lighting "from the inside out," complementing the natural light entering from the outside. The growth and metabolism of microalgae can be regulated by adjusting the light intensity and quality of the LEDs.

[0023] Furthermore, the interior of the environmental control cabin is also equipped with multiple LED light strips to further enhance the supplementary lighting effect.

[0024] As a further improvement of the present invention, the environmental control chamber includes a transparent acrylic shell with an openable door. Using this technical solution, the environmental control chamber forms a relatively clean cultivation space, effectively isolating external dust, microorganisms, and rainwater. The transparent structure ensures the entry of natural light, and the openable door facilitates the placement and removal of cultivation containers and equipment maintenance. Furthermore, the acrylic shell is provided with a loading / unloading port.

[0025] As a further improvement of the present invention, the distributed microalgae photobioreactor also includes an environmental monitoring and control system, which includes at least one of a temperature sensor, a light sensor, and a rotation speed regulator.

[0026] As a further improvement of the present invention, the environmental monitoring and control system integrates temperature sensors, illuminometers, light regulators, rotary regulators, air conditioners, etc., to realize real-time monitoring and precise control of the culture environment.

[0027] This invention provides a method for cultivating microalgae using a distributed microalgae photobioreactor as described above, comprising the following steps: Step S1: Fill sterilized culture medium into an independent sterile culture container and inoculate microalgae; Step S2: Place the culture container on the rotating support frame; In step S3, the rotation drive mechanism is activated to rotate the culture container around the central axis and begin cultivation. In step S3, the temperature, light intensity, and rotational state of the rotating support frame of the cultivation environment are controlled in real time by the environmental monitoring and control system. The light quality of the supplemental light source can be adjusted according to the microalgae cultivation stage; blue and red light are used to promote microalgae growth in the early stage of cultivation, while red and yellow light are used to promote microalgae lipid accumulation in the later stage.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: First, high aseptic reliability: Cultivation is carried out in independent culture containers, achieving physical isolation. Contamination in a single culture container will not spread to other containers, thus dispersing the risk. Furthermore, the aseptic filling technology for these culture containers is mature and easily applied in industry.

[0029] Secondly, efficient mixing and low energy consumption: Through the combined action of the rotating support frame and the stirring medium within the culture container, gentle yet effective mixing is achieved, eliminating the need for a complex aeration system and significantly reducing energy consumption. Furthermore, time-sharing and layered rotation control can further optimize energy distribution and improve energy utilization efficiency. Additionally, by incorporating a rotating bearing base at the bottom of the culture container, utilizing its revolution and rotation design, more uniform mixing can be achieved at lower speeds, further reducing energy consumption and optimizing the microalgae growth environment.

[0030] Third, the supplemental lighting is highly efficient and can be directionally controlled: the hollow column is used for internal artificial lighting, which is combined with external natural light. This fully utilizes natural light while solving the problem of light attenuation in deep culture medium, thus improving the overall supplemental lighting efficiency. Furthermore, the use of LED tubes or strips that can emit different wavelengths allows for flexible adjustment of light quality and intensity according to the needs of microalgae cultivation, providing the possibility for directional control of microalgae growth and product synthesis.

[0031] Fourth, it is highly modular and scalable: It adopts standardized culture containers and multi-layer support platform design, and can easily achieve scale-up by increasing the number of platform layers or culture containers. It is flexible in disassembly and assembly and easy to maintain.

[0032] Fifth, it has a wide range of applications: This reactor is not only suitable for the most technically challenging microalgae polyculture, but also allows for adjustment of culture conditions according to needs, adapting to both autotrophic and heterotrophic microalgae culture. It has application value in multiple fields of microalgae culture and is highly practical. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the distributed microalgae photobioreactor of Embodiment 1 of the present invention;

[0034] Figure 2 This is a cross-sectional structural diagram of the multi-layer bearing platform and hollow column of Embodiment 1 of the present invention.

[0035] Figure 3 This is a schematic diagram of the hierarchical independent control structure in Embodiment 3 of the present invention.

[0036] Figure 4 This is a schematic diagram of the bearing base and the rotation principle of the culture container in Embodiment 4 of the present invention.

[0037] Figure 5 This is a schematic diagram of the modular adjustable hanging bottle rack of Embodiment 5 of the present invention.

[0038] Figure 6 This is a schematic diagram of the hook-type quick-release bottle rack according to Embodiment 6 of the present invention.

[0039] Reference numerals: 1 - Column, 2 - LED light strip, 3 - Door, 4 - Tissue culture bottle, 5 - Supporting platform, 6 - Environmental control chamber, 7 - Control panel, 8 - Screen, 9 - Temperature sensor, 10 - Rotary drive mechanism, 11 - Layer rotation drive mechanism, 12 - Rotary bearing base, 13 - Load-bearing bracket, 14 - Bottle rack, 15 - Fixed cantilever, 16 - Positioning hole, 17 - Cantilever hook. Detailed Implementation

[0040] The preferred embodiments of the present invention will be described in further detail below.

[0041] Example 1

[0042] like Figure 1 and Figure 2 As shown, a distributed microalgae photobioreactor comprises a multi-layered circular support platform 5 made of acrylic. A hollow column 1 is located at the center of the platform 5, with a rotary drive mechanism 10 connected to its bottom. Supplementary lighting sources, including full-spectrum LED strips 2, are evenly arranged inside the column 1. The light intensity and period can be adjusted by a controller. The column 1 is made of stainless steel. The rotary drive mechanism 10 is a servo motor with adjustable speed.

[0043] Each support platform can hold ten 1000mL culture containers. In this embodiment, the culture containers are sterile tissue culture flasks 4, and each flask 4 contains a stirring medium, which in this embodiment consists of five 5mm diameter glass beads. The entire support platform 5 is enclosed by an environmental control chamber 6, which includes a transparent acrylic shell. The side of the environmental control chamber 6 has an openable door 3 with a sealing strip. Inside, a temperature sensor 9, a lux meter, and a small fan are installed. All sensors and actuators are connected to an environmental monitoring and control system, which includes a central PLC controller.

[0044] This embodiment also provides a microalgae cultivation method using the above system, including the following steps:

[0045] S1. In a clean bench, fill a 1000mL sterile tissue culture bottle with sterile culture medium containing glucose and complete the microalgae inoculation.

[0046] S2. Place the inoculated tissue culture bottle in the designated position on the support platform;

[0047] S3. Close the door of the environmental control chamber, start the rotary drive mechanism, and set the rotation speed of the carrying platform to 10-15 rpm. The full-spectrum LED light strip adopts a light cycle of 12 hours of light and 12 hours of darkness for supplemental lighting. During the cultivation period, the temperature and light intensity are monitored in real time through the central PLC controller, and a small fan is used to maintain air circulation and temperature balance. By observing the color and turbidity of the algal solution in individual tissue culture bottles, bottles suspected of being contaminated are removed in a timely manner without affecting the normal operation of other parts of the system. After the cultivation is completed, the microalgal biomass in each tissue culture bottle is harvested uniformly.

[0048] Example 2

[0049] Based on Example 1, this example optimizes the system control method intelligently. The central PLC controller can automatically adjust the start, stop and speed of the fan on the environmental control chamber according to the feedback of the temperature sensor to achieve automatic temperature control. At the same time, the central PLC controller is programmed to drive only two of the support platforms to rotate for 30 minutes every 4 hours and cycle through them, so as to ensure the mixing effect in the tissue culture bottle while minimizing motor energy consumption.

[0050] The microalgae cultivation method in this embodiment is based on Example 1, but the supplementary light quality is adjusted according to the microalgae cultivation stage: in the early stage of cultivation, the LED light strip is adjusted to blue and red light to promote rapid growth of microalgae; in the later stage of cultivation, the LED light strip is switched to red and yellow light to promote the accumulation of microalgae oil and increase the yield of the target product.

[0051] Example 3

[0052] like Figure 3 As shown, this embodiment optimizes the rotating bearing frame based on embodiment 1 or 2, and adopts a layered independent control design: the rotating bearing frame carries multiple independent bearing platform layer units, each bearing platform layer unit is equipped with an independent layer rotation drive mechanism 11 connected to the bearing platform layer unit, which can realize independent rotation speed and start-stop time control of each layer; the inner wall of the environmental control cabin 6 corresponding to each layer unit is attached with an independent LED light strip supplementary lighting unit, which realizes independent adjustment of light intensity and light quality of each layer; a black physical light blocking layer is added between each layer unit to avoid mutual interference of light between different layers.

[0053] Furthermore, the system's intelligent control system is connected to the central controller via an IoT module. Users can remotely and hierarchically control the entire system through computer software or a mobile app. Different culture conditions can be set at different levels, enabling multiple experiments to be conducted simultaneously and improving equipment utilization efficiency.

[0054] Example 4

[0055] like Figure 4 As shown, in this embodiment, based on any of the aforementioned embodiments, a rotating bearing base 12 is added at the contact position between the bottom of each tissue culture bottle 4 and the support platform 5. This rotating bearing base 12 is connected to the support platform 5 via a bearing structure with a low coefficient of friction. When the support platform 5 rotates at a lower speed, it induces the tissue culture bottle 4 to revolve around the column 1 while simultaneously rotating around its own central axis. This combined revolution and rotation motion significantly enhances the complexity and kinetic energy of the glass beads' movement trajectory within the tissue culture bottle 4, achieving more vigorous and uniform liquid stirring with lower overall speed and energy consumption, further optimizing the microalgae growth environment.

[0056] Example 5

[0057] like Figure 5 As shown, in this embodiment, based on embodiment 1, the fixed multi-layer support platform is replaced with multiple bottle racks 14. The bottle rack 14 is a stainless steel ring bottle rack, which is connected to the load-bearing bracket 13. Multiple fixed cantilever arms 15 extend radially from the inner side of the bottle rack 14. The ends of the fixed cantilever arms 15 are provided with connecting holes and are fixedly connected to the column 1 by bolts. The bottle rack 14 is provided with multiple bottle support holes that match the shape of the tissue culture bottle 4, which are used to stably support the tissue culture bottle 4 and prevent it from slipping during rotation.

[0058] The stainless steel bottle racks enhance the system's mechanical strength, corrosion resistance, and service life, making them suitable for harsh industrial cultivation environments. Operators can flexibly increase or decrease the number of ring-shaped bottle racks on the hollow columns according to the actual cultivation scale, or change the layer spacing by adjusting the bolt positions to achieve height configuration as needed.

[0059] Example 6

[0060] like Figure 6 As shown, this embodiment optimizes the connection method between the bottle rack 14 and the column 1 based on embodiment 5. A series of positioning holes 16 are opened along the axial direction on the wall surface of the column 1. The end of the fixed cantilever 15 on the inner side of the bottle rack 14 is provided with a cantilever hook 17 that matches the positioning hole 16. The operator can directly hang the cantilever hook 17 of the bottle rack 14 into any positioning hole 16 of the column 1, and complete the installation, disassembly or height adjustment of a single bottle rack without any tools.

[0061] This design significantly improves the ease of bottle rack assembly and disassembly, making equipment cleaning, maintenance, and reconfiguration of the culture layout more efficient, and further enhancing the system's flexibility and practicality.

[0062] The distributed microalgae photobioreactor system and its cultivation method of this invention solve key technical problems in microalgae polyculture, such as aseptic control, light supply, energy consumption, and large-scale scale-up. It boasts advantages such as high aseptic reliability, low energy consumption, high supplemental lighting efficiency, strong modular scalability, and wide applicability. The system's structural design is simple and reasonable, facilitating disassembly and maintenance. The cultivation method is convenient to operate, enabling high-density, directional cultivation of microalgae. It is suitable not only for laboratory microalgae cultivation research but also for easy large-scale industrial applications, possessing significant industrial application value in microalgae-related fields such as food, feed, and bioenergy, and is easy to promote and implement.

[0063] It should be noted that, unless otherwise specified, the “connection” mentioned in this invention refers to conventional mechanical connection methods, such as bolt connection, hook connection, bearing connection, etc., and those skilled in the art can make reasonable selections according to actual needs.

[0064] Furthermore, the specifications and quantities of each component of the distributed microalgae photobioreactor system of the present invention can be flexibly adjusted according to the cultivation scale, and are not limited to the values ​​in the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0065] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A distributed microalgae photobioreactor, characterized in that: The device includes an environmental control chamber, which is at least partially transparent to light. A rotating support frame is provided inside the environmental control chamber. The rotating support frame is connected to a rotation drive mechanism. The rotating support frame supports multiple independent culture containers, which are used to hold culture media and microalgae, respectively. The rotation mechanism drives the rotating support frame to rotate, thereby causing the multiple culture containers to rotate.

2. The distributed microalgae photobioreactor according to claim 1, characterized in that: The culture container contains a stirring medium to enhance the mixing effect within the container during rotation.

3. The distributed microalgae photobioreactor according to claim 1, characterized in that: The rotating support frame includes a column, which is fixedly connected to a multi-layer support platform. The column is connected to a rotation drive mechanism, and the support platform is used to support the culture container. Alternatively, the column may be equipped with multiple detachably connected bottle racks, with the culture containers located within the bottle racks.

4. The distributed microalgae photobioreactor according to claim 3, characterized in that: The bottle rack has a fixed cantilever on its inner side; the fixed cantilever is fixedly connected to the column by bolts, or the column has multiple positioning holes, and the end of the fixed cantilever has a hook, which is connected to the positioning hole.

5. The distributed microalgae photobioreactor according to claim 3, characterized in that: Each layer of the multi-layer support platform is connected to an independent layer drive motor, which is used to realize independent rotation control of each layer support platform; a physical light-blocking layer is set between each layer support platform to avoid mutual interference of light between different layers.

6. The distributed microalgae photobioreactor according to claim 1, characterized in that: The bottom of the culture container is provided with a rotating bearing base, which can induce the culture container to rotate around its own axis when the rotating support frame rotates.

7. The distributed microalgae photobioreactor according to claim 1, characterized in that: The column is a hollow column, and a supplementary light source is provided inside the hollow column. The supplementary light source includes LED tubes or light strips that can emit light of different wavelengths, and the LED tubes or light strips are used to adjust the light quality.

8. The distributed microalgae photobioreactor according to claim 1, characterized in that: The environmental control cabin includes a transparent acrylic shell, an openable door, and multiple LED light strips inside the shell.

9. The distributed microalgae photobioreactor according to any one of claims 1 to 8, characterized in that: It also includes an environmental monitoring and control system, which includes at least one of a temperature sensor, a light sensor, and a rotation speed regulator.

10. A method for cultivating microalgae, characterized in that: Cultivation using the distributed microalgae photobioreactor as described in any one of claims 1-9 includes the following steps: Step S1: Fill sterilized culture medium into an independent sterile culture container and inoculate microalgae; Step S2: Place the culture container on the rotating support frame; In step S3, the rotation drive mechanism is activated to rotate the culture container around the central axis and carry out the culture. In step S3, the temperature, light intensity, and rotation state of the rotating support frame of the culture environment are controlled and adjusted in real time through an environmental monitoring and control system.

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