1. A photobioreactor system for culturing microalgae by magnetic field coupling is characterized by comprising a vertical tubular photobioreactor (3), an electromagnet (6), a first magnetic resistance plate (1), a second magnetic resistance plate (2), a rotating shaft (10), a rotating cylinder (11), a rotating table (12), a top supporting plate (13), a base (14) and a controller;

the top of the vertical tubular photobioreactor (3) is provided with a first air inlet pipe (8) and an air outlet pipe (9), and the bottom of the vertical tubular photobioreactor is provided with a second air inlet pipe (7); a first magnetic resistance plate (1) and a second magnetic resistance plate (2) are arranged around the vertical tubular photobioreactor (3), the first magnetic resistance plate (1) and the second magnetic resistance plate (2) are arranged on a base (14), the bottoms of the two opposite first magnetic resistance plates (1) are respectively in rotating connection with a rotating shaft (10) on the base (14), and electromagnets (6) are uniformly arranged on the two first magnetic resistance plates (1); the bottom of the vertical tubular photobioreactor (3) is placed in a through hole of a base (14), a rotating platform (12) is arranged below the base (14), and the rotating platform (12) can drive the base (14) to rotate; the rotary cylinder (11) is arranged on the top supporting plate (13), the rotary cylinder (11) is connected with the top of the vertical tubular photobioreactor (3), and the rotary cylinder (11) is used for lifting the vertical tubular photobioreactor (3) out of the through hole of the base (14); the controller is respectively connected with the electromagnet (6), the rotating table (12) and the rotating cylinder (11).

2. The photo-bioreaction system for microalgae cultivation by magnetic field coupling according to claim 1, further comprising three transparent baffles (4); the middle of three baffles (4) all is equipped with the through-hole to from the top down overlaps in proper order on vertical tubular photobioreactor (3), and baffle (4) are connected with first magnetic resistance board (1), are equipped with the draw-in groove on first magnetic resistance board (1), and install respectively in the draw-in groove at the both ends of baffle (4), and three baffles (4) divide into from the top down into upper, middle, lower three region with the space that first magnetic resistance board (1) and second magnetic resistance board (2) enclose.

3. The photobioreactor system for cultivating microalgae by magnetic field coupling as claimed in claim 2, further comprising a fluorescent plate (5); the fluorescent plate (5) is provided with a groove and is arranged on the baffle (4) through the groove; the fluorescent plate (5) is connected with the controller.

4. The photobioreactor system for cultivating microalgae by magnetic field coupling as claimed in claim 1, wherein the second magnetic resistance plate (2) comprises a vertical plate; the two sides of the vertical plate are respectively provided with a sector plate, a sliding groove is formed in the back of the vertical plate (2), the bottom of the sector plate is installed on the sliding groove, one side of the sector plate is connected with the vertical plate, the other side of the sector plate is connected with the first magnetic resistance plate (1), the first magnetic resistance plate (1) is pulled open towards the two sides, and the sector plate is driven to be unfolded.

5. The photobioreactor system for microalgae cultivation by magnetic field coupling as claimed in claim 1, wherein the vertical tubular photobioreactor (3) is transparent.

6. The photobioreactor system for microalgae cultivation by magnetic field coupling as claimed in claim 1, wherein the first and second gas inlet pipes (8, 7) are connected to CO, respectively₂The gas cylinders are connected.

7. A culture method of the photo-biological reaction system for microalgae culture by magnetic field coupling according to any one of claims 1-6, comprising the following steps:

step S1, adding the microalgae culture solution into a vertical tube type photobioreactor (3), wherein a first air inlet pipe (8) and a second air inlet pipe (7) of the vertical tube type photobioreactor (3) are respectively connected with CO₂Connecting the gas cylinders;

step S2, measuring the optical density of the microalgae in the culture period of the microalgae to determine different growth stages of the microalgae;

step S3, opening a magnetic field coupling culture in the exponential phase and the stable phase of microalgae growth, wherein the angle of the electromagnet (6) is adjusted to change the density of the magnetic field in the area;

step S4, after magnetic field coupling culture, turning off the magnetic field, and detecting the dry weight of the cells;

and step S5, separating the magnetic particles from the microalgae by using an electromagnetic field to realize secondary utilization of the magnetic particles, and weighing the cultured microalgae after centrifugal drying.

8. The method of claim 7, wherein the light-to-dark ratio in step S2 is 12: 12, the room temperature is 25 ℃, the intensity of the environmental magnetic field is measured by using a gaussmeter, the optical density of the sample is measured by using an optical density instrument in an ABS mode, and the growth time of the microalgae is in direct proportion to the optical density, so that the growth trend of the microalgae under the magnetic field condition is judged.

9. The method of claim 7, wherein the magnetic field strength in step S3 is 30-60 mT, the electromagnetic field is intermittently turned on, and the duration of the magnetic field is controlled.

10. The method for culturing the photobioreactor system for culturing the microalgae in the claim 7, wherein the rotation speed of the centrifuge is 4000 to 5000rmp in the step S5, the centrifuge is centrifuged for 10 to 15min, and the dry weight of the microalgae is determined by drying in an oven at 60 ℃.

Background

CO₂Is a major cause of global warming. With the rapid development of emerging economies, global energy consumption will rise dramatically, which will lead to more environmental damage. Thus, while reducing carbon dioxide emissions, there is a desire to find cleaner renewable energy sources.

Now, biodiesel and bioethanol are developed as alternatives to fossil fuels such as petroleum. Sugarcane, corn and other oilseed plants are crops with the highest capacity of producing bioethanol, and oil seeds of soybean and the like are crops with the highest capacity of producing biodiesel. However, the growth of these crops occupies too much space and affects the growth of other organisms, and researches show that if the crops rely on biofuel completely at the present stage, the growth of the raw crops occupies 61 percent of the agricultural land, the normal operation of the human society is affected, and the diversity of the terrestrial organisms is also affected. The microalgae used as the third-generation biological energy source raw material has the advantages of short growth period, no land occupation, strong photosynthesis and the like. In terms of lipid accumulation, microalgae are approximately 80% higher than other feedstocks and, in addition to being high in lipid content, contain many other by-products such as proteins, carbohydrates, pigments, etc. The added value of these by-products can offset the production cost to some extent, so the accumulated target product is selected when culturing microalgae. In addition, the yield of microalgae is improved, and the yield of biofuel is improved, so that the market competitiveness of the biofuel is enhanced. Different growth conditions can affect the growth tendency of microalgae, such as temperature, metal ion concentration, PH, etc.

Studies have shown that external magnetic fields can stimulate microalgae growth, algal cells contain many complex cellular components that are susceptible to magnetic field interference, such as electric charges (ions and free electrons) and molecules with magnetic moments, which may contribute to magnetic field-induced changes in metabolite and macromolecule production, MF appears as a correction factor affecting lipid metabolism in the context of light and temperature effects. A potential link between MF and the effects on living organisms is due to its induced oxidative stress, which can alter the energy level and direction of electron spins, thereby increasing the activity, concentration and lifetime of free radicals. Magnetic fields were applied during the growth of different kinds of microorganisms and different results were found. In the related research of the microalgae magnetic biotechnology, the growth of the microalgae can be inhibited in the magnetic field intensity of more than 120mT, and the growth of the microalgae can be effectively promoted by 30 mT-60 mT. Due to the uniqueness of the experimental device, experimental studies are limited to a steady magnetic field and an alternating magnetic field. There is no further investigation regarding the magnetic field strength and magnetic field density for microalgae growth. The magnetic treatment has the advantages of low cost, convenient use, no toxicity, wide application range, no secondary pollutant and the like. The Magnetic Field (MF) can act on the metabolism of the microorganisms, its effect on cell growth and the response evaluated can be classified as inhibitory, stimulatory or ineffective depending on the form, intensity and time of application. Magnetic field strength, byproduct production and microbial growth occur at high and low intensities, and magnetic field is considered to be a potential physical treatment to promote cell growth and biosynthesis of microalgae. However, the existing technology lacks a microalgae photo-biological reaction system which has the advantages of simplified experimental steps, small device volume, less external interference factors, reduction of useless energy loss, capability of separating microalgae from magnetic particles and capability of secondarily utilizing the magnetic particles.

Disclosure of Invention

In view of the above technical problems, the present invention provides a novel photo-biological reaction system and method for culturing microalgae using a stable electromagnetic field, which provides a stable magnetic field in the growth cycle of microalgae, and can control the strength of the magnetic field at different growth stages of microalgae, so as to provide an optimal magnetic environment for growth at each stage, thereby increasing the yield of microalgae. The invention has the advantages of simplified experimental steps, small device volume, less external interference factors and reduced useless energy loss, and can realize the separation of microalgae and magnetic particles and realize the secondary utilization of the magnetic particles.

The technical scheme of the invention is as follows: a photo-biological reaction system for culturing microalgae by magnetic field coupling comprises a vertical tubular photo-biological reactor, an electromagnet, a first magnetic resistance plate, a second magnetic resistance plate, a rotating shaft, a rotating cylinder, a rotating platform, a top supporting plate, a base and a controller;

the top of the vertical tubular photobioreactor is provided with a first air inlet pipe and an air outlet pipe, and the bottom of the vertical tubular photobioreactor is provided with a second air inlet pipe; the periphery of the vertical tubular photobioreactor is surrounded by a first magnetic resistance plate and a second magnetic resistance plate, the first magnetic resistance plate and the second magnetic resistance plate are arranged on the base, the bottoms of the two opposite first magnetic resistance plates are respectively and rotatably connected with a rotating shaft on the base, and the electromagnets are uniformly arranged on the two first magnetic resistance plates; the bottom of the vertical tubular photobioreactor is placed in a through hole of a base, a rotating table is arranged below the base, and the rotating table can drive the base to rotate; the rotating cylinder is arranged on the top supporting plate and is connected with the top of the vertical tubular photobioreactor, and the rotating cylinder is used for lifting the vertical tubular photobioreactor out of the through hole of the base; the controller is respectively connected with the electromagnet, the rotary table and the rotary cylinder.

In the scheme, the device also comprises three transparent baffles; the middle of the three baffles is provided with a through hole, the three baffles are sequentially sleeved on the vertical tubular photobioreactor from top to bottom, the baffles are connected with the first magnetic resistance plate, the first magnetic resistance plate is provided with a clamping groove, the two ends of each baffle are respectively installed in the clamping grooves, and the space enclosed by the first magnetic resistance plate and the second magnetic resistance plate is divided into an upper region, a middle region and a lower region from top to bottom by the three baffles.

Further, the fluorescent screen is also included; the fluorescent plate is provided with a groove and is arranged on the baffle plate through the groove; the fluorescent plate is connected with the controller.

In the above scheme, the second magnetic resistance plate comprises a vertical plate; the two sides of the vertical plate are respectively provided with a sector plate, a sliding groove is formed behind the vertical plate, the bottom of the sector plate is installed on the sliding groove, one side of the sector plate is connected with the vertical plate, the other side of the sector plate is connected with the first magnetic resistance plate, and the first magnetic resistance plate is pulled open towards the two sides to drive the sector plate to unfold.

In the scheme, the vertical tubular photobioreactor is made of transparent materials, and the vertical photobioreactor is a transparent glass tube, so that the algae liquid in the tube can be uniformly irradiated by illumination and a magnetic field, and the illumination and the magnetic field are effectively utilized.

In the above scheme, the first air inlet pipe and the second air inlet pipe are respectively connected with the CO₂The gas cylinders are connected.

A culture method of a photo-biological reaction system for culturing microalgae by magnetic field coupling comprises the following steps:

step S1, adding the microalgae culture solution into a vertical tube type photobioreactor, wherein a first air inlet pipe and a second air inlet pipe of the vertical tube type photobioreactor and CO are respectively connected with a first air inlet pipe and a second air inlet pipe of the vertical tube type photobioreactor₂Connecting the gas cylinders;

step S2, measuring the optical density of the microalgae in the culture period of the microalgae to determine different growth stages of the microalgae;

step S3, opening a magnetic field coupling culture in the exponential phase and the stable phase of microalgae growth, wherein the magnetic field density in the area can be changed by adjusting the angle of the electromagnet;

step S4, after magnetic field coupling culture, turning off the magnetic field, and detecting the dry weight of the cells;

and step S5, separating the magnetic particles from the microalgae by using an electromagnetic field to realize secondary utilization of the magnetic particles, and weighing the cultured microalgae after centrifugal drying.

In the above scheme, the light-to-dark ratio in step S2 is 12: 12, the room temperature is 25 ℃, the intensity of the environmental magnetic field is measured by using a gaussmeter, the optical density of the sample is measured by using an optical density instrument in an ABS mode, and the growth time of the microalgae is in direct proportion to the optical density, so that the growth trend of the microalgae under the magnetic field condition is judged. The ambient magnetic field strength was measured using a gauss meter to confirm that the magnetic field strength was a stable value within the photobioreactor system.

In the scheme, the magnetic field intensity in the step S3 is 30-60 mT, the electromagnetic field is intermittently switched on, and the magnetic field culture time is controlled.

In the scheme, in the step S5, the rotating speed of the centrifugal machine is 4000-5000 rmp, the centrifugal machine is centrifuged for 10-15 min, and the dry weight of the microalgae is measured by drying in an oven at 60 ℃.

The upper and lower parts of the main pipeline of the invention are provided with the vent pipes, the gas introducing mode can be selected, the culture solution in the pipeline can slightly vibrate along with the floating of bubbles by selecting the bottom gas introducing mode, and microalgae is not easy to deposit, or the bottom of the reactor is not easy to deposit by connecting a long glass pipe to the bottom of the main pipeline from the upper gas introducing pipe.

The electromagnets and the fluorescent plates are arranged at intervals, vertical space is fully utilized, the vertical space corresponds to an upper area, a middle area and a lower area, and the microalgae growth concentration changes are compared in different areas in the microalgae culture stage.

The electromagnet can keep a constant magnetic field in the electrifying process, and can also be electrified with alternating current to form an alternating magnetic field, thereby providing a new direction in the aspect of researching microalgae culture.

The magnetic resistance plate is a black magnetic resistance plate, and reduces external light interference in order to prevent magnetic fields on two sides from offsetting each other with the outside.

The baffle is a transparent baffle, and illumination and a magnetic field with the same intensity are carried out on the upper, middle and lower three zones while microalgae is cultivated in a zone.

The periphery of the whole photo-biological reaction system is provided with magnetic resistance plates which are used for controlling the distribution of a magnetic field so as to prevent the difference of the internal and external strength of the magnetic field from being large.

Compared with the prior art, the invention has the beneficial effects that: the photo-biological reaction system provides a choice for a gas introduction mode: the method is not a single aeration mode any more, and microalgae deposition is considered, so that the microalgae is uniform in the culture solution. The photo-biological reaction system provides a feasible experimental device for people to research the influence of a magnetic field on the growth of microalgae in recent years. In a limited device space, the photobioreactor is reasonably divided into three areas, so that the microalgae growth trend can be judged more comprehensively and reasonably. When the electromagnetic field is added, the black magnetic resistance plate is added, so that the black magnetic resistance plate not only can reduce the interference of an external magnetic field on the electromagnetic field, but also can reduce the influence of external light on the growth of microalgae. The fluorescent plate can be freely converted into other colored light in the growth period of the microalgae, and the favorable conditions for the growth of the microalgae can be effectively utilized. The rotating platform is additionally arranged at the bottom of the magnetic field device, so that the magnetic field irradiation is uniform through rotating the electromagnet during microalgae cultivation. The rotating shaft is added between the baffles, and the influence of the magnetic field on the growth of the microalgae under the condition of different magnetic field densities can be explored by adjusting the inclination angle of the electromagnet without changing the illumination intensity and the illumination direction. The magnetic field intensity change in the microalgae growth cycle is satisfied: the optimal magnetic field intensity required by the microalgae in different growth stages is different, and the optimal magnetic field intensity for the microalgae in each stage can be explored through the photo-biological reaction device. In the process of studying the growth of the microalgae, not only a constant magnetic field can be used, but also the influence of an alternating magnetic field on the growth of the microalgae can be studied, and the magnetic field density of an area can be changed by adjusting the angle of the magnetic field; under the magnetic field condition, the microalgae culture duration can be automatically adjusted, and the duration under the optimal microalgae magnetic field condition is explored. The magnetic field device is switched on intermittently to reduce energy loss, and external energy consumption is reduced as far as possible while the growth of the microalgae is promoted. In the microalgae collecting stage, the magnetic flocculant can be used for realizing the effective recovery of the microalgae. The device can be used for separating microalgae from magnetic particles and realizing secondary utilization of the magnetic particles.

In conclusion, the influence of the magnetic field on the growth of the microalgae is comprehensively considered, and in order to better explore the optimal magnetic field intensity of the magnetic field at each stage of the growth cycle of the microalgae, the invention selects the ventilation path with the optimal effect. In a photo-generated system capable of adjusting the magnetic field, the experimental steps are simplified, the volume of the device is reduced, external interference factors are reduced, the time length of the magnetic field culture is effectively controlled, and the waste energy loss is effectively reduced. The magnetic field selection provides a new direction, and the regional culture can ensure the rigor of the experiment. The invention can be applied to the whole process of microalgae growth, including microalgae collection. The method can be applied to microalgae growth and recovery and reuse of magnetic particles in the flocculating agent, and can also be applied to pretreatment of a culture medium or other additives.

Drawings

FIG. 1 is a schematic view of a magnetic field photobioreactor system according to the present invention;

FIG. 2 is a cross-sectional view between a vertical tubular photobioreactor and a rotary stage;

FIG. 3 is a photobioreactor system with added rotating shaft.

In fig. 1, a first magnetic resistance plate, 2, a second magnetic resistance plate, 3, a vertical tubular photobioreactor, 4, a baffle plate, 5, a fluorescent plate, 6, an electromagnet, 7, a second air inlet pipeline, 8, a first air inlet pipeline, 9, an air outlet pipe, 10 and a rotating shaft; 11. the rotary air cylinder 12, the rotary table 13, the top support plate 14 and the base.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Fig. 1 to 3 show a preferred embodiment of the photobioreactor for cultivating microalgae by magnetic field coupling, which includes a vertical tubular photobioreactor 3, an electromagnet 6, a first magnetic resistance plate 1, a second magnetic resistance plate 2, a rotating shaft 10, a rotating cylinder 11, a rotating table 12, a top support plate 13, a base 14, and a controller.

The top of the vertical tubular photobioreactor 3 is provided with a first air inlet pipe 8 and an air outlet pipe 9, and the bottom is provided with a second air inlet pipe 7; the periphery of the vertical tubular photobioreactor 3 is surrounded by a first magnetic resistance plate 1 and a second magnetic resistance plate 2, the first magnetic resistance plate 1 and the second magnetic resistance plate 2 are installed on a base 14, the bottoms of two opposite first magnetic resistance plates 1 are respectively in rotating connection with a rotating shaft 10 on the base 14, and the electromagnets 6 are uniformly installed on the two first magnetic resistance plates 1; the bottom of the vertical tubular photobioreactor 3 is placed in a through hole of a base 14, a rotating platform 12 is arranged below the base 14, and the rotating platform 12 can drive the base 14 to rotate; the rotary cylinder 11 is arranged on the top supporting plate 13, the rotary cylinder 11 is connected with the top of the vertical tubular photobioreactor 3, and the rotary cylinder 11 is used for lifting the vertical tubular photobioreactor 3 out of the through hole of the base 14; the controller is respectively connected with the electromagnet 6, the rotating platform 12 and the rotating cylinder 11.

According to the present embodiment, it is preferable that three transparent baffles 4 are further included; the middle of three baffles 4 is provided with a through hole, the three baffles are sequentially sleeved on the vertical tubular photobioreactor 3 from top to bottom, the baffles 4 are connected with the first magnetic resistance plate 1, the first magnetic resistance plate 1 is provided with a clamping groove, two ends of the baffles 4 are respectively installed in the clamping groove, and the space enclosed by the first magnetic resistance plate 1 and the second magnetic resistance plate 2 is divided into an upper region, a middle region and a lower region from top to bottom by the three baffles 4. The top of the space enclosed by the first magnetic resistance plate 1 and the second magnetic resistance plate 2 is provided with a magnetic resistance cover plate.

According to the present embodiment, it is preferable that a fluorescent plate 5 is further included; the fluorescent plate 5 is provided with a groove and is arranged on the baffle 4 through the groove; the phosphor plate 5 is connected to the controller.

According to the present embodiment, preferably, the second magnetic resistance plate 2 includes a vertical plate; the both sides of vertical board are equipped with the sector plate respectively, are equipped with the spout behind vertical board 2, and the bottom of sector plate is installed on the spout, and one side and the vertical board of sector plate are connected, and the opposite side is connected with first magnetic resistance board 1, and first magnetic resistance board 1 pulls open to both sides, drives the sector plate and expandes.

According to the embodiment, preferably, the vertical tubular photobioreactor 3 is made of transparent materials, and the vertical photobioreactor is made of transparent glass tubes, so that the algae liquid in the tubes can be uniformly irradiated by light and a magnetic field, and the light and the magnetic field can be effectively utilized.

According to the present embodiment, preferably, the first and second intake pipes 8 and 7 are connected to CO, respectively₂The gas cylinders are connected.

A culture method of a photo-biological reaction system for culturing microalgae by magnetic field coupling comprises the following steps:

step S1, adding the microalgae culture solution into the vertical pipe type photobioreactor 3, wherein the first air inlet pipe 8 and the second air inlet pipe 7 of the vertical pipe type photobioreactor 3 are respectively communicated with CO₂Connecting the gas cylinders;

step S2, measuring the optical density of the microalgae in the culture period of the microalgae to determine different growth stages of the microalgae;

step S3, opening a magnetic field coupling culture in the exponential phase and the stable phase of microalgae growth, wherein the magnetic field intensity of a region can be changed by adjusting the angle of the electromagnet 6;

step S4, after magnetic field coupling culture, turning off the magnetic field, and detecting the dry weight of the cells;

and step S5, separating the magnetic particles from the microalgae by using an electromagnetic field to realize secondary utilization of the magnetic particles, and weighing the cultured microalgae after centrifugal drying.

According to this embodiment, preferably, the light-to-dark ratio in step S2 is 12: 12, the room temperature is 25 ℃, the intensity of the environmental magnetic field is measured by using a gaussmeter, the optical density of the sample is measured by using an optical density instrument in an ABS mode, and the growth time of the microalgae is in direct proportion to the optical density, so that the growth trend of the microalgae under the magnetic field condition is judged. The ambient magnetic field strength was measured using a gauss meter to confirm that the magnetic field strength was a stable value within the photobioreactor system.

According to the embodiment, preferably, in the step S3, the magnetic field intensity is 30-60 mT, the electromagnetic field is intermittently turned on for 1-4 hours every day, and the magnetic field culture time is controlled.

According to the present embodiment, preferably, in the step S5, the rotation speed of the centrifuge is 4000 to 5000rmp, the centrifugation is performed for 10 to 15min, and the dry weight of the microalgae is determined by drying in an oven at 60 ℃.

Adding appropriate amount of water, algae seeds and microalgae culture medium (such as BG11 culture medium) into the vertical tubular photobioreactor 3, and introducing CO into the vertical tubular photobioreactor 3 through a first air inlet pipe 8 or a second air inlet pipe 7₂The fluorescent plate 5 provides illumination required by microalgae growth, and the ratio of day to night is 1: 1, the microalgae can grow normally in similar growth environments.

The vertical tubular photobioreactor 3 is divided into an upper culture area, a middle culture area and a lower culture area by the baffle 4, and the deposition of microalgae on the bottom 3 of the tubular photobioreactor is reduced while introducing gas, so that the algae liquid is uniform in the photobioreactor in a growth period;

the electromagnet 6 can adjust the interference duration and the magnetic field intensity in the growth period of the microalgae, not only can the constant magnetic field interfere the growth environment of the microalgae, but also can alternate the magnetic field to further study the growth of the microalgae in the growth period, the optimal growth magnetic field intensity required by the microalgae is changed correspondingly to different growth stages of the microalgae, and the electric magnetic field intensity is adjusted by the electromagnet 6;

the surrounding black first magnetic resistance plate 1 and the second magnetic resistance plate 2 can reduce the influence of external illumination on the growth of microalgae, and can also reduce the interference of an external magnetic field on an electromagnetic field;

as shown in FIG. 1, a proper amount of water, algal species and microalgae culture medium, such as BG11 culture medium, is added into a vertical tubular photobioreactor 3, and CO is introduced into the tubular photobioreactor through a first gas inlet pipe 8 and a second gas inlet pipe 7₂The fluorescent plate 5 provides illumination required by microalgae growth, and the ratio of day to night is 1: 1, the microalgae can normally grow in a similar growth environment; the vertical tubular photobioreactor 3 is divided into an upper culture area, a middle culture area and a lower culture area by the baffle 4, and the deposition of microalgae on the bottom 3 of the tubular photobioreactor is reduced while introducing gas, so that the algae liquid is uniform in the photobioreactor in a growth period; the electromagnet 6 can adjust the interference duration and the magnetic field intensity in the growth period of the microalgae, not only the constant magnetic field interferes the growth environment of the microalgae, but also the alternating magnetic field can be used for further research on the growth of the microalgae in the growth period, the optimal growth magnetic field intensity required by the microalgae is changed along with the change of the electromagnetic field intensity corresponding to different growth stages of the microalgae, and the electric magnetic field intensity is adjusted by the electromagnet 6; the surrounding black first magnetic resistance plate 1 and the second magnetic resistance plate 2 can reduce the influence of external illumination on the growth of microalgae, and can also reduce the interference of an external magnetic field on an electromagnetic field; the fluorescent plate 5 changes the color of visible light in the growth period of microalgae, and the visible light is fully utilized under the condition that the black magnetic resistance plate is fixed on the periphery.

As shown in fig. 2, a rotating platform 12 and a support base 14 of a photobioreactor are added to the bottom of the device shown in fig. 1, an electromagnetic field is turned on when the growth of microalgae starts, a magnetic field is used for culturing the micro-strandard algae every day, the rotating platform 12 is arranged below the device when the magnetic field is turned on, the rotating platform rotates at a set rotating speed, magnetic field interference is carried out during the illumination period, the interference duration is set, and the magnetic field interference is stopped when the microalgae enters the growth stabilization period, so that the algae liquid can be uniformly radiated by the magnetic field.

As shown in fig. 3, the inclination angle of the first magnetic resistance plate 1 is changed by the rotating shaft 10, so as to change the magnetic field density inside the photobioreactor, and the growth tendency of microalgae under different magnetic field densities can be explored.

Specifically, the method for culturing the photo-biological reaction system of the microalgae by using the magnetic field comprises the following steps:

step S1, adding microalgae culture solution (culture medium can be BG11) into vertical tubular photobioreactor 3, containing 1.5% CO₂The sterile filtered air enters the vertical tubular photobioreactor 3 through a top first air inlet pipe 8 or a bottom and second air inlet pipe 7 at a flow rate of 0.2 vvm;

step S2, culturing microalgae by a conventional method, and measuring optical density of 10ml of algae solution after 0, 1, 3, 5 and 7 days to determine the growth stage of the microalgae;

step S3, when the growth stage of the microalgae is determined to be logarithmic phase and stable phase, intermittently turning on a magnetic field device for 1-4 hours every day, and automatically adjusting the current after adding the magnetic field to control the magnetic field intensity of the area;

step S4, judging the growth trend of microalgae through CDW;

and step S5, centrifuging at 3000-4000 rpm after the microalgae growth cycle is finished, and measuring the total yield.

FIG. 2 is a cross-sectional view of a vertical tubular photobioreactor, in which a first gas inlet pipe 8 extends vertically to the bottom and does not contact the bottom of the reactor, and a second gas inlet pipe 7 disperses microalgae deposition by gas flow to make the algae solution uniform.

Example 1:

a culture method of a photo-biological reaction system for culturing microalgae by using a magnetic field comprises the following steps:

step S1, adding 600mL of chlorella culture solution (BG11) into the vertical tube type photobioreactor 3, and introducing CO₂Gas cylinder, CO₂At 0.02vvm, the phosphor plate is turned on, the light dark period 12: 12, room temperature is 25 ℃;

step S2, culturing chlorella according to the conditions in S1 in a culture period, and sampling for 0, 1, 3, 5 and 7 days to determine the optical density of the chlorella so as to determine the growth stage of the chlorella;

step S3, starting to open an electromagnetic field in the growth exponential phase of the chlorella, culturing the chlorella at the magnetic field intensity of 30MT every day, carrying out magnetic field interference in the illumination period for 1h, and stopping the magnetic field interference when the chlorella enters the stabilization period;

step S4, after the chlorella reaches the exponential phase and the stable phase of growth, vacuum filtering 10mL culture by pre-weighed filter paper to determine, drying in an oven at 80 ℃ to determine CDW (dry cell weight);

and S5, after the growth period is finished, centrifuging at 3000-4000 rpm for 10-15 min, drying in an oven at 60 ℃, and weighing.

Example 2:

a culture method of a photo-biological reaction system for culturing microalgae by using a magnetic field comprises the following steps:

step S1, adding 600mL of the Inula confusa culture solution (BG11) into the vertical tube type photobioreactor 3, and introducing CO₂Gas cylinder, CO₂At 0.02vvm, the phosphor plate is turned on, the light dark period 12: 12, room temperature is 25 ℃;

step S2, culturing the Ascophyllum nodosum according to the conditions in the step S1 in a culture period, and sampling for measuring the optical density of the Ascophyllum nodosum in 0, 1, 3, 5 and 7 days to determine the growth stage of the Ascophyllum nodosum;

step S3, starting to turn on an electromagnetic field in the stable period of the Inula palustris, culturing the Inula palustris with the magnetic field intensity of 40mT every day, turning a rotary table 12 below when the tool is turned on the magnetic field at 36 degrees/min, performing magnetic field interference during illumination, wherein the interference time is 1.5h, and stopping the magnetic field interference when the Inula palustris enters the stable period of growth;

step S4, determining when the at-a-mosla has reached the exponential phase of growth and after the stationary phase, by vacuum-filtering 10mL of culture through pre-weighed filter paper, drying in an oven at 80 ℃ to determine CDW (dry cell weight);

and S5, after the growth period is finished, centrifuging at 3000-4000 rpm for 10-15 min, drying in an oven at 60 ℃, and weighing.

Example 3:

a culture method of a photo-biological reaction system for culturing microalgae by using a magnetic field comprises the following steps:

step S1, adding 600mL of Scenedesmus obliquus culture solution (BG11) into the vertical tube type photobioreactor 3, and introducing CO₂Gas cylinder, CO₂At 0.02vvm, the phosphor plate is turned on, the light dark period 12: 12, room temperature is 25 ℃;

step S2, culturing Scenedesmus obliquus according to the conditions in the step S1 in a culture period, and sampling and measuring optical density of the Scenedesmus obliquus in 0, 1, 3, 5 and 7 days to determine the growth stage of the Pythium aphanidermatum;

step S3, starting to open an electromagnetic field in the stable period of the scenedesmus obliquus, culturing the scenedesmus obliquus with the magnetic field intensity of 40mT every day, performing magnetic field interference in the illumination period for 1.5h, and stopping the magnetic field interference when the Microsantha angustifolia enters the stable period;

step S4, after the Scenedesmus obliquus reaches the exponential phase and the stable phase of growth, performing vacuum filtration on 10mL of culture through pre-weighed filter paper to determine, and drying in an oven at 80 ℃ to determine CDW (cell dry weight);

step S6, after the growth period is finished, preparing a magnetic flocculant, dissolving 26mmol of ferric chloride hexahydrate and 13mmol of ferric chloride tetrahydrate in 125mL of distilled water, heating at 80 ℃ for 30min under a nitrogen environment, adding 8.4mL of 25% ammonium hydroxide, keeping for 30min, cooling to room temperature, performing magnetic decantation on nano Fe by using distilled water and ethanol₃O₄Washing is carried out, and the silica is coated with Fe3O4 by hydrolysis of tetraethyl orthosilicate (TEOS, Si)₃O₄The nanoparticles were added to a mixture of 200 ml ethanol, 30 ml distilled water, 3 ml ammonium hydroxide solution and 60 mmol TEOS. The resulting mixture was shaken at room temperature for 12 hours. After washing with ethanol, Fe was finally carried out by reaction with triethoxysilane (APTES), and Octyltriethoxysilane (OTES)₃O₄@ organosilane functionalization of silica nanoparticles, addition of triethoxysilane and octyltriethoxysilane to Fe₃O₄@ ethanol suspension. The total concentration of triethoxysilane and octyltriethoxysilane was 35 mol/L. After the ultrasonic treatment, the mixture was shaken for 12 hours and washed with ethanol, whereby bifunctional Fe could be obtained₃O₄Magnetic nanoparticle flocculant. Adding into the algae solution after finishing growth, opening the electromagnet 6 on one side after flocculation is finished, and separating the magnetic nano-flocculant adsorbed on the microalgae by using the electromagnet 6.

In this embodiment 3, the device can utilize the magnetic field during the growth of the microalgae, extract and separate the microalgae by using the magnetic nano-flocculant, and separate the magnetic nano-particles by using the electromagnetic field after the extraction is completed for recycling.

Example 4:

a culture method of a photo-biological reaction system for culturing microalgae by using a magnetic field comprises the following steps:

step S1, adding 600mL of chlorella culture solution (BG11) into the vertical tube type photobioreactor 3, and introducing CO₂Gas cylinder, CO₂At 0.02vvm, the phosphor plate is turned on, the light dark period 12: 12, room temperature 25 ℃. Adjusting the inclination angle of the first magnetism resisting plate 1 to be 30 degrees, adjusting the angle of the fluorescent plate 5, and still keeping vertical irradiation on the vertical tubular photobioreactor 3;

step S2, culturing Chlorella under the conditions of step S1 in a culture period, and sampling for 0, 1, 3, 5 and 7 days to determine the optical density of Chlorella to determine the growth stage of Chlorella;

step S3, starting to open an electromagnetic field in the stable period of the chlorella, culturing the chlorella at the magnetic field intensity of 30MT every day, carrying out magnetic field interference in the illumination period for 1h, and stopping the magnetic field interference when the chlorella enters the stable period;

step S4, after the chlorella reaches the exponential phase and the stationary phase of growth, it is measured by vacuum filtering 10mL of culture through pre-weighed filter paper, and drying in an oven at 80 ℃ to measure CDW (dry cell weight).

The above embodiments are only used for illustrating the design idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.