Method for heterotrophic culture of high-yield protein from chlorella

Abstract

The invention relates to the technical field of biology, and discloses a method for heterotrophic culture of chlorella to produce high-yield protein, which comprises the following steps: S1, preparation of a seed solution; s2, preparing a heterotrophic culture medium; s3, optimization of culture conditions; s4, a heterotrophic culture process; s5, performing online monitoring and feedback control; s6, monitoring and adjusting the culture process; s7, harvesting and cell disruption; s8, protein extraction and purification; and S9, freeze drying. According to the method for heterotrophic culture of the chlorella to produce the high-yield protein, the chlorella is cultured in a bioreactor, an accurately prepared culture medium and strictly controlled culture conditions including temperature, stirring rate and ventilation rate are used, and the culture mode allows the chlorella to grow in a stable environment which is not limited by natural illumination and weather conditions; and meanwhile, through real-time data tracking and automatic parameter adjustment of the online monitoring and feedback control system, the culture conditions are further optimized, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, in particular to a method for heterotrophic cultivation of Chlorella to produce high protein. Background Art

[0002] Chlorella is a single-cell green microalgae, known for its amazing growth rate and efficient photosynthesis. They are widely distributed in nature, especially in nutrient-rich water bodies. Chlorella cells are rich in nutrients, especially protein, which can account for more than 50% of the cell dry weight, making it a potential source of high-quality protein.

[0003] However, the traditional method of cultivating Chlorella using photosynthesis, although it can use solar energy for energy conversion, is also limited by a variety of environmental factors, which directly affect the growth rate and protein production of Chlorella. Therefore, we proposed a method for heterotrophic cultivation of Chlorella to produce high protein. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for heterotrophic cultivation of Chlorella with high protein yield, which has the advantages of significantly improving the protein yield and production efficiency of Chlorella by precisely controlling the culture medium components, culture conditions and processes, while reducing environmental dependence and production costs. It solves the problem that the traditional Chlorella cultivation method using photosynthesis can use solar energy for energy conversion but is also limited by various environmental factors, which directly affect the growth rate and protein yield of Chlorella.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose of significantly improving the protein yield and production efficiency of Chlorella by precisely controlling the culture medium components, culture conditions and processes, while reducing environmental dependence and production costs, the present invention provides the following technical solution: A method for heterotrophic culture of Chlorella to produce high protein, comprising the following steps:

[0008] S1. Preparation of seed solution: Select a high-protein-producing Chlorella strain with high protein synthesis ability, and perform genetic screening to ensure its performance. The screened Chlorella is inoculated into BG-11 seed culture medium and cultured in a constant temperature shaker for 72 hours.

[0009] S2. Preparation of heterotrophic medium: Prepare heterotrophic medium with 40 g / L glucose as the main carbon source, 4 g / L of complex nitrogen source, 1 g / L of K2HPO4 as the phosphorus source, and 0.5 g / L of yeast extract to provide the necessary growth factors, and adjust the initial pH to 6.8;

[0010] S3. Optimization of culture conditions: Culture was carried out in a bioreactor with the temperature strictly controlled at 26°C, the stirring rate set to 300 rpm, and the aeration rate adjusted to 1.0 vvm;

[0011] S4, heterotrophic culture process: inoculating the seed solution with a 10% inoculation amount into the heterotrophic culture medium, and culturing in the bioreactor to maintain the culture conditions;

[0012] S5, online monitoring and feedback control: Introduce online biomass monitoring sensors, automatic pH controllers and dissolved oxygen (DO) detectors, use data analysis software to track carbon source consumption and protein synthesis rate in real time, and automatically adjust culture parameters through feedback control systems;

[0013] S6. Monitoring and adjustment of the culture process: real-time monitoring of key indicators in the culture process, and timely adjustment of stirring rate, ventilation volume and temperature according to monitoring data to optimize culture conditions;

[0014] S7. Harvesting and cell disruption: After reaching the predetermined culture time, the Chlorella cells are collected using a centrifuge, and the cell walls are broken by a high-pressure homogenizer or ultrasonic technology to release the protein;

[0015] S8. Protein extraction and purification: Cell debris is removed by centrifugation and filtration to obtain the protein-containing supernatant, which is then further purified using chromatography and dialysis.

[0016] S9. Freeze drying: freeze-dry the purified protein solution at -40°C for 24 hours to obtain protein powder.

[0017] Preferably, the ingredients of BG-11 seed culture medium include 1.5 g / L sodium nitrate, 0.04 g / L potassium dihydrogen phosphate, 0.075 g / L magnesium sulfate heptahydrate, 0.036 g / L calcium chloride dihydrate, 0.006 g / L citric acid, 0.006 g / L ferric ammonium citrate, 0.001 g / L ethylenediaminetetraacetic acid (EDTA), 0.0222 g / L zinc sulfate heptahydrate, 0.0144 g / L manganese chloride tetrahydrate, 0.0074 g / L molybdic acid, 0.0008 g / L copper sulfate pentahydrate and 0.0049 g / L cobalt nitrate hexahydrate.

[0018] Preferably, during the preparation of the BG-11 seed culture medium, all components must be sterilized by filtration through a 0.22 μm microporous filter membrane before use to ensure a sterile environment during the culture process.

[0019] Preferably, the temperature of the thermostatic shaker is set to 25±1° C., the light intensity is 2000 Lux, and the photoperiod is 12 hours of light / 12 hours of darkness.

[0020] Preferably, when culturing in a bioreactor, a combination of batch and continuous culture is adopted, with batch culture being adopted in the initial stage and switching to continuous culture mode 24 hours after inoculation to achieve rapid start-up and stable maintenance of Chlorella growth, and in the continuous culture mode the flow rate is controlled at 0.1 times the volume / day to match the discharge rate to maintain a constant cell density.

[0021] Preferably, the online biomass monitoring sensor is a densitometer, which estimates biomass by measuring the scattering or absorption of light of a specific wavelength by the culture solution. The measurement range of the densitometer is 0-4 OD units, the accuracy is ±0.001 OD units, and the real-time data update frequency is 1 minute / time.

[0022] Preferably, the automatic pH controller includes a pH electrode, a control system, an acid-base regulator storage tank and a precision metering pump, and monitors the pH value of the culture solution in real time through the pH sensitive electrode, and adjusts the addition of acid-base solution through the acid-base regulator storage tank and the precision metering pump to maintain a constant pH value.

[0023] Preferably, the dissolved oxygen (DO) detector comprises an oxygen-sensitive fluorescent material, a light source, a photodetector and a signal processing unit. The optical dissolved oxygen detector measures the dissolved oxygen concentration by utilizing the absorption characteristics of oxygen molecules to light of a specific wavelength.

[0024] Preferably, the data analysis software has a data acquisition interface, based on a real-time data processing algorithm, has a chart generation function, and supports historical data query and analysis; the feedback control system has a communication interface with the bioreactor control system, and based on preset culture conditions, including pH and DO levels, through a PID control algorithm, it can automatically adjust the actuators, including regulating valves and frequency converters.

[0025] Preferably, when using a centrifuge to collect Chlorella cells, the rotation speed is set to 3000 rpm and the duration is 20 minutes.

[0026] (III) Beneficial effects

[0027] Compared with the prior art, the present invention provides a method for heterotrophic cultivation of Chlorella to produce high-yield protein, which has the following beneficial effects:

[0028] 1. The method for heterotrophically culturing Chlorella to produce high-yield protein, wherein the Chlorella is cultured in a bioreactor using a precisely formulated culture medium and strictly controlled culture conditions, including temperature, stirring rate, and aeration rate. This culture method allows the Chlorella to grow in a stable environment that is not restricted by natural light and climatic conditions, thereby significantly increasing protein production. At the same time, through real-time data tracking and automatic parameter adjustment of an online monitoring and feedback control system, the culture conditions are further optimized and production efficiency is improved.

[0029] 2. The method for heterotrophic cultivation of Chlorella to produce high-yield protein. The heterotrophic cultivation method reduces the dependence on natural light and climatic conditions through artificially controlled environmental conditions, making the production process more stable and controllable. The application of online monitoring and feedback control systems allows the cultivation parameters to be automatically adjusted according to real-time data, reducing resource waste, improving the conversion efficiency of raw materials, and thus reducing production costs. In addition, through precise control of cultivation conditions and subsequent protein extraction and purification processes, the high purity and high quality of the protein product are ensured, thereby improving the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic flow chart of the method for heterotrophic cultivation of Chlorella for high protein production. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1 , a method for heterotrophic cultivation of Chlorella to produce high protein, comprising the following steps:

[0033] S1. Preparation of seed solution: Select a high-protein-producing Chlorella strain with high protein synthesis ability, and perform genetic screening to ensure its performance. The screened Chlorella is inoculated into BG-11 seed culture medium and cultured in a constant temperature shaker for 72 hours.

[0034] S2. Preparation of heterotrophic medium: Prepare heterotrophic medium with 40 g / L glucose as the main carbon source, 4 g / L of complex nitrogen source, 1 g / L of K2HPO4 as the phosphorus source, and 0.5 g / L of yeast extract to provide the necessary growth factors, and adjust the initial pH to 6.8;

[0035] S3. Optimization of culture conditions: Culture was carried out in a bioreactor with the temperature strictly controlled at 26°C, the stirring rate set to 300 rpm, and the aeration rate adjusted to 1.0 vvm;

[0036] S4, heterotrophic culture process: inoculating the seed solution with a 10% inoculation amount into the heterotrophic culture medium, and culturing in the bioreactor to maintain the culture conditions;

[0037] S5, online monitoring and feedback control: Introduce online biomass monitoring sensors, automatic pH controllers and dissolved oxygen (DO) detectors, use data analysis software to track carbon source consumption and protein synthesis rate in real time, and automatically adjust culture parameters through feedback control systems;

[0038] S6. Monitoring and adjustment of the culture process: real-time monitoring of key indicators in the culture process, and timely adjustment of stirring rate, ventilation volume and temperature according to monitoring data to optimize culture conditions;

[0039] S7. Harvesting and cell disruption: After reaching the predetermined culture time, the Chlorella cells are collected using a centrifuge, and the cell walls are broken by a high-pressure homogenizer or ultrasonic technology to release the protein;

[0040] S8. Protein extraction and purification: Cell debris is removed by centrifugation and filtration to obtain the protein-containing supernatant, which is then further purified using chromatography and dialysis.

[0041] S9. Freeze drying: freeze-dry the purified protein solution at -40°C for 24 hours to obtain protein powder.

[0042] Further, the components of the BG-11 seed culture medium include 1.5 g / L sodium nitrate, 0.04 g / L potassium dihydrogen phosphate, 0.075 g / L magnesium sulfate heptahydrate, 0.036 g / L calcium chloride dihydrate, 0.006 g / L citric acid, 0.006 g / L ferric ammonium citrate, 0.001 g / L ethylenediaminetetraacetic acid (EDTA), 0.0222 g / L zinc sulfate heptahydrate, 0.0144 g / L manganese chloride tetrahydrate, 0.0074 g / L molybdic acid, 0.0008 g / L copper sulfate pentahydrate and 0.0049 g / L cobalt nitrate hexahydrate.

[0043] Specifically, sodium nitrate, as the main nitrogen source, provides the nitrogen required for the synthesis of amino acids and nucleic acids; potassium dihydrogen phosphate supplements phosphorus and potassium, which are essential for cellular energy metabolism and enzyme activity; magnesium sulfate and calcium chloride provide magnesium and calcium, respectively. Magnesium is the central element of chlorophyll, while calcium is involved in cell signal transduction and cell wall stability; citric acid and ferric ammonium citrate provide iron, which is an essential cofactor for many biological enzymes. Citric acid helps the absorption of iron; ethylenediaminetetraacetic acid (EDTA) acts as a metal ion chelator, which helps prevent oxidative stress caused by metal ions; zinc sulfate, manganese chloride, molybdic acid, copper sulfate and cobalt nitrate hexahydrate provide trace elements such as zinc, manganese, molybdenum, copper and cobalt, which are essential for the metabolic pathways and enzyme activity of Chlorella. Overall, these components of BG-11 seed culture medium work together to provide Chlorella with a nutrient-rich and balanced growth environment.

[0044] Furthermore, during the preparation of the BG-11 seed culture medium, all components must be sterilized by filtration through a 0.22 μm microporous filter membrane before use to ensure a sterile environment during the culture process.

[0045] Specifically, the BG-11 seed culture medium that is sterilized by filtration through a 0.22 μm microporous filter membrane provides a clean, safe and nutrient-rich growth environment for Chlorella, which is one of the key steps to achieve efficient heterotrophic culture and high protein yield.

[0046] Furthermore, the temperature of the thermostatic shaker was set at 25 ± 1 °C, the light intensity was 2000 Lux, and the photoperiod was 12 h light / 12 h dark.

[0047] Specifically, the constant temperature shaker plays a vital role in the preparation process of Chlorella seed liquid. Its temperature is set at 25±1℃, ensuring the optimal temperature conditions for the growth of Chlorella. This temperature range is close to the natural growth temperature of Chlorella, which is conducive to its metabolic activities and maximization of growth rate. The light intensity is set to 2000Lux, providing suitable lighting conditions, promoting the photosynthesis of Chlorella, and helping to synthesize more organic matter and energy, thereby supporting protein synthesis. The light cycle is 12 hours of light / 12 hours of darkness, simulating the day and night alternation in nature. This periodic light and dark cycle has a regulatory effect on the biological clock and metabolic rhythm of Chlorella, helping to maintain its normal physiological functions and growth cycle.

[0048] Furthermore, when culturing in a bioreactor, a combination of batch and continuous culture is adopted. Batch culture is adopted in the initial stage, and the continuous culture mode is switched to 24 hours after inoculation to achieve rapid start-up and stable maintenance of the growth of Chlorella. In the continuous culture mode, the flow acceleration rate is controlled at 0.1 times the volume / day to match the discharge rate to maintain a constant cell density.

[0049] Specifically, batch culture provides a stable and controllable environment, which is conducive to the initial growth and development of Chlorella, while switching to continuous culture mode helps to stably maintain the growth state of Chlorella and ensure the continuity and efficiency of the culture process. In the continuous culture mode, by controlling the flow acceleration rate at 0.1 times the volume / day and matching it with the discharge rate, a constant cell density can be effectively maintained, thereby maintaining the stability and consistency of Chlorella growth.

[0050] Furthermore, the online biomass monitoring sensor is a densitometer, which estimates biomass by measuring the scattering or absorption of light of a specific wavelength by the culture medium. The measurement range of the densitometer is 0-4OD units, the accuracy is ±0.001OD units, and the real-time data update frequency is 1 minute / time.

[0051] Specifically, the optical densitometer can estimate the biomass of Chlorella in real time by measuring the scattering or absorption of light of a specific wavelength by the culture medium. This monitoring method is not only easy to operate, but also can provide continuous and real-time biomass data, which is of great significance for evaluating the growth status of Chlorella and adjusting the culture conditions.

[0052] Furthermore, the automatic pH controller includes a pH electrode, a control system, an acid-base regulator storage tank and a precision metering pump, which monitors the pH value of the culture solution in real time through the pH sensitive electrode, and adjusts the addition of acid-base solution through the acid-base regulator storage tank and the precision metering pump to maintain a constant pH value.

[0053] Specifically, the pH electrode serves as a sensor that can monitor the pH value of the culture solution in real time and transmit the data to the control system. The control system automatically adjusts the amount of acid-base regulator added according to the preset pH value range, and achieves precise control of the pH value of the culture solution through a precise metering pump. The high-precision monitoring of the pH electrode and the precise adjustment of the control system can ensure the stability of the pH value and avoid the adverse effects of pH fluctuations on the growth of Chlorella. The real-time monitoring and adjustment capabilities enable the pH value to respond quickly to environmental changes and maintain consistency in culture conditions.

[0054] Furthermore, the dissolved oxygen (DO) detector includes an oxygen-sensitive fluorescent material, a light source, a photodetector and a signal processing unit. The optical dissolved oxygen detector uses the absorption characteristics of oxygen molecules to light of a specific wavelength to measure the dissolved oxygen concentration.

[0055] Specifically, through the sensitive response of fluorescent materials to dissolved oxygen, the detector can provide accurate dissolved oxygen concentration data, which is crucial for evaluating and maintaining the optimal oxygen level required for the growth of Chlorella. The detector can monitor the dissolved oxygen level in real time to ensure timely response to changes in the demand for oxygen in the metabolism of Chlorella, and avoid affecting its growth and metabolic activities due to insufficient dissolved oxygen. The introduction of dissolved oxygen detectors not only improves the control accuracy of dissolved oxygen levels during the heterotrophic cultivation of Chlorella, but also helps to optimize the culture conditions and improve the growth efficiency and protein yield of Chlorella. It is one of the key technologies to achieve efficient and stable production.

[0056] Furthermore, the data analysis software has a data acquisition interface, based on a real-time data processing algorithm, with a chart generation function, and supports historical data query and analysis; the feedback control system has a communication interface with the bioreactor control system, and based on preset culture conditions, including pH and DO levels, through a PID control algorithm, it can automatically adjust the actuators, including regulating valves and frequency converters.

[0057] Specifically, based on real-time data, the data analysis software uses efficient data processing algorithms, which can not only generate intuitive charts to help operators quickly grasp the status of the culture process, but also support the query and in-depth analysis of historical data, making the optimization of the production process and problem diagnosis more convenient. In addition, the feedback control system is closely linked to the control system of the bioreactor. This automated adjustment mechanism ensures the accuracy and stability of the culture conditions, reduces the need for human intervention, and improves production efficiency and repeatability.

[0058] Further, when using a centrifuge to collect Chlorella cells, the rotation speed is set to 3000 rpm and the duration is 20 minutes.

[0059] In summary, the method for heterotrophic cultivation of Chlorella for high protein production is that Chlorella is cultivated in a bioreactor through a heterotrophic cultivation method, using a precisely formulated culture medium and strictly controlled culture conditions, including temperature, stirring rate and aeration rate. This cultivation method allows Chlorella to grow in a stable environment that is not restricted by natural light and climatic conditions, thereby significantly increasing the protein yield. At the same time, through real-time data tracking and automatic parameter adjustment of an online monitoring and feedback control system, the culture conditions are further optimized and the production efficiency is improved.

[0060] In addition, the method for heterotrophic cultivation of Chlorella to produce high-yield protein reduces dependence on natural light and climatic conditions through artificially controlled environmental conditions, making the production process more stable and controllable. The application of online monitoring and feedback control systems allows automatic adjustment of cultivation parameters according to real-time data, reduces resource waste, improves raw material conversion efficiency, and thus reduces production costs. In addition, precise control of cultivation conditions and subsequent protein extraction and purification processes ensure high purity and high quality of protein products, improves product market competitiveness, and solves the problem that the traditional Chlorella cultivation method using photosynthesis can use solar energy for energy conversion but is also limited by a variety of environmental factors, which directly affect the growth rate and protein yield of Chlorella.

[0061] The relevant modules involved in this system are all hardware system modules or functional modules that combine computer software programs or protocols with hardware in the prior art. The computer software programs or protocols involved in the functional modules are themselves technologies that are well known to those skilled in the art and are not improvements of this system. The improvements of this system are the interaction or connection relationships between the modules, that is, improvements to the overall structure of the system to solve the corresponding technical problems to be solved by this system.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for heterotrophic cultivation of Chlorella to produce high protein yield, characterized in that: The following steps are involved: S1. Preparation of seed solution: Select a high-protein-producing Chlorella strain with high protein synthesis ability, and perform genetic screening to ensure its performance. The screened Chlorella is inoculated into BG-11 seed culture medium and cultured in a constant temperature shaker for 72 hours. S2. Preparation of heterotrophic medium: Prepare heterotrophic medium with 40 g / L glucose as the main carbon source, 4 g / L of complex nitrogen source, 1 g / L of K2HPO4 as the phosphorus source, and 0.5 g / L of yeast extract to provide the necessary growth factors, and adjust the initial pH to 6.8; S3. Optimization of culture conditions: Culture was carried out in a bioreactor with the temperature strictly controlled at 26°C, the stirring rate set to 300 rpm, and the aeration rate adjusted to 1.0 vvm; S4, heterotrophic culture process: inoculating the seed solution with a 10% inoculation amount into the heterotrophic culture medium, and culturing in the bioreactor to maintain the culture conditions; S5, online monitoring and feedback control: Introduce online biomass monitoring sensors, automatic pH controllers and dissolved oxygen (DO) detectors, use data analysis software to track carbon source consumption and protein synthesis rate in real time, and automatically adjust culture parameters through feedback control systems; S6. Monitoring and adjustment of the culture process: real-time monitoring of key indicators in the culture process, and timely adjustment of stirring rate, ventilation volume and temperature according to monitoring data to optimize culture conditions; S7. Harvesting and cell disruption: After reaching the predetermined culture time, the Chlorella cells are collected using a centrifuge, and the cell walls are broken by a high-pressure homogenizer or ultrasonic technology to release the protein; S8. Protein extraction and purification: Cell debris is removed by centrifugation and filtration to obtain the protein-containing supernatant, which is then further purified using chromatography and dialysis. S9. Freeze drying: freeze-dry the purified protein solution at -40°C for 24 hours to obtain protein powder.

2. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: The components of the S1, BG-11 seed culture medium include 1.5 g / L sodium nitrate, 0.04 g / L potassium dihydrogen phosphate, 0.075 g / L magnesium sulfate heptahydrate, 0.036 g / L calcium chloride dihydrate, 0.006 g / L citric acid, 0.006 g / L ferric ammonium citrate, 0.001 g / L ethylenediaminetetraacetic acid (EDTA), 0.0222 g / L zinc sulfate heptahydrate, 0.0144 g / L manganese chloride tetrahydrate, 0.0074 g / L molybdic acid, 0.0008 g / L copper sulfate pentahydrate and 0.0049 g / L cobalt nitrate hexahydrate.

3. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 2, characterized in that: During the preparation of the BG-11 seed culture medium, all components must be sterilized by filtration through a 0.22 μm microporous filter membrane before use to ensure a sterile environment during the culture process.

4. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: In S1, the temperature of the thermostatic shaker was set at 25±1° C., the light intensity was 2000 Lux, and the photoperiod was 12 hours of light / 12 hours of darkness.

5. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: The S3, when cultured in the bioreactor, adopts a combination of batch and continuous culture, with batch culture adopted in the initial stage and switched to continuous culture mode 24 hours after inoculation to achieve rapid start-up and stable maintenance of the growth of Chlorella, and in the continuous culture mode, the flow acceleration rate is controlled at 0.1 times the volume / day to match the discharge rate to maintain a constant cell density.

6. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: The S5, online biomass monitoring sensor is a densitometer, which estimates biomass by measuring the scattering or absorption of light of a specific wavelength by the culture solution. The measurement range of the densitometer is 0-4OD units, the accuracy is ±0.001OD units, and the real-time data update frequency is 1 minute / time.

7. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: The S5, automatic pH controller includes a pH electrode, a control system, an acid-base regulator storage tank and a precision metering pump. The pH value of the culture solution is monitored in real time by the pH sensitive electrode, and a constant pH value is maintained by adjusting the addition of acid-base solution through the acid-base regulator storage tank and the precision metering pump.

8. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: The S5, dissolved oxygen (DO) detector includes an oxygen-sensitive fluorescent material, a light source, a photodetector and a signal processing unit. The optical dissolved oxygen detector uses the absorption characteristics of oxygen molecules to light of a specific wavelength to measure the dissolved oxygen concentration.

9. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: The S5 data analysis software has a data acquisition interface, based on a real-time data processing algorithm, has a chart generation function, and supports historical data query and analysis; the feedback control system has a communication interface with the bioreactor control system, and based on preset culture conditions, including pH and DO levels, through a PID control algorithm, it can automatically adjust the actuators, including regulating valves and frequency converters.

10. The method for heterotrophic cultivation of Chlorella for high protein production according to claim 1, characterized in that: In S7, when using a centrifuge to collect Chlorella cells, the rotation speed is set to 3000 rpm and the duration is 20 minutes.

Images