Cooperative regulation and control method for realizing microalgae efficient carbon sequestration and high-quality biomass co-production
By using a high-filling-rate carrier, concentrated culture medium, and phosphate buffer in a photobioreactor, the contradiction between carbon fixation efficiency and biomass quality in microalgae carbon fixation technology was resolved. This achieved the co-production of high-efficiency carbon fixation and high-quality biomass, improved photosynthetic activity and light utilization efficiency, and ensured the stability of the culture system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-03
AI Technical Summary
Existing microalgae carbon fixation technology faces a contradiction between carbon fixation efficiency and biomass quality. Uneven light and severe self-shading under high-density cultivation lead to a decrease in photosynthetic efficiency, while phosphorus depletion and pH increase cause system collapse, making it difficult to achieve ultra-high carbon fixation rate, ultra-high biomass yield and stable production of high-quality biomass.
A synergistic regulation method was adopted in the photobioreactor using a high-filling-rate carrier, concentrated culture medium, phosphate buffer system and high-concentration carbon dioxide. This included a carrier filling rate of 51-78%, a concentrated culture medium concentration of 3-8 times, 0.01-1.0 mol/L phosphate buffer and 5-10% carbon dioxide gas, to optimize the light-dark ratio and light intensity, and to ensure light utilization efficiency and stability of the intracellular and extracellular environment.
It achieves high carbon fixation rate, ultra-high biomass yield and high-quality biomass production, stable photosynthetic activity, 40% increase in carbon fixation efficiency, improved light utilization efficiency, and stable intracellular signal regulation, avoiding inter-target conflicts of traditional methods.
Smart Images
Figure CN121780327A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial biotechnology, and in particular to a synergistic regulation method for achieving efficient carbon fixation by microalgae and co-production of high-quality biomass. Background Technology
[0002] Utilizing microalgae for carbon dioxide biofixation and converting it into high-value biomass is a crucial pathway to achieving carbon neutrality. *Chlorella pyrenoidosa*, due to its rapid growth and adaptability, is considered a highly promising carbon-fixing algae species. However, existing technologies face a series of bottlenecks in practical applications: There is an irreconcilable contradiction between carbon fixation efficiency and biomass quality. Traditional methods to increase the carbon fixation rate, such as increasing the carbon dioxide concentration to 5-20%, can promote photosynthesis but often conflict with the production of high biomass yields, especially high-quality (e.g., high-protein) biomass. Nitrogen and phosphorus stress strategies to induce lipid or carbohydrate accumulation can increase the content of specific components, but inevitably lead to a decrease in total biomass and a reduction in the carbon fixation rate, severely limiting the overall economic viability of microalgal carbon fixation technology.
[0003] High-density culture presents significant engineering limitations. Whether in suspension or attached culture, when biomass reaches a high level, uneven lighting and severe self-shading lead to photolimited deep cells, causing a sharp decline in photosynthetic efficiency. At the same time, rapid metabolism consumes a large amount of nutrients, especially phosphorus in conventional culture media (such as BG11), which is rapidly depleted. The rapid growth of Chlorella causes a sharp increase in the pH of the culture medium (>11), which disrupts enzyme activity and inorganic carbon balance, causing the system to collapse and making it impossible to maintain a high carbon fixation rate.
[0004] Therefore, current microalgae carbon fixation technology urgently needs a cultivation strategy that can simultaneously achieve ultra-high carbon fixation rate, ultra-high biomass yield, and high-quality biomass composition, while maintaining a stable and controllable process. Summary of the Invention
[0005] To address the problems in the prior art, this invention provides a synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae. This application effectively achieves a cultivation method with high carbon fixation rate, ultra-high biomass yield, and high-quality biomass production by adjusting carrier attachment, culture medium concentration, phosphate buffer system, photobioreactor, and carbon dioxide concentration.
[0006] This invention provides a synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae, employing the following technical solution: A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae includes the following steps: S1. Construct a culture system by filling a photobioreactor with a bioaffinity carrier, wherein the carrier has a filling rate of 51-78% in the photobioreactor; S2. Inoculate Chlorella proteoglycans into the culture system and culture it using concentrated culture medium. The concentration of each inorganic salt in the concentrated culture medium is 3-8 times that of the standard BG11 medium without phosphate. S3. Add phosphate buffer solution with a concentration of 0.01-1.0 mol / L to the culture system; S4. Introduce a mixed gas containing carbon dioxide for incubation.
[0007] In a preferred embodiment, the carrier loading rate is 25-45 g / L.
[0008] In a preferred embodiment, the photobioreactor has a diameter of 110 mm.
[0009] In a preferred embodiment, the volume concentration of carbon dioxide in the mixed gas is 5-10%.
[0010] In a preferred embodiment, the phosphate buffer solution is composed of KH2PO4 and Na2HPO4, with a pH of 6.8-7.5.
[0011] In a preferred embodiment, the concentration of the phosphate buffer is 0.01-0.2 mol / L.
[0012] In a preferred embodiment, the standard BG11 culture medium contains the following components per liter: 1.50 g NaNO3, 0.075 g MgSO4·7H2O, 0.036 g CaCl2·2H2O, 6.00 mg citric acid, 6.00 mg ferric ammonium citrate, 0.01 g Na2EDTA·2H2O, 0.02 g Na2CO3, 2.86 mg H3BO3, 1.81 mg MnCl2·H2O, 0.222 mg ZnSO4·7H2O, 0.079 mg CuSO4·5H2O, 0.39 mg Na2MoO4·2H2O, and 0.049 mg Co(NO3)2·6H2O.
[0013] In a preferred embodiment, the culture conditions in step S4 are: light intensity of 4000-6000 lux, light-dark ratio of (16-20)h:(4-8)h, and culture temperature of 24-26℃.
[0014] In a preferred embodiment, the ventilation rate of the mixed gas is 0.024 vvm.
[0015] By adopting the above technical solution, this application effectively achieves excellent carbon fixation rate, carbon fixation efficiency, and high content of biomass proteins and lipids through the synergistic combination of a 110mm diameter photobioreactor, a high-filling-volume carrier, high-concentration carbon dioxide, concentrated nutrient solution, and phosphate buffer. The synergistic effect stems from precise intervention in the microalgal physiological network, specifically as follows: a high-filling-volume carrier and appropriate carrier loading rate are key driving factors for rapid carbon fixation; the synergistic regulation of its physical space and nutrient availability effectively improves mass transfer, thereby stabilizing photosynthetic activity and prolonging peak carbon fixation efficiency. To improve carbon sequestration rate, the diameter of the photobioreactor can be optimized. By minimizing light attenuation and self-shading, the overall light utilization efficiency was increased by 40%, ensuring that photons could be captured and utilized more effectively throughout the culture system, thereby maintaining high-speed carbon fixation. High-concentration carbon dioxide directly improved the supply of carbon substrates and fundamentally enhanced the mass transfer driving force for rapid carbon fixation, while inhibiting photorespiration. Concentrated nutrient solution provided recombinant "nitrogen skeleton" and other synthetic raw materials, while phosphate buffer stabilized the extracellular pH and regulated intracellular signals (inhibiting phosphorus starvation response and preventing carbon flow mismatch). These four components acted on key nodes of cell metabolism, synergistically pushing the cell state towards an ideal range of high-speed growth, efficient carbon fixation, and balanced synthesis of high-value products.
[0016] Furthermore, the combination of high-concentration carbon dioxide and phosphate buffer solution can effectively promote the regeneration of adenosine triphosphate and the activation of ribulose-1,5-bisphosphate carboxylase / oxygenase, enhance the conversion of photosynthesis and inhibit photorespiration. Moreover, the synergistic effect between the two can not only prevent the severe alkalization of carbon dioxide on its own, but also avoid the problem of excessive diurnal variation caused by pH buffering. This reduces the potential for damage to the electrochemical gradient on the thylakoid membrane due to excessive diurnal temperature variation, thereby enhancing the potential for carbon fixation. Furthermore, the introduction of phosphate buffer can counteract metabolic alkalinity during culture and is essential for ATP and nucleic acid synthesis, which are crucial for cell proliferation and protein synthesis. Phosphate also affects carbon allocation; sufficient phosphate levels prevent the activation of phosphate starvation response pathways, avoiding excessive carbon allocation to starch and lipid synthesis, and instead promoting carbon flow allocation to the synthesis of growth-related proteins and energy storage compounds. In addition, its synergistic effect with high concentrations of carbon dioxide maintains the pH of the culture system within a stable range, ensuring that the dissolved inorganic carbon pool is mainly composed of bioavailable carbon dioxide. This stability is crucial for maintaining the non-equilibrium carbon flow required for high-speed carbon fixation. Carrier attachment is the main driving factor for high-speed carbon fixation, followed by the presence of concentrated nutrient solution, carbon dioxide concentration, and phosphate buffer. All four are indispensable and work synergistically to achieve high-speed carbon fixation.
[0017] In summary, the present invention has the following beneficial effects: This application effectively improves carbon fixation efficiency, biomass yield, protein and lipid content by synergistically combining four elements: using the carrier system as a foundation to ensure energy capture efficiency, sufficient high-concentration carbon dioxide to enhance carbon substrate supply and inhibit photorespiration, concentrated nutrient solution to provide sufficient nitrogen backbone and other synthetic raw materials, and phosphate buffer to stabilize the extracellular environment and regulate intracellular signals (inhibiting phosphorus starvation response, preventing carbon flow mismatch, and enabling more carbon to participate in protein synthesis rather than lipid synthesis). This breaks the long-standing trade-off between objectives in this field. Attached Figure Description
[0018] Figure 1 These are simulation results of the photoreactor optical path in Embodiments 1 and 6 of this application.
[0019] Figure 2 These are carbon dioxide fixation rate graphs for Examples 1 and 6 of this application. Figure 3 This is a graph showing the carbon dioxide fixation rate of Examples 6-10 of this application.
[0020] Figure 4 These are nutrient consumption detection graphs and carbon fixation rate graphs for Example 6, Comparative Example 1, and Comparative Examples 6-8 of this application. Detailed Implementation
[0021] The present invention will be further described in detail below with reference to the accompanying drawings. All reagents, unless otherwise specified, are commercially available conventional reagent products.
[0022] The Chlorella proteoglycans used in this application were purchased from the Institute of Hydrobiology, Chinese Academy of Sciences (Wuhan, China), with species number FACHB-9.
[0023] Phosphate-free standard BG11 medium was used as the basal culture medium (phosphate-free basal medium is to avoid precipitation before use), prepared with pure water, containing the following components per liter: 1.50g NaNO3, 0.075g MgSO4·7H2O, 0.036g CaCl2·2H2O, 6.00mg citric acid, 6.00mg ferric ammonium citrate, 0.01g Na2EDTA·2H2O, 0.02g Na2CO3, 2.86mg H3BO3, 1.81mg MnCl2·H2O, 0.222mg ZnSO4·7H2O, 0.079mg CuSO4·5H2O, 0.39mg Na2MoO4·2H2O, and 0.049 mg Co(NO3)2·6H2O. Example 1
[0024] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae includes the following steps: S1. A culture system was constructed by filling a cylindrical photobioreactor with a diameter of 190 mm with sterilized bio-affinity carriers. The carriers in the photobioreactor had a filling rate of 78%. The carriers were stacked balls made of polyethylene terephthalate fibers, and the carrier loading rate was 30 g / L. S2. Inoculate the expanded Chlorella proteoglycans culture system, then add concentrated culture medium and phosphate buffer for culture, ensuring the pH of the system is maintained at 7.1; the concentration of each inorganic salt in the concentrated culture medium is 5 times the concentration of the standard BG11 medium without phosphate; the concentration of the phosphate buffer is 0.01 mol / L. S3. Set the light-dark ratio of the photobioreactor to 18h:6h (18h of light, 6h of darkness). S4. A simulated power plant flue gas mixture is introduced into the mixed gas, wherein the volume concentration of each gas in the mixed gas is 7% CO2, 4% O2 and 89% N2, the gas flow rate is 0.024 vvm, the constant light intensity is 5000 lux, and the temperature is 25±1℃. Example 2
[0025] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae is disclosed. The difference between this method and Example 1 is that the carrier filling rate in the photobioreactor is 67%, while all other aspects are the same as in Example 1. Example 3
[0026] A synergistic regulation method for achieving efficient carbon fixation by microalgae and co-production of high-quality biomass is disclosed. The difference between this method and Example 1 is that the carrier filling rate in the photobioreactor is 62%, while all other aspects are the same as in Example 1. Example 4
[0027] A synergistic regulation method for achieving efficient carbon fixation by microalgae and co-production of high-quality biomass is disclosed. The difference between this method and Example 1 is that the carrier filling rate in the photobioreactor is 54%, while all other aspects are the same as in Example 1. Example 5
[0028] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae is disclosed. The difference between this method and Example 1 is that the carrier filling rate in the photobioreactor is 51%, while all other aspects are the same as in Example 1. Example 6
[0029] A synergistic regulation method for achieving efficient carbon fixation by microalgae and co-production of high-quality biomass is disclosed. The difference between this method and Example 1 is that the diameter of the cylindrical photobioreactor is 110 mm and the carrier filling rate in the photobioreactor is 78%. All other aspects are the same as in Example 1. Example 7
[0030] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae is disclosed. The difference between this method and Example 6 is that the carrier loading rate is 25 g / L, while all other aspects are the same as in Example 1. Example 8
[0031] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae is disclosed. The difference between this method and Example 6 is that the carrier loading rate is 35 g / L, while all other aspects are the same as in Example 1. Example 9
[0032] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae is disclosed. The difference between this method and Example 6 is that the carrier loading rate is 40 g / L, while all other aspects are the same as in Example 1. Example 10
[0033] A synergistic regulation method for achieving efficient carbon fixation and high-quality biomass co-production of microalgae is disclosed. The difference between this method and Example 6 is that the carrier loading rate is 45 g / L, while all other aspects are the same as in Example 1. Comparative Example 1
[0034] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is disclosed. The difference between this method and Example 1 is that a basic culture medium is added in step S2, while all other steps are the same as in Example 1. Comparative Example 2
[0035] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is disclosed. The difference between this method and Example 2 is that a basic culture medium is added in step S2, while all other steps are the same as in Example 2. Comparative Example 3
[0036] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is disclosed. The difference between this method and Example 3 is that a basic culture medium is added in step S2, while all other steps are the same as in Example 3. Comparative Example 4
[0037] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is disclosed. The difference between this method and Example 4 is that a basic culture medium is added in step S2, while all other steps are the same as in Example 4. Comparative Example 5
[0038] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is different from Example 5 in that a basic culture medium is added in step S2, while all other steps are the same as in Example 5. Comparative Example 6
[0039] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is disclosed. The difference between this method and Example 6 is that phosphate buffer is not added in step S2, and the pH of the system is adjusted to 7.1 before use. All other aspects are the same as in Example 6. Comparative Example 7
[0040] A method for synergistic regulation of microalgal carbon fixation and biomass co-production is disclosed. The difference between this method and Example 6 is that air is introduced for cultivation in step S4, while all other steps are the same as in Example 6. Comparative Example 8
[0041] A method for synergistic regulation of microalgal carbon fixation and biomass co-production, without carrier, using suspension culture, and otherwise identical to that in Example 6. control group
[0042] Suspension culture was carried out in a cylindrical photobioreactor with a diameter of 190 mm without adding a carrier and using a basic culture medium. No phosphate buffer was added. Before use, the pH of the system was adjusted to 7.1 and air was introduced for culture. Analysis and testing
[0043] In the above-mentioned scheme of this application, the culture period of Chlorella proteoglycans is 3 days. During the culture period, algal solution samples are taken and analyzed regularly. The specific test results are shown in the table below.
[0044] 1. Detection of total stem biomass of Chlorella proteoglycans The suspended algal solution was collected by centrifugation using a sampler, washed twice with deionized water, and dried to constant weight at -40°C. The wet biomass of microalgae on the carrier was detached by ultrasonic vibration. The detached biomass was filtered (using a 0.45 μm filter membrane), washed, dried to constant weight at -40°C, and the total dry biomass yield of both parts was recorded.
[0045] 2. Carbon fixation rate and efficiency: The carbon fixation rate represents the absolute mass of carbon dioxide converted per unit reactor volume per day. It is a key indicator for evaluating system productivity and is calculated using Formula 1: (1) in, It is the carbon fixation rate; The algal carbon content (%) was measured using an elemental analyzer (Elementar Vario EL Cube, Germany). It is the growth rate of algae (g / L / d); It is the molar mass of CO2 (g / mol); It is the molar mass of C (g / mol).
[0046] To further evaluate the carbon utilization efficiency of the system, the carbon dioxide fixation efficiency is defined as the percentage of carbon dioxide supplied that is absorbed by the biomass, according to Formula 2: (2) in, The carbon dioxide fixation efficiency is given by Y, total dry biomass (g), air flow rate (L / h), and CO is the inlet carbon dioxide concentration (volume ratio, 7% in this study). Carbon dioxide gas density, t is aeration time (h).
[0047] 3. Optical Path Simulation Analysis: A photoreactor model was built using TracePro software to simulate the light intensity and irradiated surface of the constructed photoreactor. The light source properties were set to radiative emission type, with emitted rays conforming to a Lambertian distribution. The external LED light source was configured with an intensity of 5000 lux, a total of 100,000 rays, and a wavelength of 520 nm. The average irradiance was derived from the simulation results of TracePro software. The light coverage efficiency was calculated using Formula 3: (3) Where LCE is the light coverage efficiency, S e It is an area with a light intensity greater than 2500 lux, S total It is the total area under illumination.
[0048] Light uniformity is calculated using formula 4: (4) Where σ is the standard deviation, This is the average irradiance in the simulation results. The closer LU is to 1, the better the uniformity.
[0049] Relative light utilization efficiency is calculated using formula 5: (5) Where E2 is the energy (J) fixed in the biomass before the light distribution optimization, and E1 is the energy (J) fixed in the biomass after the light distribution optimization, and it is assumed that the energy of the actual incident light is constant.
[0050] 4. Nutritional consumption Nitrate concentration was determined by the phenol disulfonic acid method (UV-Vis spectrophotometer, detection at 220 nm, calibration at 275 nm).
[0051] Total phosphate concentration was determined by the molybdenum antimony method (UV-Vis spectrophotometer, 700 nm detection). Data were normalized to the initial nutrient level and expressed as removal efficiency (%). The results are shown below. Figure 4 As shown.
[0052] 5. Determination of protein, polysaccharide and lipid content Protein content was determined using the Folin-phenol reagent method, polysaccharide content was determined using the phenol-sulfuric acid method, and polysaccharide content was determined by extraction with chloroform-methanol (volume ratio 2:1) and gravimetric analysis.
[0053] Table 1. Results of total dry biomass detection of Chlorella proteoglycans, unit: g / L project 3h 6h 9h 12h 24h 48h 72h Example 1 0.60 1.30 1.97 2.70 4.50 6.17 8.22 Example 2 0.46 0.91 1.29 2.00 3.17 6.36 8.95 Example 3 0.36 0.82 1.21 1.70 2.85 6.22 8.89 Example 4 0.30 0.78 1.15 1.55 2.59 4.72 8.40 Example 5 0.34 0.69 1.08 1.56 2.74 5.51 8.81 Example 6 0.57 1.51 3.12 4.42 6.31 8.43 10.25 Example 7 0.61 1.62 2.22 2.72 4.78 6.23 7.17 Example 8 0.96 2.38 2.80 3.61 4.14 4.90 5.44 Example 9 0.70 1.88 2.86 3.77 3.89 4.21 4.90 Example 10 0.32 1.43 2.32 2.97 3.37 3.95 5.39 Comparative Example 1 0.21 0.31 0.58 0.92 1.75 / / Comparative Example 2 0.18 0.27 0.55 0.85 1.55 / / Comparative Example 3 0.15 0.26 0.52 0.80 1.54 / / Comparative Example 4 0.15 0.20 0.42 0.68 1.31 / / Comparative Example 5 0.14 0.24 0.50 0.80 1.45 / / Comparative Example 6 0.40 1.29 2.31 2.59 4.03 5.15 4.45 Comparative Example 7 0.35 0.97 1.92 2.68 2.97 3.67 3.61 Comparative Example 8 0.12 0.10 0.18 0.26 0.61 1.16 1.71 control group 0.06 0.06 0.06 0.06 0.06 / / As can be seen from the total dry biomass test results in Table 1: Compared with Comparative Examples 1-5, under the same conditions, Examples 1-5 used concentrated culture medium, while Comparative Examples 1-5 used basic nutrient solution. The biomass obtained in Examples 1-5 was significantly higher than that in Comparative Examples 1-5 at the corresponding time and under the corresponding carrier filling conditions. This shows that under the same carrier filling rate, the addition of concentrated nutrient solution can effectively achieve high biomass.
[0054] As can be seen from Examples 1-5, under the same nutrient solution conditions, the total dry biomass showed an upward trend within 24 hours as the carrier filling density increased. However, at 72 hours, the total dry biomass showed a trend of first decreasing, then increasing, and then decreasing again as the carrier filling density increased. This shows that the requirement for high biomass can be met when the carrier filling density is between 51% and 78%.
[0055] Compared to Example 1, under the same carrier packing density and nutrient solution conditions, Example 6, by reducing the diameter of the photobioreactor, produced a significantly higher biomass of *Chlorella proteoglycans* than Example 1. This demonstrates that the photobioreactor in Example 6, compared to the one in Example 1, exhibited a 53% increase in average irradiance, a 53% increase in light uniformity, and a 119% increase in coverage. Therefore, reducing the diameter of the photobioreactor created a more favorable photon environment, effectively improving light uniformity and coverage. Specific test results are as follows: Figure 2 As shown, the final dry biomass yield after 72 hours of cultivation was significantly higher than the total dry biomass yield in Example 1.
[0056] Compared with Example 6, the biomass produced by Chlorella proteoglycans in Examples 7-10 was lower than that in Example 6 as the carrier loading rate increased. This is because when the loading rate is too low, the attachment area of Chlorella proteoglycans is insufficient, while too high a loading rate (>35 g / L) may affect the flow field and light transmission efficiency in the reactor, resulting in a significant reduction in the final dry biomass due to the excessively high carrier loading rate. Therefore, the carrier loading rate (30 g / L) in Example 6 is the optimal carrier loading rate, balancing the relationship between the maximum attachment area and maintaining good hydrodynamics and light penetration.
[0057] Compared with Example 6, when phosphate buffer was lacking, air was introduced without carbon control, or suspension culture was performed without a carrier, the total dry biomass of Chlorella proteoglycans produced in Comparative Examples 6-8 was significantly lower than that in Example 6. This shows that the effective combination of high concentration of carbon dioxide, concentrated culture medium and phosphate buffer, 110 mm photobioreactor, carrier loading and carrier filling rate in this application maintains better stability of the culture system, thereby increasing the total dry biomass.
[0058] Table 2. Carbon fixation efficiency of Chlorella proteoglycans, in % project 24h 48h 72h Example 1 35.53 24.35 21.61 Example 2 24.98 25.08 23.54 Example 3 22.48 24.56 23.37 Example 4 20.36 18.62 22.08 Example 5 21.65 21.73 23.15 Example 6 49.77 33.26 26.94 Example 7 37.71 24.78 18.87 Example 8 32.62 19.34 14.30 Example 9 30.67 16.59 12.88 Example 10 26.55 15.58 14.17 Comparative Example 1 13.80 4.78 2.66 Comparative Example 2 12.24 8.93 7.96 Comparative Example 3 12.11 9.34 8.58 Comparative Example 4 10.34 8.92 9.67 Comparative Example 5 11.44 10.22 10.83 Comparative Example 6 31.80 20.31 11.69 Comparative Example 7 23.40 14.47 9.51 Comparative Example 8 4.80 4.59 4.50 control group 3.57 5.72 5.31 The carbon dioxide fixation rate diagrams for Examples 1, 6-10, Comparative Examples 1, and 6-8 of this application are shown below. Figure 2-4 As shown, where Figure 2 In this context, PS-Base represents Example 1, and PS-Adv represents Example 6.
[0059] The protein, total sugar, and lipid contents of *Chlorella vulgaris* obtained from the control group, Example 6, Comparative Example 1, Comparative Example 6, Comparative Example 7, and Comparative Example 8 were recorded, and the detection results are shown in Table 3.
[0060] Table 3. Results of Detection of Valuable Components in Chlorella proteoglycans (Unit: mg / g)
[0061] Combining the test data in Tables 1, 2, and 3, it can be seen that: With the optimization of concentrated culture medium and phosphate buffer, light path of photobioreactor, high carbon dioxide concentration and suitable carrier attachment, the Chlorella proteoglycans obtained in Example 6 of this application not only have significantly higher dry biomass, protein content and polysaccharide content than other substances, but also have higher lipid content. It can be seen that the optimized system in Example 6 can show a superior and more balanced carbon distribution, enabling carbon to be distributed to valuable macromolecules.
[0062] Compared with Example 6, when phosphate buffer was missing, the protein level in Comparative Example 6 was significantly lower than that in Example 6. This indicates that phosphate buffer is indispensable for maintaining pH stability and as a core component of ATP and nucleic acids, which are necessary for cell proliferation and protein synthesis.
[0063] Compared to Example 6, Comparative Example 8, lacking a carrier, exhibited a higher lipid content and a significantly lower protein content than Example 6 of this application. This is because, with a fixed carbon supply, the carrier-free group required stress resistance, leading to increased carbon involvement in lipid synthesis. In contrast, Example 6, protected by a carrier, did not require the production of as much lipid for stress resistance, allowing for greater carbon participation in protein synthesis. Therefore, this application demonstrates that by optimizing carrier attachment, light utilization, and selecting a high carbon dioxide concentration and high nutrient solution, the Chlorella proteoglycans obtained in Example 6 exhibit superior performance.
[0064] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae, characterized in that, Includes the following steps: S1. Construct a culture system by filling a photobioreactor with a bioaffinity carrier, wherein the carrier has a filling rate of 51-78% in the photobioreactor; S2. Inoculate Chlorella proteoglycans into the culture system and culture it using concentrated culture medium. The concentration of each inorganic salt in the concentrated culture medium is 3-8 times that of the standard BG11 medium without phosphate. S3. Add phosphate buffer solution with a concentration of 0.01-1.0 mol / L to the culture system; S4. Introduce a mixed gas containing carbon dioxide for incubation.
2. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The carrier loading rate is 25-45 g / L.
3. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The photobioreactor has a diameter of 110 mm.
4. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The volume concentration of carbon dioxide in the mixed gas is 5-10%.
5. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The phosphate buffer solution is composed of KH2PO4 and Na2HPO4, with a pH of 6.8-7.
5.
6. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The concentration of the phosphate buffer solution is 0.01-0.2 mol / L.
7. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The standard BG11 medium contains the following components per liter: 1.50g NaNO3, 0.075g MgSO4·7H2O, 0.036g CaCl2·2H2O, 6.00mg citric acid, 6.00mg ferric ammonium citrate, 0.01g Na2EDTA·2H2O, 0.02g Na2CO3, 2.86mg H3BO3, 1.81mg MnCl2·H2O, 0.222mg ZnSO4·7H2O, 0.079mg CuSO4·5H2O, 0.39mg Na2MoO4·2H2O, and 0.049mg Co(NO3)2·6H2O.
8. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The cultivation conditions in step S4 are: light intensity 4000-6000 lux, light-dark ratio of (16-20)h:(4-8)h, and cultivation temperature of 24-26℃.
9. The method for synergistic regulation of efficient carbon fixation and high-quality biomass co-production by microalgae according to claim 1, characterized in that: The ventilation rate of the mixed gas is 0.024 vvm.