Chlorella and application thereof in carbon sequestration, emission reduction and biological fertilizer co-production

Abstract

The invention discloses chlorella and application thereof in carbon sequestration and emission reduction and co-production of a biological fertilizer, and a process for coupling carbon sequestration and emission reduction of microalgae and utilization of a microalgae biological fertilizer in flue gas of a power plant comprises the following steps: 1) culturing an algal strain in the flue gas of the power plant, and 2) harvesting the algal strain cultured in the step 1) and using the algal strain to prepare the microalgae biological fertilizer. Through experiments, aiming at the defects of the traditional flue gas treatment technology of the coal-fired power plant, the invention adopts a microalgae carbon sequestration technology which is environment-friendly, economical and efficient and conforms to the natural circulation characteristics, and is coupled with a microalgae biological fertilizer, so that the flue gas treatment is realized, the flue gas resource utilization is realized, the whole ecological chain is prolonged, and the environmental protection is realized. And the full-life-cycle carbon sequestration emission reduction amount is effectively increased.

Description

Technical Field

[0001] The present invention relates to the field of microbial technology, in particular to a Chlorella kjeldahlii algae with high tolerance to power plant flue gas and application thereof in carbon sequestration, emission reduction and parallel production of biofertilizer. Background Art

[0002] Coal-fired power generation emissions are a major source of carbon emissions, with exhaust gas containing large amounts of CO2 and trace pollutants, including SO2, NOx, and smoke.

[0003] Traditional flue gas CO2 treatment technologies primarily include chemical and physical methods such as separation, absorption, recovery, and ammonia synthesis. However, traditional coal-fired power plant flue gas emission reduction technologies are generally plagued by complex process equipment, high energy consumption, and high treatment costs. As a result, no mature decarbonization technology exists to address the CO2 emissions problem in coal-fired power plants.

[0004] Microalgae are a type of photosynthetic autotrophic eukaryotic or prokaryotic microorganisms that convert CO2, water, and light energy into oils, carbohydrates, and proteins through photosynthesis to achieve their own growth. They are characterized by rapid growth and high photosynthetic carbon fixation efficiency. For example, their carbon fixation efficiency is 5-10 times that of ordinary terrestrial plants. Compared with traditional chemical and physical treatment technologies, microalgae flue gas carbon fixation and emission reduction technology is a new technology that couples biology and chemistry. It has the advantages of being environmentally friendly, economical, efficient, and consistent with the characteristics of natural cycles. However, microalgae carbon fixation technology has shortcomings such as a short life cycle and difficult subsequent processing of microalgae, which limits the large-scale application of microalgae treatment technology. Summary of the Invention

[0005] To address the shortcomings of the aforementioned prior art, the present invention isolated and screened a strain of Chlorella kessleri. Pot experiments and cultivation in actual power plant flue gas confirmed that this microalgae exhibits rapid growth, high stress tolerance, and high fertilizer efficiency, all tailored to the specific characteristics of power plant flue gas emissions. This microalgae cultivation process achieves flue gas carbon sequestration and emission reduction, as well as flue gas resource utilization. This coupling of microalgae carbon sequestration and emission reduction in power plant flue gas with microalgae biofertilizer utilization improves the technology's economic efficiency while extending the entire ecosystem, effectively increasing carbon sequestration and emission reduction throughout its lifecycle.

[0006] According to one aspect of the present invention, a Parachlorella kessleri algae strain Chlorella sp. HY1 is provided, which is deposited in the China Center for Type Culture Collection with a deposit number of CCTCC NO: M 2025689.

[0007] According to another aspect of the present invention, there is provided a use of the Chlorella vulgaris of the present invention in carbon sequestration and emission reduction in power plant flue gas and in parallel production of biofertilizer.

[0008] According to an embodiment of the present invention, the Chlorella vulgaris is cultured in flue gas from a power plant.

[0009] According to another aspect of the present invention, a method for coupling microalgae carbon sequestration and emission reduction in power plant flue gas with microalgae biofertilizer utilization is provided, comprising:

[0010] 1) Cultivating the algae strain of the present invention in power plant flue gas; and

[0011] 2) Harvesting the algae cultured in step 1) and using it to prepare microalgae biofertilizer.

[0012] According to an embodiment of the present invention, in step 1), the carbon fixation efficiency of the algae strain is above 0.5 g / L / d.

[0013] According to an embodiment of the present invention, step 2 includes compounding the harvested algae strains with other fertilizers to form microalgae biofertilizer, and the other fertilizers include inorganic fertilizers, organic fertilizers or bacterial biofertilizers.

[0014] According to an embodiment of the present invention, in step 2, the microalgae biofertilizer comprises an active microalgae fertilizer liquid product.

[0015] Compared to existing technologies, this invention provides microalgae with improved flue gas tolerance, high carbon sequestration efficiency, and excellent fertilizer effectiveness. Specifically, the invention achieves flue gas carbon sequestration and emission reduction during the microalgae cultivation process. By coupling microalgae carbon sequestration and emission reduction in power plant flue gas with the use of microalgae as biofertilizer, this technology achieves flue gas resource utilization. This improves the economic efficiency of the technology while extending the entire ecological chain, reducing later-stage microalgae waste emissions, and effectively increasing carbon sequestration and emission reduction throughout the entire life cycle. This process offers advantages such as environmental friendliness, cost-effectiveness, simplicity, efficiency, and compliance with natural cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The following is a photograph of the morphological characteristics of the Parachlorella kessleri algae strain Chlorella sp.HY1 under an optical microscope according to the present invention;

[0017] Figure 2 is a phylogenetic tree of the 18S rDNA sequence of the Parachlorella kessleri algae strain Chlorella sp.HY1 according to the present invention;

[0018] Figure 3 A process system diagram of coupling microalgae carbon sequestration and emission reduction in power plant flue gas with microalgae biofertilizer utilization according to an embodiment of the present invention;

[0019] Figure 4 Schematic diagram of a microalgae cultivation system according to an embodiment of the present invention;

[0020] Figure 5 These are photos of the whole body and roots of lettuces treated with different methods when verifying the pot fertilizer effect using an algae solution of Chlorella vulgaris cultured with actual flue gas according to an embodiment of the present invention;

[0021] Figure 6 Graph showing the fresh weight experimental results of lettuce treated with different methods according to an embodiment of the present invention;

[0022] Figure 7 is a diagram showing the cell wall breaking effect of Chlorella according to an embodiment of the present invention, and

[0023] Figure 8 This is a graph showing the fresh weight test results of lettuces with different treatments according to another embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in detail through specific embodiments in conjunction with the accompanying drawings. The illustrated contents are used to fully illustrate the contents of the present invention but are not used to limit the present invention.

[0025] The experimental methods in the examples are conventional methods unless otherwise specified, and the chemical and biological reagents used are conventional reagents in the art and can be purchased unless otherwise specified.

[0026] Samples were collected from the soil in the wild to enrich the soil microalgae samples. In a clean bench, 10 g of the collected soil was first weighed and introduced into a conical flask containing 90 mL of sterilized BG11 culture medium. The flask was sealed with gauze and sealing film, and then the conical flask was placed on an oscillator (150 rpm, 30 min) to obtain a 10-fold dilution (10 -1 ) of soil suspension; pipette 10 -1 10 mL of the soil suspension was added to a conical flask containing 90 mL of sterilized BG11 medium to obtain a 100-fold dilution (10 -2 ) soil suspension, repeat this process to obtain 10 -3The soil suspension. The conical flask is then placed in a light incubator (25±1°C, 3000Lux continuous light) for enrichment culture. The conical flask is shaken regularly and examined under a microscope. When the algal cell density reaches 5000cells / mL, the enrichment culture is completed. The algal strain purification process is then carried out. 5g of agar powder is weighed and poured into a conical flask containing 250mL of BG11 culture medium. After shaking well, the bottle mouth is sealed with a sealing film. The cone is placed in a high-pressure sterilizer for sterilization (121°C, 30min). After cooling to 50°C, the agar culture medium is poured into a sterile culture dish in a clean bench. After cooling, a 2% agar solid culture medium is obtained. Use a sterile inoculating loop to dip the algae solution after enrichment culture, streak on the agar solid culture medium, then fully seal the culture dish with a sealing film and place it in a light incubator (25±1°C, 3000Lux continuous light) for continuous culture. After colonies grow on the solid culture medium, pick a single colony into a sterile centrifuge tube containing 5 mL of BG11 culture medium in a clean bench and seal it. Place the centrifuge tube in a light incubator and culture it statically for about 10 days. Examine the algae liquid under an optical microscope and transfer the algae liquid free of bacteria and algae to a sterile conical flask containing 100 mL of BG11 culture medium for expansion culture to obtain a pure algae strain.

[0027] The algae liquid was observed under an optical microscope for morphological observation, and it was found that the algae were oval, about 5-7 μm in size, and had no flagella (see Appendix). Figure 1 ), and named the algae species Chlorella sp.HY1.

[0028] The algae species Chlorella sp.HY1 was commissioned to Sangon Biotech (Shanghai) Co., Ltd. for 18S rDNA sequencing, and the 18S rDNA sequence was subjected to BLAST comparison analysis in the NCBI database. The comparison results showed that the sequence coverage of this algae species and the kessler-like chlorella (Parachlorella kessleri) was 100%, and the sequence similarity was 99.65%. The homologous sequences with the top comparison results in the NCBI database were selected, and homologous evolutionary comparison was performed using ClustalX software to obtain a multiple sequence matching matrix. Then, the phylogenetic tree of the 18S rDNA sequence was constructed using Mega software, the neighbor algorithm, and the bootstraps value of 1000 (see Appendix). Figure 2 ), and the analysis results showed that the algae species was Parachlorella kessleri.

[0029] Therefore, the present invention provides a Chlorella sp. HY1, which was classified and named Chlorella sp. HY1 and deposited with the China Center for Type Culture Collection (CCTCC) on April 2, 2025, at 299 Bayi Road, Wuchang District, Wuhan City, Hubei Province. The deposit date is April 2, 2025, and the deposit number is CCTCC NO: M 2025689.

[0030] After obtaining and identifying the Chlorella vulgaris strain, further experiments were carried out using the Chlorella vulgaris strain.

[0031] Example 1: Experiment on the tolerance of algae strains in simulated flue gas

[0032] Figure 4 This is a diagram of a laboratory simulated flue gas culture system for Chlorella vulgaris strains according to an embodiment of the present invention. As shown in the figure, the system is used to simulate the composition of power plant exhaust gas to cultivate microalgae strains. The components of flue gas emitted by general power plants include CO2, SO2, and NOx, which usually meet the characteristics of ultra-low emission flue gas. However, in actual production, the components in the flue gas will change due to factors such as production processes, especially SO2 and NOx. The concentrations of these substances will affect the growth and development of Chlorella, thereby affecting the carbon fixation effect of Chlorella. In this experiment, other conditions except the influence of flue gas ventilation were fixed, such as temperature, light, and CO2 concentration. After single-factor screening of flue gas ventilation, the growth performance of different algae strains (including control algae strains) under different simulated flue gas concentrations was examined; the experimental conditions are as follows:

[0033] Algae strain: Chlorella keslerae strain (the present invention); control group algae strain: Chlorella ellipsoidea, Scenedesmus;

[0034] Simulated flue gas: flue gas (SO2:NOx:N2=0.49%:0.98%:98.53%), high-purity CO2, high-purity air;

[0035] Light and temperature: Light intensity is about 100 μmol / m 2 / s, cultured in a water bath with controlled temperature (28 ± 0.5 °C);

[0036] Microalgae culture system (see Appendix Figure 4): The gases passed through are a mixture of flue gas (an acidic mixture of NOx and SO2 with a certain concentration), high-purity air and a high-purity carbon dioxide cylinder. The actual concentrations of flue gas, air and CO2 are controlled by adjusting the mass flow meter. An air filter is added to the inlet of the 400ml glass tube to filter out bacteria in the gas passed through. The mass flow meter is adjusted to control the gas flow rate and the gas is introduced into the 400ml glass tube through a glass tube with a pore size of about 2mm. The exhaust gas is collected and discharged into the atmosphere. The 400ml glass tube is placed in a constant temperature water bath made of organic glass with good light transmittance. The temperature of the constant temperature water bath is controlled by a low-temperature constant temperature circulator. The light source used in the experiment is cold light LEDs. The light intensity can be fine-tuned by adjusting the distance between the reactor and the light source. This culture system can ensure that the light intensity, flue gas concentration, CO2 concentration, ventilation rate and temperature are all within a certain controllable range.

[0037] Experimental methods:

[0038] The activated algae were inoculated into a 400ml glass tube containing 300ml of BG11 liquid culture medium. The 400ml glass tube was placed in a water bath with circulation. The water bath temperature was controlled at 28±0.5℃, the CO2 concentration was about 10%, and the microporous membrane filter was used for sterilization. The simulated flue gas ventilation rate was 0.2L / min, and the concentration of about 100μmol / m 2 The cells were cultured under continuous illumination in front of a white LED lamp with a light intensity of / s. The culture and screening period was set at 4 days, and the relevant growth indices were used for comparison.

[0039] First round: Chlorella kesleroides; Chlorella ellipsoides; Scenedesmus

[0040] (1) Initial inoculum size: OD680 = 0.4;

[0041] (2) Flue gas: SO 2( 17.5 mg / m 3 )、NOx(16.69mg / m 3 ); an activation tolerance test was conducted under CO2: 10.0% to examine the growth of the algae strain;

[0042] (3) Algae culture: After 4 days of culture, it was found that:

[0043] (a) Under the experimental conditions, all three algae strains grew normally and no death was found;

[0044] (b) Dry weight data showed that all three algae strains reached above 2.3 g / L, with the dry weight of the Chlorella keslerae strain reaching 2.67 g / L.

[0045] (c) The three algae strains grew well and the differences were relatively small, so the next round of cultivation with increased flue gas concentration was carried out.

[0046] Second round: Chlorella kesleroides; Chlorella ellipsoides; Scenedesmus

[0047] (1) Initial inoculum size: OD680 = 0.4;

[0048] (2) Flue gas: SO2: (35mg / m 3 )、NOx(33.39mg / m 3 ); an activation tolerance test was conducted under CO2: 10.0% to examine the growth of the algae strain;

[0049] (3) Algae culture: After 4 days of culture, it was found that:

[0050] (a) Scenedesmus could not adapt to the smoke concentration and died on the second day. The pH of the algae solution was around 3.1, which was not suitable for algae growth. The algae appeared white.

[0051] (b) Dry weight data: The dry weight of surviving algae strains was above 2.2 g / L;

[0052] (c) Using the two surviving algae strains, conduct a third round of smoke tests, increase the smoke concentration, and proceed to the next round of algae strain tests.

[0053] Round 3: Chlorella vulgaris strains; Chlorella ellipsoidea;

[0054] (1) Initial inoculum size: OD680 = 0.4

[0055] (2) Flue gas: SO2 (78.9 mg / m 3 , about 30ppm), NOx (75.88mg / m3, about 60ppm); CO2: about 11.5% conditions to carry out activation tolerance test and examine the growth status of algae strains.

[0056] (3) Algae culture: After 4 days of culture, it was found that:

[0057] (a) Dry weight data: The Chlorella vulgaris strain grew normally, and its dry weight reached 2.0 g / L;

[0058] (2) Chlorella ellipsoidea died on the first day, and the pH of the algae solution was about 2.8, and the algae solution basically turned milky white;

[0059] (3) Microscopic examination revealed that the Chlorella vulgaris strains were active and had no agglomeration.

[0060] The experimental results are shown in the following table:

[0061]

[0062] As shown above, after three rounds of algae strain tolerance tests with different flue gas concentrations, the flue gas concentration was gradually increased from low concentration (SO 2 From the initial concentration of 17.5 mg / m 3 Increased to about 78.9 mg / m 3 ; NO X From the initial concentration of about 16.7 mg / m 3 Increased to about 75.88 mg / m 3 , CO2 increased from 10% to about 11.5%), and through a comparison of algae performance indicators through a short-cycle cultivation of 4 days, it can be found that the Chlorella vulgaris strain of the present invention has good tolerance in a large range of flue gas concentrations, grows well, and its dry weight is basically above 2.0 g / L. Microscopic examination shows that no agglomeration occurs.

[0063] Example 2: Cultivation of Chlorella vulgaris in Simulated Smoke

[0064] In the laboratory, gas cylinders are used to simulate the flue gas components of power plants: SO2 (70mg / m 3 ), NO x (67mg / m 3 ) and 10% CO2. The activated Chlorella vulgaris was inoculated into a 400ml glass tube containing 300ml of BG11 medium at a concentration of 0.1g / L. The 400ml glass tube was placed in a circulating water bath, the water bath temperature was controlled at 28±0.5°C, the simulated smoke ventilation rate was 0.2L / min, and the concentration was approximately 100μmol / m 2 / s white LED tube for continuous illumination for 8 days. After the experiment, the microalgae biomass was measured, and the maximum dry weight reached was 4.1g / L, and the average carbon fixation rate was 0.943g / L / d.

[0065] Example 3: Cultivation of Chlorella kessleri Using Power Plant Flue Gas

[0066] The actual flue gas emitted by coal-fired power plants (ultra-low emission standards: about 10.0% CO2, 35.2mg / m 3 SO2, 49.7 mg / m 3 The carbon fixation and growth performance of microalgae were evaluated by measuring the NOx removal rate. The activated Chlorella vulgaris strain was inoculated into a 10L column reactor filled with 7LBG11 culture medium, which was placed in an on-site container. The inoculation concentration was 0.1g / L. The air-conditioned room temperature was 25°C, the actual flue gas ventilation rate was 5L / min, and the cells were cultured under continuous illumination in front of a white LED lamp of approximately 15,000Lux for 8 days. After the experiment, the microalgae biomass was measured, reaching a maximum dry weight of 3.5g / L and an average carbon fixation rate of 0.805 / L / d.

[0067] Example 4: Cultivation of Chlorella kesslerae using power plant flue gas

[0068] The actual flue gas emitted by coal-fired power plants (ultra-low emission standards: ultra-low emission standards: about 10.0% CO2, 35.2mg / m 3 SO2, 49.7 mg / m 3 The carbon fixation and growth performance of microalgae were evaluated by measuring the NOx. The activated Chlorella vulgaris strain was inoculated into a column reactor (10 L) filled with 7 LBG11 culture medium, and the reactor was placed in an on-site container. The inoculation concentration was 0.1 g / L. The indoor temperature varied from 15-35 ° C, the actual flue gas ventilation rate was 6 L / min, and the daytime sunlight varied from about 1500-25000 Lux. The culture lasted for 8 days. After the experiment, the microalgae biomass was measured, and the maximum dry weight reached was 2.4 g / L, and the average carbon fixation rate was 0.552 g / L / d.

[0069] Example 5: Experiment on the biofertilizer of Chlorella vulgaris liquid

[0070] Figure 3 The process flow for coupling power plant flue gas microalgae carbon sequestration and emission reduction with microalgae biofertilizer utilization according to an embodiment of the present invention is shown. In this example, a flowerpot fertilizer efficacy experiment was conducted using the actual flue gas culture of Chlorella vulgaris in Example 4. Using lettuce as the model plant, four treatments were set up: Treatment 1 (control, CK), Treatment 2 (C1, 15 mL of algae solution), Treatment 3 (C2, 30 mL of algae solution), and Treatment 4 (C3, 50 mL of algae solution), with three replicates per treatment. Each pot contained 2 L of nutrient soil (organic fertilizer and coconut bran, 1:1 (v / v)). Twelve lettuce plants of identical size and growth status were selected, with one seedling planted in each pot. Fertilization was performed on the day of transplanting the lettuces. Each pot was first irrigated with 100 mL of garden nutrient solution (GNS), followed by the addition of 15, 30, and 50 mL of algae solution to Treatments 2, 3, and 4, respectively. On the fourth day, 50 mL of water was added to all treatment groups. On the 7th and 11th days, each treatment group was irrigated with 100 mL of GNS. After 20 days of cultivation, the lettuce leaves on the upper soil layer were harvested. Figure 5 The whole picture and root picture of different lettuce treatments at harvest time are shown below. The fresh weight of each treatment is as follows: Figure 6 Compared to the control group without algae solution, the fresh weight of the treatment groups with 15 mL, 30 mL, and 50 mL of algae solution increased by 18.0%, 23.0%, and 32.8%, respectively. These results demonstrate that the Chlorella vulgaris of the present invention has significant fertilizer efficacy.

[0071] Example 6: Experiment on biofertilizer of Chlorella vulgaris lysate

[0072] The chlorella algae liquid harvested in Example 4 was subjected to cell wall breaking treatment using a high-pressure homogenizer. The pressure was adjusted to 1000-1400 bar and the mixture was circulated 3-4 times. The cell wall breaking temperature was controlled at 4°C by a circulating cold water system. The cell wall breaking rate of the chlorella algae after cell wall breaking was above 90%. The cell wall breaking effect was shown in the attached figure. Figure 7 .

[0073] The microalgae lysate obtained above was used as the experimental fertilizer. Using lettuce as the model plant, four treatments were set up: Treatment 1 (control, CK), Treatment 2 (C1, 15 mL of microalgae lysate), Treatment 3 (C2, 30 mL of microalgae lysate), and Treatment 4 (C3, 50 mL of microalgae lysate), with three replicates per treatment. Each pot contained 2 L of nutrient soil (organic fertilizer and coconut bran, 1:1 (v / v)). Twelve lettuce plants of similar size and growth status were selected, and one seedling was planted in each pot. Fertilization treatments were performed on the day of transplanting the lettuce. Each pot was first irrigated with 100 mL of garden nutrient solution (GNS), followed by the addition of 15, 30, and 50 mL of microalgae lysate to Treatments 2, 3, and 4, respectively. On the fourth day, 50 mL of water was added to all treatments. On the seventh and eleventh days, each treatment group was irrigated with 100 mL of GNS. After 20 days of cultivation, the lettuce leaves on the upper layer of soil were harvested and their fresh weights were weighed. The fresh weights of the various treatments were as follows: Figure 8 Compared to the control group without algae solution, the fresh weight of the treatment groups with 15 mL, 30 mL, and 50 mL of algae solution increased by 13.8%, 26.2%, and 43.1%, respectively. These results demonstrate that the Chlorella vulgaris of the present invention has significant fertilizer efficacy.

[0074] Using microalgae for flue gas carbon sequestration and emission reduction has many advantages: 1) Microalgae grows fast and has strong vitality. Its CO2 fixation capacity is 10-50 times that of ordinary forests, and its biomass yield is 4.5 times that of soybeans; 2) Microalgae can be cultivated on non-arable land or in seawater to fix carbon, so it will not cause changes in land properties, thereby minimizing related environmental impacts; 3) Microalgae can be grown and cultivated year-round and is suitable for flue gas emissions from coal-fired power plants that operate year-round.

[0075] The present invention has isolated and obtained a strain of Chlorella keslerae, which has good tolerance in flue gas with a wide concentration range, and grows well and fast, and is very suitable for direct use in carbon sequestration and emission reduction of flue gas from power plants; at the same time, the present invention has also found that the microalgae has good fertilizer effect, is suitable as a microalgae biofertilizer, and has good economic value. Based on the above findings, the present invention innovatively couples the carbon sequestration and emission reduction of microalgae in flue gas from power plants with the use of microalgae biofertilizer, greatly extending the ecological chain of the technology, effectively increasing the amount of carbon sequestration and emission reduction throughout the life cycle, while reducing the subsequent waste discharge and treatment of microalgae, reducing costs, and having very good economic feasibility.

[0076] The above description of the embodiments is intended to facilitate understanding and application of the present invention by those skilled in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made and the general principles described herein can be applied to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the embodiments described herein. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be considered within the scope of protection of the present invention.

Claims

1. Chlorella sp. HY1, deposited in China Center for Type Culture Collection with the accession number CCTCC NO: M 2025689.

2. Use of the Chlorella vulgaris described in claim 1 in carbon sequestration and emission reduction in power plant flue gas and in parallel production of biofertilizer.

3. The use according to claim 2, characterized in that: The Chlorella vulgaris is cultivated in the flue gas of a power plant.

4. A method for coupling carbon sequestration and emission reduction of power plant flue gas by microalgae with utilization of microalgae biofertilizer, characterized in that: include: 1) Cultivating the algae strain of claim 1 in power plant flue gas; and 2) Harvesting the algae cultured in step 1) and using it to prepare microalgae biofertilizer.

5. The method of coupling power plant flue gas microalgae carbon sequestration and emission reduction with microalgae biofertilizer utilization according to claim 4, characterized in that: In step 1), the carbon fixation efficiency of the algae strain is above 0.5 g / L / d.

6. The method of coupling power plant flue gas microalgae carbon sequestration and emission reduction with microalgae biofertilizer utilization according to claim 6, characterized in that: Step 2 includes compounding the harvested algae strains with other fertilizers to form microalgae biofertilizer, wherein the other fertilizers include inorganic fertilizers, organic fertilizers or bacterial biofertilizers.

7. The method of coupling power plant flue gas microalgae carbon sequestration and emission reduction with microalgae biofertilizer utilization according to claim 6, characterized in that: In step 2, the microalgae biofertilizer comprises an active microalgae fertilizer liquid product.

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