Microalgae strains having plant growth promoting properties and their uses

Abstract

The present application relates to a novel microalgae strain having plant growth promoting properties and its use. The novel Chlorella vulgaris CD02-3002 strain according to one aspect has a high growth rate and high photosynthetic efficiency when cultured in the presence of fermentation exhaust gas, and can effectively reduce exhaust gas caused by microbial fermentation. When the culture or culture supernatant of the strain is applied to plants, it has the effect of promoting plant growth and can be used as a plant fertilizer, so it can be usefully used as a new carbon reduction technology that is environmentally friendly and has high industrial applicability.

Description

[Technical field]

[0001] Cross-reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0125207 dated September 17, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present application relates to a novel microalgae strain having plant growth promoting activity and uses thereof. [Background technology]

[0003] As the scale of the bioindustry expands, it has become possible to produce a variety of products based on microbial fermentation technology, and in particular, the microbial fermentation industry has grown significantly with the recent growth of the white bio field. However, since fermentation is a process that basically emits carbon dioxide, the development of the microbial fermentation industry is accompanied by the problem of a significant increase in greenhouse gas emissions generated by fermentation. In addition, as the issue of climate change emerges worldwide, various efforts are being made to reduce greenhouse gases, which are pointed out as the main cause of climate change, and reducing greenhouse gases generated by microbial fermentation has become a major issue.

[0004] So far, technologies that can mainly suppress greenhouse gas emissions themselves and contribute to carbon reduction have been commercialized, but it is considered very difficult to reduce carbon dioxide emissions during the microbial fermentation process. In addition, the development of technologies that can directly capture and reduce greenhouse gases is still at a minimal level, and in particular, since carbon dioxide exists in the atmosphere at very low concentrations and is a stable substance with very low reactivity, it is difficult to develop a technology to reduce carbon dioxide that has already been emitted. In relation to this, a method using organisms capable of photosynthesis has been considered as one type of biological carbon reduction technology, but there is a problem that the profit structure other than the purpose of carbon reduction is unclear and it is difficult to apply to actual industries. Therefore, the reality is that it is necessary to develop a carbon reduction technology that can reduce carbon dioxide generated by microbial fermentation in an environmentally friendly manner and is also applicable to industry. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present application is to provide a Chlorella vulgaris strain CD02-3002, deposited under accession number KCTC14659BP, which has plant growth-promoting efficacy.

[0006] Another object of the present application is to provide a composition for promoting plant growth, comprising at least one selected from the group consisting of Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product.

[0007] Another object of the present application is to provide a fertilizer for plants comprising said plant growth promoting composition.

[0008] Another object of the present application is to provide a method for culturing the Chlorella vulgaris strain CD02-3002, which has been deposited under Accession No. KCTC14659BP and has a plant growth-promoting effect, comprising culturing the Chlorella vulgaris strain CD02-3002 in the presence of fermentation exhaust gas.

[0009] Another object of the present application is to provide a method for promoting plant growth, comprising the steps of: preparing a plant growth-promoting composition comprising one or more selected from the group consisting of Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product; and contacting the plant growth-promoting composition with a plant.

[0010] Another object of the present application is to provide a use of the Chlorella vulgaris CD02-3002 strain, deposited under Accession No. KCTC14659BP and having plant growth-promoting activity, for producing a plant fertilizer or for promoting plant growth.

[0011] Another object of the present application is to provide a use of a composition comprising any one or more selected from the group consisting of the Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product, for producing a plant fertilizer for promoting plant growth or for promoting plant growth. [Means for solving the problem]

[0012] Each description and embodiment disclosed in this application may be applied to each other description and embodiment. That is, all combinations of the various elements disclosed in this application belong to the scope of this application. In addition, the specific descriptions described below are not intended to limit the scope of this application. In addition, those skilled in the art will recognize or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific aspects of this application described in this application. In addition, such equivalents are intended to be included in this application.

[0013] One aspect provides a Chlorella vulgaris strain CD02-3002, deposited under accession number KCTC14659BP, having plant growth promoting activity.

[0014] The plant may be an Arabidopsis plant. For example, the Arabidopsis plant may be, but is not limited to, Arabidopsis thaliana.

[0015] As used herein, the term "plant growth" refers to the process by which a plant seed germinates and produces roots, stems, leaves, or otherwise gradually increases in size and weight, and the term "plant growth promotion" refers to promoting the germination of a plant seed or the increase in size and / or weight of a germinated plant.

[0016] The Chlorella vulgaris CD02-3002 strain may have an 18S rRNA base sequence of SEQ ID NO: 1, but is not limited thereto. For example, the Chlorella vulgaris CD02-3002 strain may have an 18S rRNA consisting of a base sequence showing 80% or more, 85% or more, 90% or more, 95% or more, 98% or more, or 99% or more sequence identity to the base sequence of SEQ ID NO: 1, but is not limited thereto.

[0017] In another aspect, there is provided a composition for promoting plant growth, comprising at least one selected from the group consisting of Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having plant growth-promoting activity; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product.

[0018] The Chlorella vulgaris CD02-3002 strain is as described above.

[0019] The "culture" of the strain refers to a product produced by culturing the strain, and may specifically be a culture broth containing the strain, and the "culture supernatant" may be a culture of the strain or a culture filtrate obtained by removing the strain from the culture broth. The "concentrate" may refer to a concentrate of the culture or culture supernatant. The "dried product" refers to a culture, culture supernatant or concentrate of the strain from which water has been removed, and may be, for example, a dried cell form of the strain, but is not limited thereto. The "crushed product" of the dried product refers to a product obtained by crushing the dried product from which water has been removed, and may be, for example, a dried cell powder of the strain, but is not limited thereto. The culture of the strain may be prepared by inoculating a culture medium with the strain and using a culture method known in the art, or may be prepared by a method including a step of culturing the strain in the presence of fermentation exhaust gas. The concentrate, dried product thereof or crushed product thereof can be prepared by a method for treating or drying microalgae or a culture thereof known in the art.

[0020] The plant may be a plant of the genus Arabidopsis. For example, the plant of the genus Arabidopsis may be, but is not limited to, Arabidopsis thaliana.

[0021] The plant growth promoting composition may contain a preservative, a stabilizer, a wetting agent or emulsifier, a cryoprotectant, or an excipient.

[0022] The preservatives, stabilizers, or excipients may be included in the composition in an effective amount sufficient to reduce deterioration of the composition.

[0023] As used herein, the term "deterioration in quality" may include a reduction in the number, activity, or a combination thereof of the Chlorella vulgaris strain CD02-3002 contained in a composition or the like.

[0024] For example, the composition may include an effective amount of a preservative, stabilizer, or excipient sufficient to reduce spoilage of the composition, thereby allowing the Chlorella vulgaris CD02-3002 strain to survive or remain active for a longer period of time within the composition as compared to the Chlorella vulgaris CD02-3002 strain present in nature.

[0025] The preservative, stabilizer, or excipient may be any preservative, stabilizer, or excipient commonly used in the art, as long as it can reduce the deterioration of the composition. For example, the stabilizer may be any one or more selected from the group consisting of alginate, sodium alginate, casein, sodium caseinate, cellulose, methylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, pectin, gelatin, gum arabic, xanthan gum, dextran, cyclodextrin, and starch.

[0026] The cryoprotectant may be present in the composition in an effective amount sufficient to reduce deterioration of the composition when the composition is in a lyophilized state, such that, unlike the Chlorella vulgaris CD02-3002 strain present in the natural state, the Chlorella vulgaris CD02-3002 strain may survive or remain active for a longer period of time in the lyophilized composition by including a cryoprotectant in an effective amount sufficient to reduce deterioration of the composition when the composition is in a lyophilized state.

[0027] The cryoprotectant may be any cryoprotectant commonly used in the art, as long as it is capable of reducing deterioration of the composition in a freeze-dried state. For example, the cryoprotectant may be any one or more selected from the group consisting of glycerol, ethylene glycol, propylene glycol, dimethyl sulfoxide (DMSO), glucose, trehalose, maltodextrin, dextrin, skim milk, and starch.

[0028] The composition can be added to plant fertilizers by dipping, spraying or mixing.

[0029] In yet another aspect, a plant fertilizer is provided that includes the plant growth promoting composition.

[0030] The plant growth promoting composition is as described above. The plant may be a plant of the genus Arabidopsis. For example, the plant of the genus Arabidopsis may be, but is not limited to, Arabidopsis thaliana.

[0031] The plant fertilizer may be prepared by a method commonly used in the art. For example, the plant fertilizer may further include an excipient or carrier commonly used in the art, and may be prepared in a typical plant fertilizer formulation known in the art.

[0032] The plant fertilizer may be an environmentally friendly fertilizer that can replace chemical fertilizers.

[0033] The plant fertilizer can be used to promote plant growth.

[0034] In still another aspect, there is provided a method for culturing the Chlorella vulgaris strain CD02-3002, which has been deposited under Accession No. KCTC14659BP and has plant growth-promoting activity, comprising a step of culturing the Chlorella vulgaris strain CD02-3002 in the presence of fermentation exhaust gas.

[0035] The Chlorella vulgaris CD02-3002 strain is as described above.

[0036] The fermentation exhaust gas may contain 0.5 to 20% (v / v) carbon dioxide. For example, the fermentation exhaust gas may contain 0.5 to 18% (v / v), 0.5 to 16% (v / v), 0.5 to 14% (v / v), 0.5 to 12% (v / v), 0.8 to 18% (v / v), 0.8 to 16% (v / v), 0.8 to 14% (v / v), or 0.8 to 12% (v / v) of carbon dioxide.

[0037] The fermentation exhaust gas may be generated by microbial fermentation. For example, the fermentation exhaust gas may contain carbon dioxide generated by microbial fermentation. The microorganism may include, without limitation, any microorganism that generates carbon dioxide during the fermentation or culture process.

[0038] The culturing step may be performed while supplying a fermentation exhaust gas to the fermenter. For example, the fermentation exhaust gas may be a gas generated by microbial fermentation that has been filtered and then supplied to the fermenter. The fermentation exhaust gas may be supplied to the fermenter at a rate of 0.001 to 1 vvm. For example, the fermentation exhaust gas may be supplied to the fermenter at a rate of 0.001-1 vvm, 0.001-0.7 vvm, 0.001-0.5 vvm, 0.001-0.3 vvm, 0.001-0.2 vvm, 0.005-1 vvm, 0.005-0.7 vvm, 0.005-0.5 vvm, 0.005-0.3 vvm, 0.005-0.2 vvm, 0.01-1 vvm, 0.01-0.7 vvm, 0.01-0.5 vvm, 0.01-0.3 vvm, or 0.01-0.2 vvm.

[0039] The culturing step may be carried out at a temperature of 20 to 40° C. For example, the culturing step may be carried out at a temperature of 20 to 30° C.

[0040] The culturing step may be performed in the presence of light. For example, the culturing step may be performed while irradiating a light source with an amount sufficient for the growth of the Chlorella vulgaris CD02-3002 strain. The light source may be, for example, but is not limited to, an LED light source.

[0041] The culturing step may be carried out for 30 days or less. For example, the culturing step may be carried out for 3 to 30 days, 3 to 20 days, 3 to 15 days, 3 to 12 days, or 3 to 10 days.

[0042] The culturing step can be carried out by known batch culture methods, continuous culture methods, fed-batch culture methods, etc., but is not limited thereto. The medium and other culture conditions used for culturing the Chlorella vulgaris strain CD02-3002 of the present application can be any medium used for culturing a general Chlorella vulgaris strain without any particular limitation, for example, BG-11 medium can be used. Specifically, the Chlorella vulgaris strain CD02-3002 of the present application can be cultured in a general medium containing a suitable carbon source, nitrogen source, phosphorus source, inorganic compound, amino acid and / or vitamin, while controlling the temperature, pH, etc. Specifically, the appropriate pH can be adjusted using a basic compound (e.g., sodium hydroxide, potassium hydroxide, or ammonia) or an acidic compound (e.g., phosphoric acid or sulfuric acid), but is not limited thereto.

[0043] In still another aspect, the present invention provides a method for promoting plant growth, comprising the steps of: preparing a composition for promoting plant growth, the composition comprising at least one selected from the group consisting of: Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product; and contacting the plant growth-promoting composition with a plant.

[0044] The Chlorella vulgaris CD02-3002 strain and the plant growth promoting composition are as described above.

[0045] The culture or culture supernatant of the Chlorella vulgaris CD02-3002 strain may be collected by a suitable method known in the art. The step of preparing the plant growth-promoting composition may be performed by a suitable method known in the art. For example, centrifugation, filtration, anion exchange chromatography, crystallization, HPLC, etc. may be used, and a purification step may be further included, and methods such as concentrating and drying microalgae or a culture thereof known in the art may be used.

[0046] The contacting step may be performed by treating soil, a plant, or a plant seed with the plant growth-promoting composition, for example, but is not limited to, spraying the plant growth-promoting composition onto leaves of a plant.

[0047] In another aspect, there is provided a use of the Chlorella vulgaris strain CD02-3002, deposited under Accession No. KCTC14659BP and having a plant growth promoting effect, for producing a plant fertilizer or for promoting plant growth.

[0048] In still another aspect, there is provided a use of a composition for producing a plant fertilizer for promoting plant growth or for promoting plant growth, the composition comprising one or more selected from the group consisting of Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product. Effect of the Invention

[0049] The novel Chlorella vulgaris CD02-3002 strain developed by Imon has a fast growth rate and high photosynthetic efficiency when cultured in the presence of fermentation exhaust gas, and can effectively reduce exhaust gas caused by microbial fermentation. When the culture or culture supernatant of the strain is applied to plants, it has the effect of promoting plant growth and can be used as a plant fertilizer, so it can be usefully used as a new carbon reduction technology that is environmentally friendly and has high industrial applicability. [Brief description of the drawings]

[0050] [Figure 1] This is a graph showing the results of measuring the dry cell weight (DCW) after culturing four types of Chlorella vulgaris strains. [Diagram 2] 1 is a graph showing the results of measuring the aboveground weight of Arabidopsis thaliana after treatment with dilutions of culture supernatants of DW, BG-11 liquid medium, Acadian 29, or four types of Chlorella vulgaris strains. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] The present invention will now be described in more detail with reference to examples. However, these examples are intended to illustratively illustrate one or more specific embodiments, and the scope of the present invention is not limited to these examples. EXAMPLES

[0052] Example 1. Isolation of novel wild-type green algae Samples were collected from a total of five river areas in Suwon City, Gyeonggi Province, South Korea, and microalgae belonging to the green algae were isolated using the direct plating technique.

[0053] Specifically, after collecting the samples, microalgae were isolated from them within 2 to 3 days, and samples that were found to have a greenish and spherical morphology through microscopic observation were placed in BG-11 solid medium for microbial isolation (1.5 g / L NaNO3, 40 mg / L K2HPO4, 75 mg / L MgSO4·7H2O, 36 mg / L CaCl2·2H2O, 6 mg / L citric acid·H2O, 6 mg / L ferric ammonium citrate, 1 mg / L Na2EDTA·2H2O, 20 mg / L Na2CO3, 2.86 mg / L H3BO3, 1.81 mg / L MnCl2·4H2O, 0.22 mg / L ZnSO4·7H2O, 0.39 mg / L Na2MoO4·2H2O, 0.079 mg / L The colonies were then smeared on a 15g / L agar plate containing 0.049mg / L CuSO4·5H2O, 0.049mg / L Co(NO3)2·6H2O, and 15g / L agar. The colonies were then subcultured on BG-11 solid medium containing antibiotic cocktail mix solutions (0~500mg / L streptomycin sulfate, 0~500mg / L ampicillin, and 0~500mg / L kanamycin sulfate) at different concentrations to isolate pure colonies.

[0054] Example 2. DNA sequence identification of isolated microalgae For molecular biological identification of the microalgae isolated in Example 1, the 18S rRNA sequence was analyzed.

[0055] Specifically, DNA was extracted from the isolated colonies, and PCR was then performed using primers for amplifying the 18S rRNA gene (Table 1).

[0056] [Table 1]

[0057] The PCR reaction was carried out by denaturing at 95°C for 5 minutes, denaturing at 95°C for 30 seconds, annealing at 55°C for 30 seconds, and polymerizing at 72°C for 2 minutes 35 times, followed by polymerization at 72°C for 5 minutes. The amplified reaction solution was used to analyze the base sequence, and a base sequence of approximately 1,565 bp in size was obtained (SEQ ID NO: 1). A BLAST search on NCBI (https: / / www.ncbi.nlm.nih.gov / ) confirmed that it had 99.68% homology with Chlorella vulgaris KMMCC FC-42 strain, and the isolated strain was named Chlorella vulgaris CD02-3002 and deposited with the Korean Collection for Type Cultures (KCTC), an international depository institution under the Budapest Treaty, on August 23, 2021, and was assigned the accession number KCTC14659BP.

[0058] Example 3. Confirmation of the growth potential of Chlorella vulgaris CD02-3002 strain under light culture conditions based on fermentation exhaust gas To confirm whether the isolated novel strain, Chlorella vulgaris CD02-3002, can grow under light culture conditions based on fermentation exhaust gas, its growth ability was compared with that of various Chlorella vulgaris strains.

[0059] The control strain was the Chlorella vulgaris UTEX265 strain provided by the UTEX Culture Collection of Algae at UT-Austin, and the comparative strains were the Chlorella vulgaris CD11-2001 and CD11-2003 strains isolated in the same manner as described in Example 1. Each strain was cultured in sterile BG-11 liquid medium (1.5 g / L NaNO3, 40 mg / L K2HPO4, 75 mg / L MgSO4·7H2O, 36 mg / L CaCl2·2H2O, 6 mg / L citric acid·H2O, 6 mg / L ferric ammonium citrate, 1 mg / L Na2EDTA·2H2O, 20 mg / L Na2CO3, 2.86 mg / L H3BO3, 1.81 mg / L MnCl2·4H2O, 0.22 mg / L ZnSO4·7H2O, 0.39 mg / L Na2MoO4·2H2O, 0.079 mg / L CuSO4·5H2O, 0.049 mg / L ZnSO4·5H2O, 0.05 mg / L Na2CO3·2H2O, 0.06 mg / L Na2MoO4·2H2O, 0.079 mg / L CuSO4·5H2O, 0.05 mg / L Na2CO3·2H2O, 0.06 ... The culture was then inoculated into 100 mL of Co(NO3)2·6H2O, and cultured for 4-7 days while being continuously irradiated with a LED light source and supplied with 1-10% (v / v) CO2 at 0.01-0.1 vvm. The culture was then inoculated into 900 mL of fresh sterilized BG-11 liquid medium and cultured for 3-5 days while being continuously irradiated with a LED light source, and during the culture period, fermentation exhaust gas was directly supplied to the culture at 0.01-0.5 vvm via an air filter. The fermentation exhaust gas was generated during fed-batch cultivation of Escherichia coli CJ181 (KFCC 10902) strain (US Patent Publication US2008 / 0299644 A1) in a 5L fermenter, maintaining a culture temperature of 30°C, a culture pH of 6.9-7.1 (pH adjusted with ammonia water), an aeration volume of 0.5-1.0 vvm, and an agitation speed of 500-700 rpm.

[0060] After the cultivation, 10 mL of each culture medium was filtered through a 0.45 μm filter and dried in an oven at 60°C for 24 hours. The dry cell weight (DCW) was calculated by calculating the difference between the weight of the filter before filtration and the weight of the filter containing the dried cells after filtration and drying.

[0061] As a result, it was confirmed that the Chlorella vulgaris CD02-3002 strain had a significantly higher dry cell weight than the provided Chlorella vulgaris strain (UTEX265) and other newly isolated Chlorella vulgaris strains (CD11-2001 and CD11-2003) as shown in Figure 1. This indicates that the Chlorella vulgaris CD02-3002 strain has the highest growth rate under light culture conditions based on fermentation exhaust gas compared to other Chlorella vulgaris strains.

[0062] Example 4. Confirmation of plant growth promoting effect of culture supernatant of Chlorella vulgaris CD02-3002 strain In order to confirm the plant growth promoting effect of the culture supernatant of Chlorella vulgaris CD02-3002 strain, the growth promotion effect was evaluated on Arabidopsis thaliana.

[0063] Specifically, wild-type Arabidopsis seeds were surface-sterilized in 70% ethanol for 1 minute and 1% NaOCl solution for 3 minutes, then washed with sterilized distilled water. Arabidopsis was stored in a refrigerator (4℃) for 2 days, planted in bed soil (Hannoh Farm Co., Ltd.), and cultivated in a 21℃ incubator for about a week under dark conditions with 12 hours of light and 12 hours of no light.

[0064] A total of four strains of Chlorella vulgaris, UTEX265, CD11-2001, CD02-3002, and CD11-2003, were inoculated into 200 mL of sterilized BG-11 liquid medium and cultured for 5-7 days at 25°C while irradiating with an LED light source and continuously supplying 1-10% (v / v) CO2 at 0.1 vvm. The cultured seed cultures were inoculated into 1.8 L of sterilized BG-11 liquid medium and cultured under the same conditions for up to 10 days. After the culture was completed, the cultures were centrifuged to obtain the culture supernatants of each strain.

[0065] To evaluate the plant growth promotion effect, cultivated Arabidopsis thaliana was treated with 10-1000 times diluted solutions of the culture supernatant of each strain at a level of 1mL / plant, and foliar fertilization was performed three times at four-day intervals. A control group was set up as a group treated with distilled water (DW), and comparison groups were added with the medium used for light culture of microalgae (BG-11 liquid medium) or a commercially available seaweed extract liquid fertilizer (Acadian 29). The aboveground fresh weight (aboveground weight) was measured as an index of Arabidopsis thaliana growth. The experiment was repeated on eight Arabidopsis plants for each test group, and the average and standard deviation of aboveground fresh weight were calculated and shown.

[0066] As a result, as shown in Figure 2, the other Chlorella vulgaris strains showed little or no growth promotion effect compared to the control group, while the Chlorella vulgaris CD02-3002 strain showed a significantly superior growth promotion effect, which was significantly superior to the commercial fertilizer Acadian 29.

[0067] From the above description, a person having ordinary skill in the art to which the present application pertains can understand that the present application can be implemented in other specific forms without changing its technical ideas or essential features. In this regard, it should be understood that the above described embodiments are illustrative and not limiting in all respects. The scope of the present application should be interpreted as including all modifications or alterations derived from the meaning and scope of the claims below and their equivalent concepts rather than the above detailed description.

[0068] [Accession number] Name of depository institution: Korea Comprehensive Biological Resource Center (KCTC) Accession number: KCTC14659BP Date of acceptance: 20210823 TIFF0007617313000002.tif238168

Claims

1. Chlorella vulgaris strain CD02-3002, deposited under accession number KCTC14659BP, has plant growth promoting activity.

2. A composition for promoting plant growth, comprising at least one selected from the group consisting of Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product.

3. A plant fertilizer comprising the plant growth promoting composition according to claim 2.

4. A method for culturing Chlorella vulgaris CD02-3002 strain, which has been deposited under Accession No. KCTC14659BP and has plant growth promoting activity, comprising a step of culturing the Chlorella vulgaris CD02-3002 strain in the presence of fermentation exhaust gas.

5. The method for culturing the Chlorella vulgaris CD02-3002 strain according to claim 4, wherein the fermentation exhaust gas contains 0.5 to 20% (v / v) carbon dioxide.

6. The method for culturing the Chlorella vulgaris CD02-3002 strain according to claim 4, wherein the fermentation exhaust gas is generated by microbial fermentation.

7. The method for culturing the Chlorella vulgaris CD02-3002 strain according to claim 4, wherein the culturing step is carried out at 20 to 40°C.

8. The method for culturing the Chlorella vulgaris CD02-3002 strain according to claim 4, wherein the culturing step is carried out for 30 days or less.

9. a step of preparing a composition for promoting plant growth, comprising at least one selected from the group consisting of Chlorella vulgaris CD02-3002 strain deposited under Accession No. KCTC14659BP and having a plant growth-promoting effect; a culture or culture supernatant of the strain; a concentrate of the culture or culture supernatant; a dried product of the culture, culture supernatant or concentrate; and a crushed product of the dried product; and A method for promoting plant growth comprising the step of contacting the plant with the plant growth promoting composition.

10. 10. The method for promoting plant growth according to claim 9, wherein the contacting step is carried out by treating soil, a plant, or a seed of a plant with the plant growth promoting composition.

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