Light-responsive composite culture medium and application thereof in plant cultivation
By using a light-responsive composite culture medium in a closed space, combined with carbon-fixing microorganisms, nitrogen-fixing microorganisms, and TiO2/CdS heterojunction nanomaterials, a carbon and nitrogen fixation system synergistically integrating photonanomaterials and microorganisms was constructed. This solved the problems of slow plant growth and low light energy conversion efficiency in closed spaces, and achieved a shortened plant growth cycle and increased yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV OF TECH
- Filing Date
- 2025-04-09
- Publication Date
- 2026-05-29
AI Technical Summary
In enclosed spaces, how can we improve the photosynthetic efficiency of plants, promote carbon and nitrogen cycles, increase plant growth rate and the sustainability of cultivation, especially in environments with low light energy conversion efficiency, and how can we apply photocatalysis technology to plant cultivation to provide energy support?
A photoresponsive composite culture medium is provided, comprising dipotassium hydrogen phosphate and potassium dihydrogen phosphate buffer and microspheres in the buffer. The microspheres are composed of carbon-fixing microorganisms, nitrogen-fixing microorganisms and TiO2/CdS heterojunction nanomaterials. Through photocatalysis, hydrogen storage and carbon and nitrogen fixation processes, a photocatalytic nanomaterial and microorganism synergistic carbon and nitrogen fixation system is constructed.
It significantly improved the plant growth cycle and yield, shortening the lettuce growth cycle to 20 days in a closed environment and increasing the fresh weight to 60g, improving carbon and nitrogen cycle efficiency and promoting healthy plant growth.
Abstract
Description
Technical Field
[0001] This invention relates to the field of culture medium technology, and in particular to a light-responsive composite culture medium and its application in plant cultivation. Background Technology
[0002] As humanity's exploration of extreme environments deepens, especially with the increasing demand for living and working in enclosed spaces such as space and the deep sea, plant cultivation in enclosed spaces has become a crucial technological issue. "Space botany" has emerged as a new and rapidly developing field.
[0003] One of the main challenges of enclosed space agriculture is maintaining healthy plant growth in environments with limited resources, light, gas, and water. Traditional plant cultivation techniques rely on external light sources and atmospheric carbon sources, which is not feasible in enclosed spaces, especially in environments like space stations where there is no sunlight and the air composition is unstable. Therefore, how to enhance the photosynthetic efficiency of plants and promote the absorption of carbon dioxide and nitrogen in enclosed environments has become a major technical challenge that scientists need to solve. In addition, the light energy conversion efficiency in enclosed spaces is low, with conventional photosynthetic systems achieving a light energy conversion rate of less than 5%. This not only affects the speed of plant growth but also restricts the sustainability and stability of plant cultivation.
[0004] Photocatalysis technology primarily utilizes nanomaterials, such as titanium dioxide (TiO2) and cadmium sulfide (CdS), to catalyze the splitting of water using light energy to produce hydrogen. Hydrogen is not only a clean energy source but also provides essential energy support for plant cultivation systems. How to apply the highly efficient catalytic capabilities of photocatalysis to plant cultivation in closed environments has become a pressing issue for researchers. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a light-responsive composite culture medium and its application in plant cultivation.
[0006] The specific technical solution of this invention is as follows:
[0007] In a first aspect, the present invention provides a light-responsive composite culture medium comprising a buffer solution composed of dipotassium hydrogen phosphate and potassium dihydrogen phosphate, and microspheres in the buffer solution, wherein the microspheres comprise carbon-fixing microorganisms, nitrogen-fixing microorganisms, and TiO2 / CdS heterojunction nanomaterials.
[0008] Preferably, the pH of the culture medium is 6.5 to 7.5.
[0009] Preferably, the amount of microspheres added is 0.4~1.0 g / L per liter of buffer solution.
[0010] Preferably, the carbon-fixing microorganism is *Cupriavidus necator*, and the nitrogen-fixing microorganism is *Clostridium pasteurellii*.
[0011] Preferably, the method for preparing the microspheres includes the following steps:
[0012] (1) Add Clostridium pasteurellium and cysteine to sodium alginate gel, mix well, and shape to obtain precursor particles;
[0013] (2) Mix Cupriavidus necator with hydrogen storage material and CO2 adsorption material, and coat it on the surface of precursor particles to obtain carbon and nitrogen fixation system precursor particles.
[0014] (3) The TiO2 / CdS material is added to the PDMS sol and stirred thoroughly. Then it is coated onto the surface of the carbon and nitrogen fixation system precursor particles to obtain the microspheres.
[0015] Preferably, the precursor particles have a particle size of 3-4 mm, the coating thickness in step (2) is 4-6 mm, and the coating thickness in step (3) is 1-3 mm.
[0016] Preferably, the culture medium also includes vegetable juice that provides trace elements.
[0017] Secondly, the present invention provides the application of the above-mentioned light-responsive composite culture medium in plant cultivation.
[0018] Furthermore, the present invention provides the application of the above-mentioned light-responsive composite culture medium for plant cultivation in a closed environment.
[0019] Compared with the prior art, the present invention has the following technical effects:
[0020] This invention constructs a photocatalytic carbon and nitrogen fixation system by forming microspheres from carbon-fixing microorganisms, nitrogen-fixing microorganisms, and TiO2 / CdS heterojunction nanomaterials. This system is then mixed with a buffer solution composed of dipotassium hydrogen phosphate and potassium dihydrogen phosphate to obtain a photoresponsive composite culture medium. This composite culture medium can improve carbon and nitrogen cycling efficiency through photocatalysis, hydrogen storage, and carbon and nitrogen fixation processes, thereby significantly enhancing plant growth cycle and yield. Experiments show that in a closed environment, the composite culture medium provided by this invention can shorten the growth cycle of lettuce to 20 days and increase the fresh weight to 60g after 20 days of growth. Detailed Implementation
[0021] The present invention will be further described below with reference to embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.
[0022] In this embodiment of the invention, the carbon-fixing microorganism Cupriavidus necator DSM 428 and the nitrogen-fixing microorganism Clostridium pasteurianum were both obtained from the German Microbial Culture Collection (Deutsche Sammlung von Mikroorganismen und Zellkulturen, DSM); the TiO2 / CdS heterojunction nanomaterial was prepared according to commonly used preparation methods in the art; and the PDMS breathable membrane was purchased from Shanghai Biomaterials Co., Ltd., and the product specification was medical grade.
[0023] In this embodiment of the invention, the hydrogen analyzer was purchased from Beijing Huihuang Instrument Co., Ltd., model: GC-7890, equipped with a hydrogen detection device; the CO2 concentration meter was purchased from Honeywell Corporation, USA, model: MH-Z19, used to accurately measure the carbon dioxide concentration in the gas reaction; the anaerobic culture medium was purchased from Sigma-Aldrich Corporation, USA, model: M9 minimal medium (used for culturing Cupriavidus necator); the hydrogen storage material LaNi5 was from the Institute of Metal Materials, Chinese Academy of Sciences, model: LaNi5 / LaNi5H5; and the CO2 adsorption material (activated carbon) was purchased from Zhejiang Fuda Technology Co., Ltd., model: AP-AC600.
[0024] In one embodiment, a light-responsive composite culture medium is provided, comprising a buffer solution composed of dipotassium hydrogen phosphate and potassium dihydrogen phosphate, and microspheres in the buffer solution, wherein the microspheres comprise carbon-fixing microorganisms, nitrogen-fixing microorganisms, and TiO2 / CdS heterojunction nanomaterials.
[0025] In one embodiment, the pH of the culture medium is 6.5 to 7.5.
[0026] In one embodiment, the amount of microspheres added is 0.4~1.0 g / L per liter of buffer solution.
[0027] In one embodiment, the carbon-fixing microorganism is *Cupriavidus necator*, and the nitrogen-fixing microorganism is *Clostridium pasteurellii*.
[0028] In one embodiment, a method for constructing carbon and nitrogen fixation microspheres based on the synergy of photonic nanomaterials and microorganisms is provided. Specifically, a method for preparing microspheres formed from the aforementioned carbon-fixing microorganisms, nitrogen-fixing microorganisms, and TiO2 / CdS heterojunction nanomaterials is provided, comprising the following steps:
[0029] (1) Add Clostridium pasteurellium and cysteine to sodium alginate gel, mix well, and shape to obtain precursor particles;
[0030] (2) Mix Cupriavidus necator with hydrogen storage material and CO2 adsorption material, and coat it on the surface of precursor particles to obtain carbon and nitrogen fixation system precursor particles.
[0031] (3) The TiO2 / CdS material is added to the PDMS sol and stirred thoroughly. Then it is coated onto the surface of the carbon and nitrogen fixation system precursor particles to obtain the carbon and nitrogen fixation microspheres.
[0032] The preparation method of the TiO2 / CdS material is as follows: TiO2 sol and CdS solution are mixed, reacted, precipitated, and the solvent is removed to obtain TiO2 / CdS material.
[0033] The precursor particles have a particle size of 3-4 mm.
[0034] In step (2), the thickness of the wrapping is 4~6 mm.
[0035] In step (3), the thickness of the wrapping is 1~3 mm.
[0036] This invention constructs a photocatalytic carbon and nitrogen fixation system by forming microspheres from carbon-fixing microorganisms, nitrogen-fixing microorganisms, and TiO2 / CdS heterojunction nanomaterials. This system is then mixed with a buffer solution composed of dipotassium hydrogen phosphate and potassium dihydrogen phosphate to obtain a photoresponsive composite culture medium. This composite culture medium can improve carbon and nitrogen cycling efficiency through photocatalysis, hydrogen storage, and carbon and nitrogen fixation processes, thereby significantly enhancing plant growth cycle and yield. Experiments show that in a closed environment, the composite culture medium provided by this invention can shorten the growth cycle of lettuce to 20 days and increase the fresh weight to 60g after 20 days of growth.
[0037] More specifically, the following embodiments will be described further.
[0038] Example 1
[0039] A light-responsive composite culture medium is provided, and its preparation method includes the following steps:
[0040] (1) Cultivation of carbon-fixing microorganisms:
[0041] Add 0.5 L of LB liquid medium to the reaction flask, inoculate Cupriavidus necator into the LB medium at a volume ratio of 3%, and introduce hydrogen and carbon dioxide into the reaction flask at a volume ratio of 1:1. Maintain the culture temperature at 30℃ and the pH of the medium at 7, and continue to culture for 48 hours to obtain Cupriavidus necator bacterial culture.
[0042] (2) Cultivation of nitrogen-fixing microorganisms:
[0043] Add 0.5 L of anaerobic culture medium (containing 50 mmol / L cysteine) to the reaction flask. Ensure an anaerobic environment by replacing the air in the medium with nitrogen. Inoculate *Clostridium pasteurianum* at a volume ratio of 3% into the medium and incubate for 48 hours to obtain a *Clostridium pasteurianum* bacterial suspension. Samples were taken every 4 hours during the incubation period to measure changes in ammonium salt concentration.
[0044] (3) Preparation of TiO2 / CdS heterojunction nanomaterials:
[0045] TiO2 (titanium dioxide) sol was mixed with a 0.1 mol / L CdS solution (cadmium sulfide solution) at a 1:1 molar ratio and reacted for 10 hours. Calcium chloride was used as a precipitant to obtain a white precipitate. The precipitate was placed in a flask and washed three times with deionized water to remove the solvent, yielding the TiO2 / CdS material.
[0046] (4) Preparation of nanocomposite microspheres with a three-layer structure:
[0047] Using the sol-gel method, sodium alginate gel and Clostridium pasteurianum bacterial solution were mixed at a 1:1 mass ratio, with 50 mmol / L cysteine added to stabilize the reduction potential and ensure nitrogenase activity. The mixture was thoroughly stirred and then dropped into a silicone mold to form a 3 mm thick inner layer.
[0048] The Cupriavidus necator bacterial solution was mixed with hydrogen storage material (LaNi5) and CO2 adsorption material (activated carbon) in a mass ratio of 2:2:1, and then coated into an inner layer to obtain a middle layer with a thickness of 5 mm.
[0049] The TiO2 / CdS material obtained in step (3) is added to the PDMS sol. The amount of TiO2 / CdS material added can be increased as needed. In this step, it is added at a mass ratio of 1:10. After stirring thoroughly, it is wrapped onto the middle layer surface, heated to 80°C, and dried to obtain the outer layer formed by the TiO2 / CdS heterojunction nanomaterial wrapped by the PDMS breathable membrane. The outer layer thickness is 2 mm, thus obtaining a nanocomposite microsphere with a three-layer structure.
[0050] (5) Prepare a mixture of dipotassium hydrogen phosphate (KH2PO4) and potassium dihydrogen phosphate (K2HPO4), and adjust the pH to 7.0. Each liter of buffer solution contains 1 g of dipotassium hydrogen phosphate and 2 g of potassium dihydrogen phosphate to ensure that the plants can obtain the required phosphorus and potassium elements.
[0051] (6) Collect fresh lettuce waste juice from the vegetable processing plant, filter and remove solid impurities, and add it to the mixture obtained in step (5) to obtain the culture medium substrate. Add 10 mL of lettuce waste juice to each liter of mixture to provide the trace elements and organic matter required for plant growth.
[0052] (7) Add the nanocomposite microspheres prepared in step (4) to the culture medium matrix. The amount added is based on the microspheres being fully immersed in the matrix liquid. Specifically, each liter of culture medium matrix contains 0.5 g of nanocomposite microspheres to obtain a photoresponsive composite culture medium.
[0053] Comparative Example 1
[0054] A composite culture medium is provided, the preparation method of which differs from that of Example 1 in that the microspheres do not contain a middle layer. It is prepared according to the following steps:
[0055] (1) Cultivation of nitrogen-fixing microorganisms:
[0056] Add 0.5 L of anaerobic culture medium (containing 50 mmol / L cysteine) to the reaction flask. Ensure an anaerobic environment by replacing the air in the medium with nitrogen. Inoculate *Clostridium pasteurianum* at a volume ratio of 3% into the medium and incubate for 48 hours to obtain a *Clostridium pasteurianum* bacterial suspension. Samples were taken every 4 hours during the incubation period to measure changes in ammonium salt concentration.
[0057] (2) Preparation of TiO2 / CdS heterojunction nanomaterials:
[0058] TiO2 (titanium dioxide) sol was mixed with a 0.1 mol / L CdS solution (cadmium sulfide solution) at a 1:1 molar ratio and reacted for 10 hours. Calcium chloride was used as a precipitant to obtain a white precipitate. The precipitate was placed in a flask and washed three times with deionized water to remove the solvent, yielding the TiO2 / CdS material.
[0059] (3) Preparation of nanocomposite microspheres:
[0060] Using the sol-gel method, sodium alginate gel and Clostridium pasteurianum bacterial solution were mixed at a 1:1 mass ratio, with 50 mmol / L cysteine added to stabilize the reduction potential and ensure nitrogenase activity. The mixture was thoroughly stirred and then dropped into a silicone mold to form a 3 mm thick inner layer.
[0061] The TiO2 / CdS material obtained in step (2) is added to PDMS sol. The mass ratio of TiO2 / CdS material to PDMS sol is 1:10. The mixture is stirred thoroughly and then wrapped onto the inner surface. The mixture is heated to 80°C and dried to obtain an outer layer of TiO2 / CdS heterojunction nanomaterial wrapped in PDMS breathable membrane. The outer layer thickness is 2 mm, thus obtaining nanocomposite microspheres.
[0062] (4) Prepare a mixture of dipotassium hydrogen phosphate (KH2PO4) and potassium dihydrogen phosphate (K2HPO4), and adjust the pH to 7.0. Each liter of buffer solution contains 1 g of dipotassium hydrogen phosphate and 2 g of potassium dihydrogen phosphate to ensure that the plants can obtain the required phosphorus and potassium elements.
[0063] (5) Collect fresh lettuce waste juice from the vegetable processing plant, filter and remove solid impurities, and add it to the mixture obtained in step (4) to obtain the culture medium substrate. Add 10 mL of lettuce waste juice to each liter of mixture to provide the trace elements and organic matter required for plant growth.
[0064] (6) Add the nanocomposite microspheres prepared in step (3) to the culture medium matrix. The amount added is based on the microspheres being fully immersed in the matrix liquid. Specifically, each liter of culture medium matrix contains 0.5 g of nanocomposite microspheres to obtain a composite culture medium.
[0065] Comparative Example 2
[0066] A composite culture medium is provided, the preparation method of which differs from that of Example 1 in that the microspheres do not have an inner layer. It is prepared according to the following steps:
[0067] (1) Cultivation of carbon-fixing microorganisms:
[0068] Add 0.5 L of LB liquid medium to the reaction flask, inoculate Cupriavidus necator into the LB medium at a volume ratio of 3%, and introduce hydrogen and carbon dioxide into the reaction flask at a volume ratio of 1:1. Maintain the culture temperature at 30℃ and the pH of the medium at 7, and continue to culture for 48 hours to obtain Cupriavidus necator bacterial culture.
[0069] (2) Preparation of TiO2 / CdS heterojunction nanomaterials:
[0070] TiO2 (titanium dioxide) sol was mixed with a 0.1 mol / L CdS solution (cadmium sulfide solution) at a 1:1 molar ratio and reacted for 10 hours. Calcium chloride was used as a precipitant to obtain a white precipitate. The precipitate was placed in a flask and washed three times with deionized water to remove the solvent, yielding the TiO2 / CdS material.
[0071] (3) Preparation of nanocomposite microspheres:
[0072] Using the sol-gel method, sodium alginate gel and Cupriavidus necator bacterial solution were mixed at a mass ratio of 1:1. Then, LaNi5 and activated carbon were added at a mass ratio of 2:2:1 to Cupriavidus necator bacterial solution, hydrogen storage material (LaNi5), and CO2 adsorption material (activated carbon). The mixture was stirred thoroughly and then dropped into a silicone mold to form an inner layer with a thickness of 5 mm.
[0073] The TiO2 / CdS material obtained in step (2) is added to PDMS sol. The mass ratio of TiO2 / CdS material to PDMS sol is 1:10. The mixture is stirred thoroughly and then wrapped onto the inner surface. The mixture is heated to 80°C and dried to obtain an outer layer of TiO2 / CdS heterojunction nanomaterial wrapped in PDMS breathable membrane. The outer layer thickness is 2 mm, thus obtaining nanocomposite microspheres.
[0074] (4) Prepare a mixture of dipotassium hydrogen phosphate (KH2PO4) and potassium dihydrogen phosphate (K2HPO4), and adjust the pH to 7.0. Each liter of buffer solution contains 1 g of dipotassium hydrogen phosphate and 2 g of potassium dihydrogen phosphate to ensure that the plants can obtain the required phosphorus and potassium elements.
[0075] (5) Collect fresh lettuce waste juice from the vegetable processing plant, filter and remove solid impurities, and add it to the mixture obtained in step (4) to obtain the culture medium substrate. Add 10 mL of lettuce waste juice to each liter of mixture to provide the trace elements and organic matter required for plant growth.
[0076] (6) Add the nanocomposite microspheres prepared in step (3) to the culture medium matrix. The amount added is based on the microspheres being fully immersed in the matrix liquid. Specifically, each liter of culture medium matrix contains 0.5 g of nanocomposite microspheres to obtain a composite culture medium.
[0077] Comparative Example 3
[0078] A composite culture medium is provided, the preparation method of which differs from that of Example 1 in that the microspheres do not contain an inner layer and a middle layer. It is prepared according to the following steps:
[0079] (1) Preparation of TiO2 / CdS heterojunction nanomaterials:
[0080] TiO2 (titanium dioxide) sol was mixed with a 0.1 mol / L CdS solution (cadmium sulfide solution) at a 1:1 molar ratio and reacted for 10 hours. Calcium chloride was used as a precipitant to obtain a white precipitate. The precipitate was placed in a flask and washed three times with deionized water to remove the solvent, yielding the TiO2 / CdS material.
[0081] (2) Preparation of composite microspheres:
[0082] TiO2 / CdS material was added to PDMS sol at a mass ratio of 1:10. The mixture was stirred thoroughly, heated to 80°C, and dried to obtain TiO2 / CdS heterojunction nanoparticles with a diameter of 2 mm encapsulated in a PDMS breathable membrane, thus preparing nanocomposite microspheres.
[0083] (3) Prepare a mixture of dipotassium hydrogen phosphate (KH2PO4) and potassium dihydrogen phosphate (K2HPO4), and adjust the pH to 7.0. Each liter of buffer solution contains 1 g of dipotassium hydrogen phosphate and 2 g of potassium dihydrogen phosphate to ensure that the plants can obtain the required phosphorus and potassium elements.
[0084] (4) Collect fresh lettuce waste juice from the vegetable processing plant, filter and remove solid impurities, and add it to the mixture obtained in step (3) to obtain the culture medium substrate. Add 10 mL of lettuce waste juice to each liter of mixture to provide the trace elements and organic matter required for plant growth.
[0085] (5) Add the nanocomposite microspheres prepared in step (2) to the culture medium matrix. The amount added is based on the microspheres being fully immersed in the matrix liquid. Specifically, each liter of culture medium matrix contains 0.5 g of nanocomposite microspheres to obtain a composite culture medium.
[0086] Comparative Example 4
[0087] A composite culture medium is provided, the preparation method of which differs from that of Example 1 in that the microspheres do not have an outer layer. It is prepared according to the following steps:
[0088] (1) Cultivation of carbon-fixing microorganisms:
[0089] Add 0.5 L of LB liquid medium to the reaction flask, inoculate Cupriavidus necator into the LB medium at a volume ratio of 3%, and introduce hydrogen and carbon dioxide into the reaction flask at a volume ratio of 1:1. Maintain the culture temperature at 30℃ and the pH of the medium at 7, and continue to culture for 48 hours to obtain Cupriavidus necator bacterial culture.
[0090] (2) Cultivation of nitrogen-fixing microorganisms:
[0091] Add 0.5 L of anaerobic culture medium (containing 50 mmol / L cysteine) to the reaction flask. Ensure an anaerobic environment by replacing the air in the medium with nitrogen. Inoculate *Clostridium pasteurianum* at a volume ratio of 3% into the medium and incubate for 48 hours to obtain a *Clostridium pasteurianum* bacterial suspension. Samples were taken every 4 hours during the incubation period to measure changes in ammonium salt concentration.
[0092] (3) Preparation of composite microspheres:
[0093] Using the sol-gel method, sodium alginate gel and Clostridium pasteurianum bacterial solution were mixed at a 1:1 mass ratio, with 50 mmol / L cysteine added to stabilize the reduction potential and ensure nitrogenase activity. The mixture was thoroughly stirred and then dropped into a silicone mold to form a 3 mm thick inner layer.
[0094] The Cupriavidus necator bacterial solution was mixed with hydrogen storage material (LaNi5) and CO2 adsorption material (activated carbon) in a mass ratio of 2:2:1, coated with an inner layer, and shaped to obtain an outer layer with a thickness of 5 mm, thus obtaining composite microspheres.
[0095] (4) Prepare a mixture of dipotassium hydrogen phosphate (KH2PO4) and potassium dihydrogen phosphate (K2HPO4), and adjust the pH to 7.0. Each liter of buffer solution contains 1 g of dipotassium hydrogen phosphate and 2 g of potassium dihydrogen phosphate to ensure that the plants can obtain the required phosphorus and potassium elements.
[0096] (5) Collect fresh lettuce waste juice from the vegetable processing plant, filter and remove solid impurities, and add it to the mixture obtained in step (4) to obtain the culture medium substrate. Add 10 mL of lettuce waste juice to each liter of mixture to provide the trace elements and organic matter required for plant growth.
[0097] (6) Add the composite microspheres prepared in step (3) to the culture medium matrix. The amount added is based on the microspheres being fully immersed in the matrix liquid. Specifically, each liter of culture medium matrix contains 0.5 g of nano-composite microspheres to obtain a composite culture medium.
[0098] Plant cultivation
[0099] Soak lettuce seeds in distilled water for 4 hours, then gently pat them dry with paper towels to ensure no moisture remains on the seed surface. The treated lettuce seeds were then evenly sown in the composite culture medium provided in Example 1 and Comparative Examples 1, 2, and 3, and placed in a sealed container containing a 1:1 volume ratio of nitrogen and carbon dioxide. The container was then placed in a light incubator at 25°C, with a light intensity of 100 μmol·m⁻²·s⁻¹ and a 12-hour / day light cycle. Plant growth was regularly monitored, including leaf number, plant height, and fresh weight, and data were recorded at different time points. The fresh weight (g) of the lettuce was recorded on day 21 of the growth cycle, starting from day 1 (as shown in Table 1).
[0100] Table 1
[0101] Fresh weight (g) Example 1 67 Comparative Example 1 44 Comparative Example 2 41 Comparative Example 3 40 Comparative Example 4 36
[0102] As shown in Table 1, the composite culture medium containing carbon and nitrogen fixation microspheres based on photocatalytic nanomaterials and microbial synergy provided in Example 1 of this invention can significantly increase the fresh weight of lettuce. Data shows that compared to the fresh weight of the culture medium without microbial synergy, the fresh weight of lettuce increased from 40g to 60g, a 50% increase. This indicates that microbial synergy with photocatalytic nanomaterials can effectively increase the nutrients that plants can absorb in the composite culture medium, effectively promoting plant growth and increasing yield. Comparative analysis of Comparative Example 4 and Example 1 shows that the presence of the photocatalytic material TiO2 / CdS can more effectively promote plant growth. This is because the photocatalytic material can effectively regulate the micro-oxygen environment through oxygen permeation, helping plants better adapt to the growth needs in enclosed spaces.
[0103] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.
[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.
Claims
1. A light-responsive composite culture medium, characterized in that: The buffer solution comprises dipotassium hydrogen phosphate and potassium dihydrogen phosphate, and microspheres within the buffer solution. The microspheres include carbon-fixing microorganisms *Cupriavidus necator*, nitrogen-fixing microorganisms *Clostridium pasteurellii*, and TiO2 / CdS heterojunction nanomaterials, wherein: The pH of the composite culture medium is 6.5-7.5, and the amount of microspheres added is 0.4-1.0 g / L per liter of buffer solution. The preparation method of the microspheres includes the following steps: (1) Sodium alginate gel and Clostridium pasteurianum bacterial solution were mixed at a mass ratio of 1:1, and 50 mmol / L cysteine was added. The mixture was stirred and shaped to obtain precursor particles. (2) The Cupriavidus necator bacterial solution was mixed with LaNi5 and activated carbon in a mass ratio of 2:2:1, coated on the surface of the precursor particles, and shaped to obtain the precursor particles of the carbon and nitrogen fixation system. (3) TiO2 / CdS heterojunction nanomaterials were added to PDMS sol at a mass ratio of 1:10, mixed well and then coated onto the surface of carbon and nitrogen fixation system precursor particles to prepare nanocomposite microspheres with a three-layer structure.
2. The light-responsive composite culture medium as described in claim 1, characterized in that: The precursor particles have a particle size of 3-4 mm, the coating thickness in step (2) is 4-6 mm, and the coating thickness in step (3) is 1-3 mm.
3. The light-responsive composite culture medium as described in claim 1, characterized in that: The culture medium also includes vegetable juice that provides trace elements.
4. The application of the light-responsive composite culture medium as described in any one of claims 1 to 3 in plant cultivation.
5. The application of the light-responsive composite culture medium as described in any one of claims 1 to 3 for plant cultivation in a closed environment.