Dietzia alkaliphila strain GD-1 and its application in carbon fixation and phosphate solubilization

Abstract

The present invention relates to the technical field of microbial carbon fixation, in particular to a strain of Dietzia natronolimnaea GD-1 and its application in carbon fixation and phosphorus solubilization. The present invention provides a strain of Dietzia natronolimnaea GD-1 with a preservation number of CGMCC No. 31728. The Dietzia natronolimnaea GD-1 provided by the present invention is a carbon-fixing bacterium isolated from the soil between fixed plates in a salinized photovoltaic field area, having the ability to fix atmospheric carbon dioxide. At the same time, it has the ability to dissolve phosphorus, providing strain resources for enhancing the carbon sequestration and emission reduction capacity of salinized soil, providing technical support for in-depth understanding of the microbial regulation process of the occurrence form of nutrients in salinized soil, laying a foundation for proposing soil microbial improvement techniques in photovoltaic field areas, and promoting the high-quality development of the photovoltaic industry in fragile salinized areas.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial carbon fixation, and particularly to a Dietzia natronolimnaea GD-1 and its application in carbon fixation and phosphorus solubilization. Background Art

[0002] The development of new energy has become the core approach to addressing climate change. However, more than 80% of China's new energy is distributed in vulnerable areas (such as saline-alkali lands), and there is an urgent need to explore a new model for the organic integration of energy, ecological restoration, and the development of characteristic industries. Existing research has shown that functional microorganisms such as nitrogen-fixing bacteria and cellulose-degrading bacteria play an important role in improving saline-alkali lands, restoring soil physical and chemical properties, and ecological environment. Enhancing the potential of soil carbon sequestration and sink is an urgent need to restore the ecological functions of saline-alkali lands and mitigate climate change. However, research on the isolation and screening of soil carbon-fixing microorganisms and their carbon-fixing abilities is still lacking, and relevant research on the precise identification and screening of soil carbon-fixing microorganisms in photovoltaic fields of saline-alkali lands is even more scarce. Therefore, isolating and screening efficient carbon-fixing native functional microorganisms in photovoltaic fields of saline-alkali lands has important potential application value for stimulating and enhancing the synergistic benefits of native microorganisms in improving soil and carbon sequestration and sink. Summary of the Invention

[0003] To solve the above problems, the present invention provides a Dietzia natronolimnaea GD-1 and its application in carbon fixation and phosphorus solubilization. The Dietzia natronolimnaea GD-1 provided by the present invention has the ability of carbon fixation and at the same time has the ability of phosphorus solubilization, which is of great significance for enhancing the potential of soil carbon sequestration and sink, promoting the high-quality development of the photovoltaic industry in saline-alkali vulnerable areas, and alleviating global warming.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a Dietzia natronolimnaea GD-1 with a preservation number of CGMCC No. 31728.

[0006] The present invention provides a carbon-fixing bacterial agent comprising the Dietzia natronolimnaea GD-1 described in the above technical solution.

[0007] Preferably, the OD 600 value of Dietzia natronolimnaea GD-1 in the carbon-fixing bacterial agent is ≥ 0.6.

[0008] The present invention provides a preparation method of the carbon-fixing bacterial agent described in the above technical solution, comprising the following steps:

[0009] Inoculate the Dietzia natronolimnaea GD-1 described in the above technical solution into a culture medium for cultivation to obtain the carbon-fixing bacterial agent; the culture medium is a culture medium containing a carbon source or a culture medium without a carbon source.

[0010] Preferably, the culture medium further comprises an electron donor; the electron donor comprises sodium nitrite and / or sodium thiosulfate.

[0011] Preferably, the carbon source-free culture medium comprises components in the following concentrations: 0.5 g / L of Na2HPO4, 0.5 g / L of KH2PO4, 0.3 g / L of MgSO4, 0.2 g / L of CaCl2, 0.5 g / L of NH4Cl, 0.25 g / L of NaNO3, 0.4 g / L of NaCl, 10 mL / L of trace element solution; the trace element solution comprises components in the following concentrations: 0.3 g / L of FeCl2, 0.3 g / L of FeSO4·7H2O, 0.15 g / L of MnSO4·H2O, 0.25 g / L of ZnSO4·7H2O, 0.2 g / L of CoCl2; the pH value of the carbon source-free culture medium is 7.0 - 7.4.

[0012] Preferably, the carbon source-containing culture medium is prepared by adding a carbon source to the carbon source-free culture medium; the added carbon source comprises: sodium carbonate and / or sodium bicarbonate.

[0013] The present invention provides the application of Dietzia alkalilacus GD-1 described in the above technical solution, or the carbon-fixing bacterium agent described in the above technical solution, or the carbon-fixing bacterium agent prepared by the preparation method described in the above technical solution in carbon fixation and / or dissolution of insoluble inorganic phosphorus, and the carbon source for carbon fixation comprises an inorganic carbon source.

[0014] Preferably, the inorganic carbon source comprises one or more of carbon dioxide, sodium bicarbonate and sodium carbonate.

[0015] Preferably, the insoluble inorganic phosphorus comprises calcium phosphate.

[0016] Beneficial effects:

[0017] The present invention provides a strain of Dietzia alkalilacus GD-1 with a preservation number of CGMCC No. 31728. The Dietzia alkalilacus GD-1 provided by the present invention is a carbon-fixing bacterium isolated from the soil between fixed plates in a salinized photovoltaic field area, has the ability to fix carbon dioxide, and at the same time has the ability to dissolve phosphorus, providing strain resources for enhancing the carbon sequestration and emission reduction capacity of salinized soil, providing technical support for in-depth understanding of the microbial regulation process of the occurrence form of nutrients in salinized soil, laying a foundation for proposing soil microbial improvement technologies in photovoltaic field areas, and promoting the high-quality development of the photovoltaic industry in salinized vulnerable areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments.

[0019] Figure 1 Morphological diagram of the cells of the carbon-fixing bacterium Dietzia natronolimnaea GD-1;

[0020] Figure 2 Colony characteristic diagram of the carbon-fixing bacterium Dietzia natronolimnaea GD-1;

[0021] Figure 3 Phylogenetic tree of the 16S rRNA gene of the carbon-fixing bacterium Dietzia natronolimnaea GD-1;

[0022] Figure 4 Determination results of the RubisCO enzyme activity of the carbon-fixing bacterium Dietzia natronolimnaea GD-1;

[0023] Figure 5 Determination results of the carbon fixation ability of the carbon-fixing bacterium Dietzia natronolimnaea GD-1 under different conditions;

[0024] Figure 6 Carbon fixation pathway of the carbon-fixing bacterium Dietzia natronolimnaea GD-1;

[0025] Figure 7 Determination results of the available phosphorus content after the carbon-fixing bacterium Dietzia natronolimnaea GD-1 is cultured in a liquid medium containing insoluble phosphate salts.

[0026] Biological deposit description

[0027] Dietzia natronolimnaea GD-1, classified and named as Dietzia natronolimnaea, was deposited in the China General Microbiological Culture Collection Center (CGMCC) on August 23, 2024. The deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit number is CGMCC No. 31728. Detailed implementation manners

[0028] The present invention provides a strain of Dietzia natronolimnaea GD-1 with a deposit number of CGMCC No. 31728. The Dietzia natronolimnaea GD-1 provided by the present invention is a carbon-fixing bacterium isolated from the soil between the fixed plates in a salinized photovoltaic field. The cell morphology is short rod-shaped ( Figure 1 ), and the colonies it produces on the solid medium are small, round, orange-red, opaque, with a smooth and viscous surface, neat edges, and low convexity ( Figure 2 ). It has the ability to fix carbon dioxide. At the same time, it has the ability to dissolve phosphorus and can maintain a good growth rate and carbon fixation ability in a very low-nutrient salt medium. Adding inorganic carbon sources (sodium carbonate, sodium bicarbonate) and / or electron donors (sodium nitrite, sodium thiosulfate) can improve its growth rate, thereby improving its carbon fixation and phosphorus dissolution abilities, which is of great significance for enhancing the potential of soil carbon sequestration and sink, promoting the high-quality development of the photovoltaic industry in salinized vulnerable areas, and alleviating global warming.

[0029] Based on the above advantages, the present invention provides a carbon-fixing bacterial agent, which includes Dietzia alkaliphila GD-1 described in the above technical solution.

[0030] As an embodiment, the OD value of Dietzia alkaliphila GD-1 in the carbon-fixing bacterial agent 600 ≥0.6.

[0031] The present invention provides a preparation method of the carbon-fixing bacterial agent described in the above technical solution, including the following steps:

[0032] Inoculate Dietzia alkaliphila GD-1 described in the above technical solution into a culture medium for cultivation to obtain the carbon-fixing bacterial agent; the culture medium is a culture medium containing a carbon source or a culture medium without a carbon source.

[0033] As an embodiment, the culture medium further includes an electron donor; the electron donor includes sodium nitrite and / or sodium thiosulfate. The electron donor can improve the growth rate of Dietzia alkaliphila GD-1.

[0034] As an embodiment, the culture medium without a carbon source includes components with the following concentrations: Na2HPO4 0.5 g / L, KH2PO4 0.5 g / L, MgSO4 0.3 g / L, CaCl2 0.2 g / L, NH4Cl 0.5 g / L, NaNO3 0.25 g / L, NaCl 0.4 g / L, trace element solution 10 mL / L; the trace element solution includes components with the following concentrations: FeCl2 0.3 g / L, FeSO4·7H2O 0.3 g / L, MnSO4·H2O 0.15 g / L, ZnSO4·7H2O 0.25 g / L, CoCl2 0.2 g / L. Dietzia alkaliphila GD-1 of the present invention can utilize carbon dioxide in the atmosphere, so it can reproduce and fix carbon dioxide in the atmosphere in a culture medium without a carbon source.

[0035] As an embodiment, the culture medium containing a carbon source is prepared by adding a carbon source to the culture medium without a carbon source; the carbon source of the culture medium containing a carbon source includes: sodium carbonate and / or sodium bicarbonate. Exogenous addition of an inorganic carbon source can improve the growth rate of Dietzia alkaliphila GD-1.

[0036] As an embodiment, the cultivation time is 5 to 7 days; the cultivation temperature is 28°C.

[0037] The present invention provides the application of Dietzia alkaliphila GD-1 described in the above technical solution or the carbon-fixing bacterial agent described in the above technical solution or the carbon-fixing bacterial agent prepared by using the preparation method described in the above technical solution in carbon fixation and / or dissolution of insoluble inorganic phosphorus, and the carbon source for carbon fixation includes an inorganic carbon source.

[0038] As an implementation manner, the inorganic carbon source includes one or more of carbon dioxide, sodium bicarbonate, and sodium carbonate. The Dietzia natronolimnaea GD-1 provided by the present invention has higher carbon fixation potential in a soil environment with a relatively high carbonate content, which helps to develop the application of Dietzia natronolimnaea GD-1 in special environments (such as soda saline-alkali land).

[0039] As an implementation manner, the insoluble inorganic phosphorus can be calcium phosphate. The Dietzia natronolimnaea GD-1 provided by the present invention can dissolve insoluble inorganic phosphorus into soluble phosphate.

[0040] To further illustrate the present invention, the following describes in detail a strain of Dietzia natronolimnaea GD-1 provided by the present invention and its application in carbon fixation and phosphorus dissolution with reference to the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0041] Example 1 Isolation and Identification of Carbon-Fixing Bacterium Dietzia natronolimnaea GD-1

[0042] Taking the soil between the fixed plates in the Daqing salinized photovoltaic field area as the target soil, the specific screening scheme is as follows:

[0043] 1. Collect the soil at a depth of 0 - 20 cm. Take 10.0 g of the collected soil and add it to 100 mL of sterilized water. Place it on a shaker and shake (180 revolutions per minute, shake for 30 min) to make a soil suspension. Then dilute the soil suspension by a factor of 10 in a gradient to 10 -4 times. Take 0.2 mL of the soil dilution and spread it on a solid medium without an organic carbon source. Incubate it at 28 °C for 7 days. The formula of the solid medium is: Na2HPO4 0.5 g / L, KH2PO4 0.5 g / L, MgSO4 0.3 g / L, CaCl2 0.2 g / L, NaHCO3 0.5 g / L, NH4Cl 0.5 g / L, NaNO3 0.25 g / L, NaCl 0.4 g / L, trace element solution 10 mL / L, agar 20 g / L; the pH value of the solid medium is 7.0. The formula of the trace element solution is: FeCl2 0.3 g / L, FeSO4·7H2O 0.3 g / L, MnSO4·H2O 0.15 g / L, ZnSO4·7H2O 0.25 g / L, CoCl2 0.2 g / L.

[0044] 2. Pick different colonies with better morphology, growth potential and faster growth rate on the solid medium without organic carbon source, and use the inoculation loop to streak plate and purify them on the new solid medium without organic carbon source for multiple times until pure culture. 25 carbon-fixing bacteria were initially isolated and purified by the dilution plate method. Select the dominant bacteria for the secondary screening of carbon-fixing function (refer to Example 2), and pick the one with the best effect as the research object, denoted as GD-1. Use a scanning electron microscope to determine that the cell morphology of this strain is short rod-shaped ( Figure 1 ), and the colonies produced on the solid medium are small, round, orange-red, opaque, with a smooth and viscous surface, neat edges and low convexity ( Figure 2 ).

[0045] 3. Further sequence the 16S rRNA gene of this strain: Use the universal primers 27F (SEQ ID NO.1) and 1492R (SEQ ID NO.2) to perform PCR amplification on the genomic DNA of the strain, and then sequence the amplification product. The sequencing result is shown in SEQ ID NO.3, as follows:

[0046] SEQ ID NO.1: 5'-AGTTTGATCMTGGCTCAG-3';

[0047] SEQ ID NO.2: 5'-GGTTACCTTGTTACGACTT-3';

[0048]

[0049] Then, using the NCBI database, BLAST analysis was performed based on the 16S rRNA gene sequence of the strain, and a phylogenetic tree was constructed ( Figure 3 ). The results showed that the 16S rRNA gene sequence of the strain was homologous to the genus Dietzia sp. (100% homology with Dietzia natronolimnaea strain DSM 44860 and Dietzia cercidiphyllistrain X0053). As Figure 3 can be seen, the isolated strain had the closest genetic evolutionary distance to the two. Combining its cell morphology and colony characteristics, the strain was identified as Dietzia sp. Further, whole-genome sequencing was performed on it: the extracted whole genome was sent to Shanghai Personal Biotechnology Co., Ltd. for second-generation sequencing, and the obtained sequence results were subjected to average nucleotide identity (ANI) analysis with the whole-genome sequence of the reference strain Dietzia natronolimnaea S-XJ-1 in the NCBI database. When the ANI value was greater than 95%, the two could be considered the same bacterial species. The ANI result showed 98.30%, so the strain was identified as Dietzia natronolimnaea. The strain GD-1 was deposited in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, and the deposit number was CGMCC No. 31728.

[0050] Example 2 Carbon fixation enzyme activity of the carbon-fixing bacterium Dietzia natronolimnaea GD-1

[0051] 1. Materials and methods

[0052] 1.1 Test strain: Dietzia natronolimnaea GD-1, isolated and identified in Example 1.

[0053] 1.2 Detection of RubisCO carbon fixation enzyme activity of Dietzia natronolimnaea GD-1

[0054] Pick the purified GD-1 colony in Example 1 and inoculate it into 10 mL of liquid medium without organic carbon source (same as in Example 1), and culture it at 28 °C and 160 r / min for 5 days. Take the bacterial liquid at the end of the culture for RubisCO enzyme activity determination. Use the ribulose bisphosphate carboxylase / oxygenase (RuBisCO) kit provided by Beijing Bioss Biotechnology Co., Ltd. for determination. At the same time, use the BCA protein concentration determination kit to measure the total protein content of the bacterial liquid, and standardize the RubisCO enzyme activity determination results. The specific measurement method refers to the kit instructions. The measurement results are shown in Figure 4, where Dietziasp. is Dietzia alkaliphila GD-1, and 1-4 are the other 4 carbon-fixing bacteria isolated and purified in Example 1.

[0055] 1.3 Data processing

[0056] The original data of this experiment was preliminarily sorted out using Microsoft Excel Office 2016 software. The experimental results were plotted using Graphpad Prism 9.5. The results are shown in Figure 4 , where different lowercase letters indicate significant differences between different groups.

[0057] 2. Results and analysis

[0058] From the results, the RuBisCO enzyme activity of Dietzia alkaliphila GD-1 is about 41.35 U / mg·prot, which is much greater than that of the other 4 carbon-fixing bacteria, indicating that it has good carbon-fixing ability.

[0059] Example 3 Study on the carbon-fixing ability of Dietzia alkaliphila GD-1 under different conditions

[0060] 1. Materials and methods

[0061] 1.1 Test strains: Dietzia alkaliphila GD-1, isolated and identified in Example 1.

[0062] Carbon-free liquid medium: Na2HPO4 0.5 g / L, KH2PO4 0.5 g / L, MgSO4 0.3 g / L, CaCl2 0.2 g / L, NH4Cl 0.5 g / L, NaNO3 0.25 g / L, NaCl 0.4 g / L, trace element solution 10 mL / L; pH value is 7.0. The formula of the trace element solution is: FeCl2 0.3 g / L, FeSO4·7H2O 0.3 g / L, MnSO4·H2O 0.15 g / L, ZnSO4·7H2O 0.25 g / L, CoCl2 0.2 g / L.

[0063] Na2CO3 liquid medium: Add Na2CO3 0.63 g / L on the basis of the carbon-free liquid medium, and the pH value is 7.0.

[0064] NaHCO3 liquid medium: Add NaHCO3 0.5 g / L on the basis of the carbon-free liquid medium, and the pH value is 7.0.

[0065] NaNO2 Liquid Medium: 4.6 g / L of NaNO2, 0.5 g / L of Na2HPO4, 0.5 g / L of KH2PO4, 0.3 g / L of MgSO4, 0.2 g / L of CaCl2, 0.5 g / L of NaHCO3, 0.5 g / L of NH4Cl, 0.25 g / L of NaNO3, 0.4 g / L of NaCl; pH value is 7.0.

[0066] Na2S2O3 Liquid Medium: Replace 4.6 g / L of NaNO2 in the NaNO2 liquid medium with 5 g / L of Na2S2O3, and the pH value is 7.0.

[0067] 1.2 Study on the Carbon Fixation Ability of Dietzia alkalilacus GD-1 under Different Inorganic Carbon Sources and Different Electron Donors

[0068] Pick the purified GD-1 colonies in Example 1 and inoculate them into 5 mL of carbon-free liquid medium, and culture at 28 °C, 160 r / min for 5 days. Take 1 mL of the bacterial liquid at the end of the culture. After measuring the strain abundance using a flow cytometer, take 400 μL and inoculate it into 5 mL of carbon-free liquid medium (denoted as Carbon-free), Na2CO3 liquid medium, NaHCO3 liquid medium, NaNO2 liquid medium, and Na2S2O3 liquid medium respectively, and make 3 parallels. After culturing at 28 °C for 5 days, detect the strain abundance in the bacterial liquid again. The specific measurement method of microbial abundance is as follows: Dilute SYBR-Green (10000×, Solarbio) 100 times, and mix it with propidium iodide (PI, Solarbio) at a ratio of 50:1 (the volume ratio of SYBR-Green and PI is 50:1) to obtain a fluorescent dye. After removing large particle impurities from 1 mL of the bacterial liquid through a 300-mesh nylon sieve, add 10 μL of the fluorescent dye and stain it in the dark for 15 minutes. After vortexing, detect it to determine the number of viable bacteria.

[0069] 1.3 Data Processing

[0070] The data of this experiment was analyzed in CytExpert SRT software and then preliminarily sorted using Microsoft Excel Office 2016 software. The experimental results were plotted using Graphpad Prism 9.5.

[0071] 2. Results and Analysis

[0072] Since during the strain culture process, the available carbon sources are only atmospheric carbon dioxide and inorganic carbon sources in the medium, the increase in strain biomass comes from carbon fixation by the strain. The experimental results of the carbon fixation ability of Dietzia alkalilacus GD-1 under different conditions are shown in Figure 5。The results showed that in the presence of only atmospheric carbon dioxide, the strain concentration of Dietzia natronolimnaea GD-1 in the alkaline lake could increase by 5,406.06 Events / μL per day, indicating its good ability to fix atmospheric carbon dioxide. When an external inorganic carbon source was added, the daily average growth rate of its strains increased slightly, indicating an improvement in its carbon fixation ability, which might be the result of the strain fixing carbon through other pathways. There was little difference in its utilization of the two different forms of inorganic carbon sources, and its daily average growth rates were 5,901.42 and 5,934.41 Events / μL respectively under the addition of NaHCO3 and Na2CO3. When an external electron donor was added, the carbon fixation ability of the strain was further enhanced. Compared with the addition of Na2S2O3 with a daily average growth rate of 6,085.67 Events / μL, when NaNO2 was added, the daily average growth rate could be significantly increased to 6,990.65 Events / μL, indicating that NaNO2 had a better effect on improving the carbon fixation ability of the strain, probably because NaNO2 could provide more energy for the strain to fix carbon. The results showed that Dietzia natronolimnaea GD-1 could maintain a good growth rate and carbon fixation ability in a very low-nutrient salt medium, and the related abilities could be driven by an electron donor. At the same time, it had a higher carbon fixation potential in a soil environment with a higher carbonate content, which was helpful for developing the application of the strain in special environments (such as karst soil).

[0073] Example 4 Analysis of the Carbon Fixation Pathway of the Carbon-Fixing Bacterium Dietzia natronolimnaea GD-1

[0074] 1. Materials and Methods

[0075] The Dietzia natronolimnaea GD-1 isolated and identified in Example 1 was sent to Shanghai Personal Biotechnology Co., Ltd. for second-generation sequencing using the Illumina Novaseq platform. A whole-genome framework map was assembled and spliced, and bioinformatics software and databases were used to annotate and functionally identify the bacteria. The carbon fixation pathway of strain GD-1 was speculated through the KEGG database to provide a basis for studying the carbon fixation ability of the strain. The results are shown in Figure 6 , where the letters represent the key enzymes in the carbon fixation pathway, pps - phosphoenolpyruvate carboxylase; ppc - phosphoenolpyruvate carboxylase; pycA - pyruvate carboxylase; maeB - malic enzyme; mdh - malate dehydrogenase; Fum - fumarate esterase; sdh / frd - succinate dehydrogenase; sucD - succinyl-CoA synthetase; korA - 2-oxoglutarate ferredoxin oxidoreductase; icd - isocitrate dehydrogenase; ACO - heptenoate hydratase; gltA - citrate synthase.

[0076] 2. Results and Analysis

[0077] Based on the KEGG database, the CO2 fixation pathway of Dietzia natronolimnaea GD-1 was determined. First, pyruvate forms phosphoenolpyruvate under the action of phosphoenolpyruvate synthase and fixes CO2 in the presence of phosphoenolpyruvate carboxylase to generate oxaloacetate. Oxaloacetate can be converted to malate under the catalysis of malate dehydrogenase. Malate can, on the one hand, be directly converted to pyruvate under the catalysis of malic enzyme to complete the carbon fixation cycle. On the other hand, it can form fumarate ester under the action of fumarate esterase and be converted to succinate by succinate dehydrogenase, and further form succinyl-CoA, and can fix two more molecules of CO2 during the formation of isocitrate. Subsequently, it forms citrate via cis-aconitate under the catalysis of heptenoate hydratase and finally converts to oxaloacetate to form the carbon fixation cycle( Figure 6 ). At the same time, the results of whole-genome analysis also found that Dietzia natronolimnaea GD-1 also has other key carbon fixation enzymes, such as 2-oxoglutarate:ferredoxin oxidoreductase, which further enhances the carbon fixation ability.

[0078] Example 5 Study on the phosphate-solubilizing ability of the carbon-fixing bacterium Dietzia natronolimnaea GD-1

[0079] 1. Materials and methods

[0080] 1.1 Test strains: Dietzia natronolimnaea GD-1, isolated and identified in Example 1.

[0081] Pikovskaya liquid medium: yeast extract 0.5 g / L, glucose 10 g / L, Ca3(PO4)2 5 g / L, (NH4)2SO4 0.5 g / L, KCl 0.2 g / L, Mg3(PO4)2 0.1 g / L, MgSO4 0.0001 g / L, FeSO4 0.0001 g / L; pH value is 7.0.

[0082] 1.2 Detection of the phosphate-solubilizing ability of the carbon-fixing bacterium Dietzia natronolimnaea GD-1

[0083] Dilute the 5 g / L KH2PO4 standard solution to concentrations of 0, 2, 2.5, 250, 500, 1000 mg / L, measure the absorbance using the molybdenum antimony anti-colorimetric method, and the standard curve equation obtained by measurement is y = 0.0028x + 0.048, R 2 = 0.9996.

[0084] The colonies purified from the solid medium without organic carbon source in Example 1 were inoculated into 10 mL of Pikovskaya liquid medium and cultured at 28 °C and 160 r / min for 5 days. A control group without inoculating the strain was set up. At the end of the culture, the bacterial liquid was centrifuged, 1 mL of sterile water was added to the cell pellet, ground using a tissue disruptor, mixed with the supernatant, and NaHCO3 was added followed by shaking and filtering. The organic phosphorus content was determined by the molybdenum antimony anti-colorimetric method. The measurement results are shown in Figure 7 , where Dietziasp. is Dietzia alkaliphila GD-1, and 1-4 are the other 4 carbon-fixing bacteria isolated and purified in Example 1.

[0085] 1.3 Data processing

[0086] The experimental data in this experiment were preliminarily sorted out using Microsoft Excel Office 2016 software. The experimental results were plotted using Graphpad Prism 9.5.

[0087] 2. Results and analysis

[0088] By taking the ability to dissolve tricalcium phosphate as an index, it was determined that Dietzia alkaliphila GD-1 has the ability to dissolve phosphorus, realizing the utilization of insoluble phosphate. Its phosphorus dissolution ability is 426.61 mg / L, while the phosphorus dissolution abilities of the other 4 carbon-fixing bacteria are as low as 115.18 mg / L at the lowest and only 301.25 mg / L at the highest, all lower than that of Dietzia alkaliphila GD-1.

[0089] In summary, the isolated Dietzia alkaliphila GD-1 of the present invention has the ability to fix atmospheric carbon dioxide, and at the same time it has the ability to dissolve phosphorus, providing strain resources for improving the carbon sequestration and emission reduction ability of saline-alkali soil, providing technical support for in-depth understanding of the microbial regulation process of the occurrence form of nutrients in saline-alkali soil, laying a foundation for proposing soil microbial improvement technologies in photovoltaic fields, and promoting the high-quality development of the photovoltaic industry in saline-alkali vulnerable areas.

[0090] Although the above embodiments have made a detailed description of the present invention, they are only a part of the embodiments of the present invention, not all embodiments. People can also obtain other embodiments based on these embodiments without creative work, and these embodiments all belong to the protection scope of the present invention.

Claims

1. A Dietzia natronolimnaea strain ( Dietzia natronolimnaea ) GD-1, with a preservation number of CGMCC No. 31728.

2. A carbon-fixing bacterial agent, characterized in that, including Dietzia natronolimnaea GD-1 as described in claim 1.

3. The carbon-fixing microbial inoculum according to claim 2, characterized in that, The OD of Dietzia alkaliphila GD-1 in the carbon fixation bacterial agent 600 value ≥ 0.

6.

4. The preparation method of the carbon-fixing bacterial agent according to claim 2 or 3, characterized in that, comprising the following steps: Inoculating Dietzia natronolimnaea GD-1 as described in claim 1 into a culture medium for cultivation to obtain the carbon-fixing microbial agent; the culture medium is a culture medium containing a carbon source or a culture medium without a carbon source.

5. The preparation method according to claim 4, characterized in that, The culture medium further includes an electron donor; the electron donor includes sodium nitrite and / or sodium thiosulfate.

6. The preparation method according to claim 4, characterized in that, The culture medium without a carbon source includes components with the following concentrations: 0.5 g / L of Na2HPO4, 0.5 g / L of KH2PO4, 0.3 g / L of MgSO4, 0.2 g / L of CaCl2, 0.5 g / L of NH4Cl, 0.25 g / L of NaNO3, 0.4 g / L of NaCl, 10 mL / L of trace element solution; the trace element solution includes components with the following concentrations: 0.3 g / L of FeCl2, 0.3 g / L of FeSO4·7H2O, 0.15 g / L of MnSO4·H2O, 0.25 g / L of ZnSO4·7H2O, 0.2 g / L of CoCl2; the pH value of the culture medium without a carbon source is 7.0-7.

4.

7. The preparation method according to claim 4, characterized in that, The culture medium containing a carbon source is prepared by adding a carbon source to the culture medium without a carbon source; the added carbon source includes: sodium carbonate and / or sodium bicarbonate.

8. Use of Dietzia natronolimnaea GD-1 as described in claim 1 or the carbon-fixing microbial agent as described in claim 2 or 3 in carbon fixation and / or dissolution of insoluble inorganic phosphorus, wherein the carbon source for carbon fixation includes an inorganic carbon source.

9. The application according to claim 8, characterized in that, The inorganic carbon source includes one or more of carbon dioxide, sodium bicarbonate, and sodium carbonate.

10. The application according to claim 8, wherein The insoluble inorganic phosphorus includes calcium phosphate.

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