Novel paenibacillus GD-2 and application thereof in carbon sequestration

Abstract

The invention relates to the technical field of microbial carbon sequestration, in particular to novel paenibacillus GD-2 and application thereof in carbon sequestration. The preservation number of the paenibacillus GD-2 disclosed by the invention is CGMCC (China General Microbiological Culture Collection Center) No. 31835. The paenibacillus GD-2 provided by the invention is a potential new strain in paenibacillus separated from fixed inter-plate soil in a salinization photovoltaic field area, has dual carbon sequestration capability, can convert carbon dioxide in the atmosphere into carbonate minerals, can grow by converting the carbon dioxide into own biochar (organic carbon), and has the advantages of being simple in preparation process and low in cost. The strain can grow under the condition that only atmospheric carbon dioxide is contained, meanwhile, the growth rate of the strain can be remarkably improved through NaHCO3, an external carbon source and an electron donor are not needed, the carbon sequestration cost is reduced, and the strain has important significance for improving the soil carbon sequestration and sink increasing potential, promoting high-quality development of the photovoltaic industry in a salinization fragile area and relieving global climate warming.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial carbon fixation, and in particular to a novel strain of Paenibacillus GD-2 and application thereof in carbon fixation. Background Art

[0002] Existing studies have shown that functional microorganisms such as nitrogen-fixing bacteria and cellulose-degrading bacteria play an important role in improving saline-alkali land, restoring soil physical and chemical properties and ecological environment. Improving soil carbon sequestration and carbon sink potential is an urgent need to restore the ecological function of saline-alkali land and mitigate climate change, but there is still a lack of research on the isolation and screening of soil carbon-fixing microorganisms and their carbon fixation capabilities, and there is even less research on the precise identification and screening of soil carbon-fixing microorganisms in saline-alkali photovoltaic fields. Therefore, isolating and screening highly efficient carbon-fixing indigenous functional microorganisms in saline-alkali photovoltaic fields has important potential application value in stimulating and enhancing the synergistic benefits of indigenous microorganisms in improving soil and fixing carbon and increasing carbon sinks. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a new type of Bacillus GD-2 and its application in carbon fixation. The Bacillus GD-2 provided by the present invention has dual carbon fixation ability, which can convert carbon dioxide in the atmosphere into carbonate minerals, and grow by converting carbon dioxide into its own biocarbon (organic carbon), which is of great significance for improving the potential of soil carbon fixation and sink, promoting the high-quality development of the photovoltaic industry in salinization-vulnerable areas, and alleviating global warming.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The invention provides a Paenibacillus sp. GD-2, whose deposit number is CGMCC No.31835.

[0006] The present invention provides a carbon-fixing microbial agent, comprising the Paenibacillus sp. GD-2 described in the above technical solution.

[0007] Preferably, the OD of Paenibacillus GD-2 in the carbon-fixing microbial agent is 600 Value ≥ 0.6.

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

[0009] The Paenibacillus sp. GD-2 described in the above technical solution is inoculated into a culture medium for cultivation to obtain the carbon-fixing microbial agent; the culture medium includes a culture medium that does not contain an organic carbon source.

[0010] Preferably, the culture medium without an organic carbon source comprises 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, and trace element solution 10 mL / L; the trace element solution comprises 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, and CoCl2 0.2 g / L; the pH value of the culture medium without an organic carbon source is 7.0 to 7.4.

[0011] Preferably, the culture medium not containing an organic carbon source further comprises an inorganic carbon source; the inorganic carbon source comprises sodium bicarbonate and / or sodium carbonate.

[0012] Preferably, the culture time is 5 to 7 days; and the culture temperature is 28°C.

[0013] The present invention provides the use of the Bacillus GD-2 described in the above technical scheme or the carbon-fixing microbial agent described in the above technical scheme or the carbon-fixing microbial agent prepared by the preparation method described in the above technical scheme in carbon fixation, and the carbon source for carbon fixation includes an inorganic carbon source.

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

[0015] Preferably, the carbon fixation includes: inducing an inorganic carbon source to generate carbon-containing minerals and / or utilizing the inorganic carbon source to convert into its own biochar.

[0016] Beneficial effects:

[0017] The present invention provides a strain of Paenibacillus GD-2, with a deposit number of CGMCC No. 31835. The Paenibacillus GD-2 provided by the present invention is a potential new species of the genus Paenibacillus isolated from the soil between fixed panels in a salinized photovoltaic field, has dual carbon fixation capabilities, can convert carbon dioxide in the atmosphere into carbonate minerals, and use carbon dioxide to convert into its own biocarbon (organic carbon) for growth, can grow under conditions containing only atmospheric carbon dioxide, and can use NaHCO3 to significantly increase its growth rate, does not require an external carbon source and electron donor, reduces the cost of carbon fixation, and is of great significance for improving the soil carbon fixation and sink potential, promoting the high-quality development of the photovoltaic industry in salinized vulnerable areas, and alleviating global warming. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 1 This is the bacterial morphology of Paenibacillus GD-2;

[0020] Figure 2 is the colony characteristic diagram of Paenibacillus GD-2;

[0021] Figure 3 is the phylogenetic tree of the 16S rRNA gene of Paenibacillus GD-2;

[0022] Figure 4 The results of RubisCO enzyme activity assay of Paenibacillus sp. GD-2;

[0023] Figure 5 The results of the determination of carbon fixation capacity of Paenibacillus GD-2 under different conditions;

[0024] Figure 6 The carbon fixation pathway of Paenibacillus sp. GD-2; the letters represent the key enzymes in the carbon fixation pathway, pps—phosphoenolpyruvate carboxylase; ppc—phosphoenolpyruvate carboxylase; aspC—aspartate aminotransferase; ItaE—threonine aldolase; glyA—glycine hydroxymethyltransferase; SDS—serine dehydrogenase;

[0025] Figure 7 This is the electron microscope scanning and element distribution map of the carbon-containing minerals induced by Paenibacillus GD-2 in urea broth medium;

[0026] Among them, * means p < 0.05, *** means p < 0.001, and **** means p < 0.0001.

[0027] Biological Deposit Description

[0028] Paenibacillus GD-2, classified and named Paenibacillus sp., was deposited in the General Microbiology Center (CGMCC) of China Microorganism Culture Collection on September 3, 2024. The deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 31835. DETAILED DESCRIPTION

[0029] The invention provides a strain of Paenibacillus GD-2, whose deposit number is CGMCC No.31835.

[0030] The Bacillus GD-2 provided by the present invention is a potential new species of the genus Bacillus isolated from the soil between fixed plates in a salinized photovoltaic field. The single colony is round, light yellow and viscous, with a moist, smooth, opaque and regular edge. It has dual carbon fixation capabilities, and can convert carbon dioxide in the atmosphere or inorganic carbon in the culture medium into carbonate minerals (including but not limited to calcium carbonate and isomorphs of calcium carbonate), as well as grow by converting carbon dioxide into its own biocarbon (organic carbon). It can grow under conditions containing only atmospheric carbon dioxide, and can significantly increase its growth rate by using NaHCO3. It does not require an external carbon source and electron donor, thereby reducing the cost of carbon fixation. It provides strain resources for improving the carbon fixation and emission reduction capacity of salinized soils, provides technical support for in-depth understanding of the microbial regulation process of the occurrence form of nutrients in salinized soils, lays the foundation for proposing soil microbial improvement technology in photovoltaic fields, and promotes the high-quality development of the photovoltaic industry in salinized vulnerable areas.

[0031] Based on the above advantages, the present invention provides a carbon-fixing microbial agent, including the Bacillus GD-2 described in the above technical solution.

[0032] As an embodiment, the OD of Bacillus sp. GD-2 in the carbon-fixing microbial agent is 600 Value ≥ 0.6.

[0033] The present invention provides a method for preparing the carbon-fixing microbial agent described in the above technical solution, comprising the following steps:

[0034] The Paenibacillus sp. GD-2 described in the above technical solution is inoculated into a culture medium for cultivation to obtain the carbon-fixing microbial agent; the culture medium includes a culture medium that does not contain an organic carbon source.

[0035] As an embodiment, the culture medium without organic 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, and 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, and CoCl2 0.2 g / L; the pH value of the culture medium without organic carbon source is 7.0-7.4.

[0036] As an embodiment, the culture medium without an organic carbon source also includes an inorganic carbon source; the inorganic carbon source includes sodium bicarbonate and / or sodium carbonate. By adding an inorganic carbon source, especially sodium bicarbonate, the growth rate of Paenibacillus sp. GD-2 can be significantly increased, thereby improving its carbon fixation capacity.

[0037] As one embodiment, the concentration of the inorganic carbon source in the culture medium without an organic carbon source is 0.3 to 0.8 g / L. As another embodiment, the concentration of the inorganic carbon source in the culture medium without an organic carbon source is 0.5 to 0.63 g / L.

[0038] As an embodiment, the culture time is 5 to 7 days; the culture temperature is 28°C.

[0039] Based on the above advantages, the present invention provides the use of the Bacillus GD-2 described in the above technical solution or the carbon-fixing microbial agent described in the above technical solution or the carbon-fixing microbial agent prepared by the preparation method described in the above technical solution in carbon fixation, and the carbon source for carbon fixation includes an inorganic carbon source. As an embodiment, the inorganic carbon source includes one or more of carbon dioxide, sodium bicarbonate and sodium carbonate. As another embodiment, the carbon dioxide is carbon dioxide in the atmosphere. The Bacillus GD-2 provided by the present invention can convert carbon dioxide in the atmosphere or inorganic carbon in the culture medium into carbonate minerals, and grow by converting carbon dioxide into its own biochar (organic carbon), thereby playing a dual carbon fixation role; the carbon-containing minerals include but are not limited to calcium carbonate and allomorphs of calcium carbonate.

[0040] In order to further illustrate the present invention, a novel strain of Bacillus GD-2 provided by the present invention and its application in carbon fixation are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1 Isolation and identification of carbon-fixing strain Paenibacillus GD-2

[0042] The target soil is the soil between fixed panels in the salinized photovoltaic field in Daqing. The specific screening scheme is as follows:

[0043] 1. Collect soil from a depth of 0 to 20 cm, take 10.0 g of the collected soil, add it to 100 mL of sterilized water, and place it on a shaker for shaking (180 rpm, shaking for 30 min) to make a soil suspension. Then dilute the soil suspension in a 10-fold gradient to 10 -4times, take 0.2mL of soil dilution, apply it to a solid culture medium without an organic carbon source, and culture it at 28°C for 7 days. The formula of the solid culture medium without an organic carbon source 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 10mL / L and agar 20 g / L, with a pH value of 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 and CoCl2 0.2 g / L.

[0044] 2. Pick different colonies with better morphology, better growth potential and faster growth rate from the solid culture medium without organic carbon source, and purify them multiple times on a new solid culture medium without organic carbon source by inoculation loop plate streak method until pure culture. Preliminary separation and purification of 25 strains of carbon-fixing bacteria were carried out by dilution plate method, and colonies with good growth potential were selected for carbon fixation function rescreening (refer to Example 2), and the one with the best effect was selected and recorded as GD-2. Scanning electron microscopy was used to determine that the bacterial morphology of the strain was rod-shaped ( Figure 1 ), the colonies produced on solid culture medium are small, round, light yellow and viscous, with a moist and smooth surface, opaque, and regular edges ( Figure 2 ).

[0045] 3. The strain was further subjected to 16S rRNA gene sequencing: the genomic DNA of the strain was amplified by PCR using universal primers 27F (SEQ ID NO.1) and 1492R (SEQ ID NO.2), and the amplified product was sequenced. The sequencing result is shown in SEQ ID NO.3, which is as follows:

[0046]

[0047] The primer sequences are as follows:

[0048] 27F (SEQ ID NO. 1): 5'-AGTTTGATCMTGGCTCAG-3';

[0049] 1492R (SEQ ID NO. 2): 5'-GGTTACCTTGTTACGACTT-3'.

[0050] Then, BLAST analysis was performed based on the strain 16S rRNA gene sequence using the NCBI database. The results showed that the strain had a homology of 99.79% with the 16S rRNA gene sequence of Paenibacillus pabulistrain Plu29 (accession number MK737158.1), 99.57% with the 16S rRNA gene sequence of Paenibacillus amylolyticus S124 (accession number AY509232.1), 99.29% with the 16S rRNA gene sequence of Paenibacillus vandeheii (accession number OQ836669.1) and Paenibacillus taichungensis Rz1.2-8 (accession number MN098861.1), and 99.08% with the 16S rRNA gene sequence of Paenibacillus xylanivorans A59 (accession number KT461879.1). Figure 3 As shown, 16S rRNA gene phylogenetic analysis showed that the strain had the closest phylogenetic relationship with Paenibacillus pabuli. Combined with its bacterial morphology and colony characteristics, the strain was identified as Paenibacillus sp.

[0051] However, the accurate classification of the strain cannot be determined only by 16S rRNA gene sequencing analysis. Further, the whole genome sequencing was performed on it: the extracted whole genome was sent to Shanghai Paisono Biotechnology Co., Ltd. for second-generation sequencing, and the obtained sequence results were compared with the whole genome sequences of the closely related species reference strains Paenibacillus pabuli NBRC13638, Paenibacillus amylolyticus SQR-21, Paenibacillus vandeheii F6_3S_P_1C, Paenibacillus taichungensis 53B and PaenibacillusxylanivoransA59 in the NCBI database for average nucleotide identity (ANI) analysis. When the ANI value is greater than 95%, the two can be considered to be the same species. The ANI results were 81.91%, 90.13%, 82.16%, 82.16% and 82.12%, respectively, indicating that the strain is different from the above-mentioned closest species and is a potential new species. The GD-2 strain was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration with the deposit number CGMCC No.31835.

[0052] Example 2 Carbon-fixing enzyme activity of carbon-fixing bacterium Paenibacillus GD-2

[0053] To determine the carbon fixation capacity of Paenibacillus GD-2, the Paenibacillus GD-2 colonies purified in Example 1 were selected and inoculated into 10 mL of liquid culture medium without an organic carbon source (same as in Example 1), and cultured at 28°C and 160 r / min for 5 days. 5 The RubisCO enzyme activity was determined by using the ribulose diphosphate carboxylase / oxygenase (RuBisCO) kit provided by Beijing Bioson Biotechnology Co., Ltd. At the same time, the total protein content of the bacterial liquid was measured using the BCA protein concentration determination kit to standardize the RuBisCO enzyme activity determination results. The specific measurement method refers to the kit instructions.

[0054] The raw data of this example was preliminarily sorted using Microsoft Excel Office 2016 software. The experimental results were plotted using GraphpadPism 9.5. The measurement results are shown in Figure 4 , wherein GD-2 is the Bacillus sp. GD-2 preserved in the present invention, and 1 to 4 are the other 4 carbon-fixing bacteria separated and purified in Example 1.

[0055] Depend on Figure 4It can be seen that the RuBisCO enzyme activity of Bacillus GD-2 is about 19.6U / mgprot, which is much greater than that of the other four carbon-fixing bacteria, indicating that it has good carbon fixation ability.

[0056] Example 3 Study on the carbon fixation ability of carbon-fixing bacterium Paenibacillus GD-2 under different conditions

[0057] The culture medium formula used in this example is as follows:

[0058] Carbon-free liquid culture 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 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.

[0059] Na2CO3 liquid culture medium: Add Na2CO30.63 g / L to the carbon-free liquid culture medium, and the pH value is 7.0.

[0060] NaHCO3 liquid culture medium: Add NaHCO3 0.5 g / L to the carbon-free liquid culture medium, and the pH value is 7.0.

[0061] NaNO2 liquid culture medium: NaNO24.6 g / L, Na2HPO40.5 g / L, KH2PO40.5 g / L, MgSO40.3 g / L, CaCl20.2 g / L, NaHCO30.5 g / L, NH4Cl 0.5g / L, NaNO30.25 g / L, NaCl 0.4g / L, pH value is 7.0.

[0062] Na2S2O3 liquid culture medium: Replace NaNO24.6 g / L in NaNO2 liquid culture medium with Na2S2O35 g / L, and the pH value is 7.0.

[0063] Study on the carbon fixation ability of Paenibacillus sp. GD-2 under different inorganic carbon sources and different electron donors

[0064] The Bacillus GD-2 colony purified in Example 1 was selected and inoculated into 5 mL of carbon-free liquid culture medium, and cultured at 28°C, 160 r / min, for 5 days. 5CFU / mL) 1mL, after the strain abundance was determined by flow cytometry, 400μL was inoculated into 5mL carbon-free liquid medium (recorded as CO2), Na2CO3 liquid medium, NaHCO3 liquid medium, NaNO2 liquid medium and Na2S2O3 liquid medium, and three parallels were set up. After culturing at 28℃ for 5 days, the strain abundance in the bacterial liquid was detected again. The specific measurement method of microbial abundance is as follows: SYBR-Green (10000×, Solebol) was diluted 100 times and mixed with propidium iodide (PI, Solebol) at a volume ratio of 50:1 (SYBR-Green:PI) to obtain fluorescent dye. After 1mL of bacterial liquid was passed through a 300-mesh nylon sieve to remove large particles, 10μL of fluorescent dye was added to stain in the dark for 15 minutes, and the number of viable bacteria was determined after vortexing.

[0065] The data of this example were analyzed in CytExpert SRT software and then preliminarily sorted using Microsoft Excel Office 2016 software. The experimental results were plotted using Graphpad Pism 9.5. Figure 5 .

[0066] Since the only carbon sources available to the strain during the cultivation process are atmospheric carbon dioxide and inorganic carbon sources in the culture medium, the increase in the strain biomass comes from carbon fixation by the strain. The results show that in the case of atmospheric carbon dioxide alone, the strain concentration of Paenibacillus GD-2 can increase by 331.79 Events / μL per day, indicating that it has a certain fixation capacity for atmospheric carbon dioxide. When an inorganic carbon source is added, the average daily growth rate of the strain increases, especially when NaHCO3 is added, its carbon fixation capacity is significantly improved (nearly ten times), and the average daily growth rate of the strain can reach 3232.25 Events / μL, which may be the result of carbon fixation by other pathways. When an electron donor is added, the carbon fixation capacity of the strain is not improved, but will be weakened to varying degrees. When Na2S2O3 is added, its average daily growth rate is 851.09 Events / μL, and when NaNO2 is added, the growth of the strain cannot even be detected.

[0067] The above results indicate that Paenibacillus GD-2 can grow in extremely low-nutrient salt culture media without relying on electron donors, and has a higher carbon fixation potential in soil environments with high carbonate and bicarbonate content, which helps to develop the application of strains in special environments (such as soda saline-alkali land).

[0068] Example 4 Analysis of Carbon Fixation Pathway of Paenibacillus GD-2

[0069] 1. Materials and methods

[0070] The Bacillus GD-2 isolated and identified in Example 1 was sent to Shanghai Paisonno Biotechnology Co., Ltd. for second-generation sequencing using the Illumina Novasek platform, and the whole genome framework map was assembled and spliced. The bacteria were annotated and functionally identified using bioinformatics software and databases, and the carbon fixation pathway of strain GD-2 was inferred through the KEGG database to provide a basis for studying the carbon fixation ability of the strain.

[0071] 2. Results and Analysis

[0072] Based on the KEGG database, the CO2 fixation pathway of strain GD-2 was clarified. First, CO2 is fixed by phosphoenolpyruvate to generate oxaloacetate, which is then converted into L-aspartate by aspartate aminotransferase, and then converted into threonine. Threonine is cleaved into glycine by threonine aldolase, and glycine is then converted into serine by glycine hydroxymethyltransferase, and finally converted into pyruvate by serine dehydrogenase to form a carbon fixation cycle ( Figure 6 ). The first stable product produced when this pathway fixes CO2 is the four-carbon compound oxaloacetate, which is then converted into phosphoenolpyruvate through the conversion of various amino acids. The synthesis and degradation of threonine are the core processes in this cycle. In addition, biological carbon fixation is usually completed under the catalysis of a series of enzymes. Strain GD-2 can also achieve the conversion of acetyl-CoA with HCO3 under the catalysis of acetyl-CoA carboxylase (ACC), an enzyme with high carbon fixation efficiency. - The reaction produces malonyl-CoA, which is the first step in the synthesis of fatty acids and other substances. This also explains to a certain extent that the addition of inorganic carbon source NaHCO3 significantly improves the carbon fixation capacity of this strain.

[0073] Example 5 Study on the induction of carbon-containing minerals by carbon-fixing bacteria Paenibacillus sp. GD-2

[0074] 1. Materials and methods

[0075] 1.1 Test strain: Paenibacillus GD-2, isolated and identified in Example 1.

[0076] Urea broth liquid culture medium: peptone 1.0 g / L, glucose 1.0 g / L, NaCl 5.0 g / L, Na2HPO4 1.2 g / L, KH2PO4 0.8 g / L, phenol red 0.004 g / L; pH 7.0.

[0077] 1.2 Detection and analysis of carbon-containing minerals produced by carbon-fixing bacterium Paenibacillus GD-2

[0078] The Bacillus GD-2 colony purified in Example 1 was inoculated into 10 mL of urea broth liquid culture medium and cultured at 28° C., 160 r / min for 5 days. A control group without inoculation of the strain was set up. At the end of the culture, 1 mL of the bacterial solution was added with 1 mL of 350 mmol / L CaCl2·2H2O solution. After being placed on a shaker for 15 min and centrifuged at a speed of 16179 g for 5 min, the precipitate was placed in a 50° C. oven for drying for 24 h and weighed. The precipitate was further subjected to electron microscopy scanning and energy dispersive diffraction analysis to explore the morphology, structure and elemental composition information of the precipitate.

[0079] 2. Results and Analysis

[0080] After the culture was completed, a total of 8.9 mg of precipitate was obtained, and scanning electron microscopy showed that ( Figure 7 ) The sediment has a flaky structure and a porous structure where microorganisms live. According to energy dispersion diffraction analysis, the main components of the sediment are carbon, oxygen, and calcium, and the atomic percentage is close to 1:3:1 ( Figure 7 and Table 1), it was judged that the precipitate was calcium carbonate, indicating that the Bacillus GD-2 had the ability to generate carbon-containing minerals and could convert carbon dioxide in the atmosphere or inorganic carbon in the culture medium into carbonate minerals through metabolic processes to achieve carbon fixation (mineralization and carbon fixation).

[0081] Table 1 Elemental composition of precipitate

[0082] Element Type Atomic percentage (%) carbon 13.29 oxygen 65.38 calcium 21.33 total 100

[0083] In summary, the Bacillus GD-2 screened by the present invention has a dual carbon fixation ability of fixing inorganic carbon into organic carbon or inorganic carbon, that is, it can convert carbon dioxide in the atmosphere or inorganic carbon in the culture medium into carbonate minerals, and can also use carbon dioxide or inorganic carbon in the culture medium to convert into its own biocarbon (organic carbon) for growth, providing bacterial resources for improving the carbon fixation and emission reduction capacity of salinized soils, providing technical support for in-depth understanding of the microbial regulation process of the storage form of nutrients in salinized soils, laying the foundation for proposing soil microbial improvement technology in photovoltaic areas, and promoting the high-quality development of the photovoltaic industry in salinized vulnerable areas.

[0084] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A strain of Paenibacillus sp. GD-2, with a deposit number of CGMCC No. 31835.

2. A carbon-fixing microbial agent, characterized in that: It comprises the Paenibacillus GD-2 described in claim 1.

3. The carbon-fixing microbial agent according to claim 2, characterized in that: The OD of Paenibacillus GD-2 in the carbon-fixing microbial agent 600 Value ≥ 0.

6.

4. The method for preparing the carbon-fixing microbial agent according to claim 2 or 3, characterized in that: The following steps are involved: The Paenibacillus sp. GD-2 described in claim 1 is inoculated into a culture medium for cultivation to obtain the carbon-fixing microbial agent; the culture medium includes a culture medium that does not contain an organic carbon source.

5. The preparation method according to claim 4, characterized in that: The culture medium without organic carbon source comprises 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, and trace element solution 10 mL / L; the trace element solution comprises 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, and CoCl2 0.2 g / L; the pH value of the culture medium without organic carbon source is 7.0-7.

4.

6. The preparation method according to claim 4 or 5, characterized in that: The culture medium not containing an organic carbon source also includes an inorganic carbon source; the inorganic carbon source includes sodium bicarbonate and / or sodium carbonate.

7. The preparation method according to claim 4, characterized in that: The culture time is 5 to 7 days; the culture temperature is 28°C.

8. Use of the Bacillus GD-2 described in claim 1, the carbon-fixing microbial agent described in claim 2 or 3, or the carbon-fixing microbial agent prepared by the preparation method described in any one of claims 4 to 7 in carbon fixation, wherein the carbon source for carbon fixation includes an inorganic carbon source.

9. The use 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 use according to claim 8 or 9, characterized in that: The carbon fixation includes: inducing an inorganic carbon source to generate carbon-containing minerals and / or utilizing the inorganic carbon source to convert into its own biocarbon.

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