A method for improving the carbon fixation efficiency of Navicula biopump

Abstract

The present invention discloses a method for improving the carbon fixation efficiency of the Navicula biological pump, belonging to the field of Navicula application technology. The method comprises the following steps: culturing Navicula in a growth environment supplemented with sodium selenite, wherein the concentration of the added sodium selenite in the Navicula growth environment does not exceed 1.0 ppm. This method can increase the siliceous skeleton (i.e., the shell) of the Navicula under selenium stress, thereby increasing the silicon content, siliceous skeleton stability, and sedimentation rate of individual diatoms, thereby improving the carbon fixation efficiency of the biological pump.

Description

Technical Field

[0001] The present invention relates to the technical field of Navicula application, and in particular to a method for improving the carbon fixation efficiency of a Navicula biological pump. Background Art

[0002] Navicula is an important diatom in coastal zones and one of the most widely distributed marine diatoms in the world. Its efficient photosynthetic capacity makes it important for marine carbon sequestration. However, although Navicula fixes atmospheric carbon dioxide and carries this carbon into the sedimentary layer through its siliceous skeleton after its death, its siliceous skeleton (the Navicula shell) is relatively small and therefore settles slowly in seawater, making it prone to dissolution in pore water and other media. This results in a low carbon sequestration efficiency of the Navicula biological pump (which stores atmospheric carbon dioxide on the seafloor).

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The object of the present invention is to provide a method for improving the carbon fixation efficiency of the Navicula biopump to solve the above technical problems.

[0005] This application can be implemented as follows:

[0006] In a first aspect, the present application provides a method for improving the carbon fixation efficiency of the Navicula biopump, comprising the following steps:

[0007] Navicula is cultured in a growth environment supplemented with sodium selenite, wherein the concentration of the added sodium selenite in the growth environment does not exceed 1.0 ppm.

[0008] In an optional embodiment, the concentration of the added sodium selenite in the growth environment is 0.1-1.0 ppm.

[0009] In an optional embodiment, the growth environment is a seawater environment.

[0010] In an alternative embodiment, the seawater comprises natural seawater or artificial seawater.

[0011] In an alternative embodiment, the source of sodium selenite is pharmaceutical wastewater.

[0012] In an optional embodiment, f / 2 culture medium is further added to the growth environment.

[0013] In an alternative embodiment, the culture temperature is 5-30°C.

[0014] In a preferred embodiment, the culture temperature is 25°C.

[0015] In an optional embodiment, during the culture process, the light and dark cycle is 6-12h / 6-12h.

[0016] In an optional embodiment, during the culture process, the corresponding light intensity under bright conditions is 50-150 μEm -2 ·s -1 .

[0017] In a preferred embodiment, the corresponding light intensity under bright conditions is 100 μEm -2 ·s -1 .

[0018] The beneficial effects of this application include:

[0019] The method provided in this application can increase the siliceous skeleton of Navicula (i.e., the shell of Navicula) (i.e., increase the aspect ratio) under the stress of a specific concentration of selenium, which is beneficial to increase its carbon content and sedimentation rate, thereby improving its biological pump carbon fixation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 These are field emission scanning electron micrographs of the Navicula skeleton under selenium stress (1.0 ppm) and without selenium stress in the experimental examples of this application. DETAILED DESCRIPTION

[0022] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0023] The method for improving the carbon fixation efficiency of the Navicula biopump provided in this application is described in detail below.

[0024] The inventors proposed that increasing the size of Navicula and its siliceous skeleton (Navicularia shell) can increase the organic matter content. After the diatom dies, the organic matter can sink rapidly under the "ballast" effect of the siliceous skeleton. This is a feasible way to increase the carbon content, reduce the solubility of the skeleton, and improve the efficiency of the diatom biological pump.

[0025] In order to increase the size of the siliceous skeleton of Navicula (Navicularia shell), the inventors conducted extensive research and creatively discovered that selenium at a specific concentration can make the Navicula skeleton "grow", that is, the aspect ratio increases, which is beneficial to increase the sedimentation rate and carbon fixation capacity.

[0026] Based on this, the present application proposes a method for improving the carbon fixation efficiency of the Navicula biopump, comprising the following steps:

[0027] Navicula is cultured in a growth environment supplemented with sodium selenite, wherein the concentration of the added sodium selenite in the growth environment does not exceed 1.0 ppm.

[0028] For reference, the concentration of added sodium selenite in the growth environment of Navicula can be 0.1ppm, 0.2ppm, 0.3ppm, 0.4ppm, 0.5ppm, 0.6ppm, 0.7ppm, 0.8ppm, 0.9ppm, 1.0ppm, etc., or any other value not exceeding 1.0ppm.

[0029] In some preferred embodiments, the concentration of added sodium selenite in the growth environment is 0.1-1.0 ppm.

[0030] By controlling the amount of selenium added within the above range, the siliceous skeleton (shell) of Navicula can be enlarged under selenium stress, specifically increasing the original aspect ratio of approximately 1.5:1 to >2.5:1. When the added concentration of sodium selenite exceeds 15 ppm, the growth of Navicula can be inhibited.

[0031] When the siliceous skeleton of Navicula increases to >2.5:1, its corresponding sedimentation velocity can increase by about 300% compared with the original sedimentation velocity, and its carbon fixation capacity can be increased by more than 200%.

[0032] In the present application, the growth environment of Navicula is a seawater environment.

[0033] In an alternative embodiment, the seawater comprises natural seawater or artificial seawater.

[0034] When artificial seawater is used, it can prevent other organisms from interfering with the growth of Navicula, such as cyanobacteria from competing with it.

[0035] Alternatively, the source of the sodium selenite may be selenium-containing wastewater, such as pharmaceutical wastewater containing sodium selenite.

[0036] Furthermore, the method provided by the present application also includes: adding f / 2 culture medium to the growth environment of Navicula.

[0037] The f / 2 culture medium contains sodium nitrate, disodium hydrogen phosphate, vitamins, trace elements, sodium silicate, and the like.

[0038] It should be noted that the f / 2 culture medium used in this application is a conventional algae culture medium in the art. The specific dosage of its components and the preparation method can refer to the existing technology and will not be described in detail here.

[0039] By adding f / 2 culture solution, the rapid growth of Navicula can be promoted. The specific amount of f / 2 culture solution added can be set according to needs.

[0040] In the present application, the culture temperature of Navicula can be 5-30°C, such as 5°C, 8°C, 10°C, 15°C, 20°C, 22°C, 25°C, 28°C or 30°C, or any other value within the range of 5-30°C.

[0041] In some preferred embodiments, the culture temperature of Navicula is 25° C., which is more suitable for its growth.

[0042] During the culture process, the light and dark cycle can be set to 6-12h / 6-12h, preferably 12h / 12h. That is, culture under light conditions for 12h, then culture under dark conditions for 12h, and so on.

[0043] The corresponding light intensity under the above-mentioned bright conditions can be 50-150 μEm -2 ·s -1 , such as 50μEm -2 ·s -1 、60μEm -2 ·s -1 、70μEm -2 ·s -1 、80μEm -2 ·s -1 、85μEm -2 ·s -1 、90μEm -2 ·s -1 、95μEm -2 ·s -1 、100μEm -2 ·s -1 、105μEm -2 ·s -1 、110μEm -2 ·s -1 、115μEm -2 ·s -1 、120μEm -2 ·s -1 、130μEm -2 ·s -1 、140μEm -2 ·s -1 or 150 μEm -2 ·s -1etc., can also be 50-150μEm -2 ·s -1 Any other value within the range.

[0044] In a preferred embodiment, the corresponding light intensity under bright conditions is 100 μEm -2 ·s -1 This condition is easier to achieve and control, and the lighting conditions are more suitable for the growth of Navicula.

[0045] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0046] Example 1

[0047] This embodiment provides a method for improving the carbon fixation efficiency of the Navicula biopump, comprising the following steps:

[0048] The pharmaceutical wastewater containing sodium selenite to be treated is introduced into natural seawater added with f / 2 culture medium, and Navicula is added for culture.

[0049] In the above process, the concentration of sodium selenite added in natural seawater is 0.1 ppm.

[0050] The culture temperature of Navicula was 25°C, the light-dark cycle was 12h / 12h, and the light intensity under the bright condition was 100μEm -2 ·s -1 The size of Navicula increased by 111.5% in length and 22.1% in width.

[0051] Example 2

[0052] The difference between this embodiment and embodiment 1 is that:

[0053] The concentration of added sodium selenite in natural seawater is 0.5 ppm.

[0054] The culture temperature of Navicula was 20°C, the light-dark cycle was 12h / 12h, and the light intensity under the light condition was 80μEm -2 ·s -1 The size of Navicula increased by 133.3% in length and 27.5% in width.

[0055] Example 3

[0056] The difference between this embodiment and embodiment 1 is that:

[0057] The concentration of added sodium selenite in natural seawater is 1.0 ppm.

[0058] The culture temperature of Navicula was 30°C, the light-dark cycle was 12h / 12h, and the corresponding light intensity under light conditions was 120μEm-2 ·s -1 The size of Navicula increased by 243.3% in length and 58.3% in width.

[0059] Example 4

[0060] The difference between this embodiment and embodiment 1 is that the seawater is artificial seawater prepared according to the composition of natural seawater. The size of the Navicula increased by 119.3% in length and 25.5% in width.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 1 is that the added selenium element is provided by a sodium selenate reagent. Navicula is difficult to grow.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that the pharmaceutical wastewater containing sodium selenite to be treated is directly introduced into the natural seawater where Navicula is growing, that is, no f / 2 culture medium is added. Navicula is difficult to grow.

[0065] Test example

[0066] 1.1 Experimental Materials

[0067] Navicula;

[0068] Sodium selenite (used to prepare Navicula culture medium with different concentration gradients) and sodium selenate reagent.

[0069] 1.2 Laboratory culture and transfer of Navicula

[0070] The culture conditions of Navicula were as follows: conventional culture was performed using f / 2 culture medium (containing sodium nitrate, disodium hydrogen phosphate, vitamins, trace elements, and sodium silicate), culture temperature was 25°C, light and dark cycle was 12h / 12h, and light intensity was 100μEm -2 s -1 .

[0071] The seed preservation and transfer procedure is as follows: 1.4L of artificial seawater (formula see table below) is placed in a 2L conical flask and sterilized at high temperature and high pressure in a vertical pressure steam autoclave for 30 minutes. After cooling, the flask is sterilized under UV light in a clean bench for 20 minutes. 1.5mL of 1000-fold concentrated f / 2 culture medium (sterilized) is added to the seawater to prepare 1.4L of f / 2 culture medium. 100mL of algal liquid is added to the culture medium. After shaking, the flask is placed in a constant temperature, light-treated incubator and cultured under the above conditions.

[0072] Table 1 Artificial seawater formula

[0073]

[0074] 1.3 Navicula cultivation experiment under sodium selenite-rich conditions

[0075] A 1000 mg / L stock solution was prepared using sodium selenite and purified water and sterilized. This stock solution was added to the culture medium of Navicula to obtain concentrations of 0.1, 0.5, and 1.0 ppm, respectively. Two parallel experiments were performed in each setting.

[0076] The following is the data analysis:

[0077] Figure 1 A and Figure 1 Figures (b) in the middle show FESEM images of Navicula before and after addition of 1.0 ppm sodium selenite. These images show that, without sodium selenite, individual Navicula cells measured approximately 5 × 7 μm. In a high-Se concentration environment, Navicula cells exhibited significant morphological changes, not only exhibiting a distinct depression in the central region but also, more significantly, increasing in overall length, resulting in an aspect ratio exceeding 2:1, significantly exceeding that of the blank sample (approximately 1.5:1). Specifically, the length increased by 243.3% and the width by 58.3%. This image demonstrates that Se stress can cause the Navicula cells to grow larger.

[0078] In summary, the method provided in this application can enlarge the siliceous skeleton of Navicula (i.e., the shell of Navicula) under the stress of selenium, thereby increasing the silicon content, siliceous skeleton stability and sedimentation rate of individual diatoms, and thus improving the carbon fixation efficiency of its biological pump.

[0079] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for improving the carbon fixation efficiency of Navicula biopump, characterized in that: The following steps are involved: Cultivating Navicula in a growth environment supplemented with sodium selenite, wherein the concentration of the added sodium selenite in the growth environment does not exceed 1.0 ppm; The growth environment is further added with f / 2 culture solution.

2. The method according to claim 1, characterized in that The concentration of the added sodium selenite in the growth environment is 0.1-1.0 ppm.

3. The method according to claim 1 or 2, characterized in that The growth environment is a seawater environment.

4. The method according to claim 3, characterized in that The seawater includes natural seawater or artificial seawater.

5. The method according to claim 1, characterized in that The source of the sodium selenite is pharmaceutical wastewater.

6. The method according to claim 1, characterized in that The culture temperature is 5-30℃.

7. The method according to claim 1, characterized in that During the culture process, the light-dark cycle was 6-12h / 6-12h.

8. The method according to claim 1, characterized in that During the culture process, the corresponding light intensity under bright conditions is 50-150µEm -2 ·s -1 .

9. The method according to claim 8, characterized in that The culture temperature was 25°C and the light intensity under bright conditions was 100µEm -2 ·s -1 .

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