A method for inhibiting algal growth based on ligand binding to algae

Abstract

The application discloses a method for inhibiting growth of algae based on ligand binding, and relates to the technical field of biological ligand binding. The method comprises the following steps: adding a ligand solution into water containing algae, and performing light irradiation. The algae comprises cyanobacteria. The cyanobacteria comprises Microcystis aeruginosa. The ligand comprises EDTA, NTA, DTPA and L-methionine. The concentration of the ligand solution is 0.05mmol / L ‑1 .

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biological ligand binding technology, and particularly relates to a method for inhibiting algal growth based on the property of ligand binding to Microcystis aeruginosa. BACKGROUND

[0002] Under the background of global climate change, the global warming, the increase of carbon dioxide concentration, the enhancement of ultraviolet radiation, and the increase of the probability of extreme weather caused by climate change make blue-green algae have more competitive advantage than other algae in the process of global climate change, resulting in the increase of the frequency of blue-green algae bloom and the outbreak of algal bloom, and the algal toxins produced thereby pose a serious threat to human and animal health. Blue-green algae is a kind of photoautotrophic prokaryotic algae, which is commonly found in various water environments around the world, and can easily overgrow under eutrophic water body and specific environmental conditions to form eutrophication. Microcystis aeruginosa is a kind of blue-green algae commonly found in freshwater, and its unique heteromorphous cell can fix atmospheric nitrogen into available nitrogen source for other nutrient cells. When it reproduces in large quantities in eutrophic water body, it can cause water quality deterioration, and in addition, Microcystis aeruginosa can release microcystin, which can cause secondary pollution to aquaculture water body, leading to poor development or death of farmed animals.

[0003] The traditional water treatment process has poor coagulation effect and removal effect when treating algae-containing water because the density of algal cells is small and the flocs formed during coagulation are loose. The methods for removing algae include chemical method, biological method and physical method. Blue-green algae is an autotrophic organism that can perform photosynthesis, and the photosynthesis of blue-green algae mainly depends on the energy conversion of photosystem reaction center I, photosystem II and phycobilisome. Oxidizing agents can destroy the energy and quality transmission in the process of algal photosynthesis. Chemical method mainly uses oxidizing agents such as H2O2, KMnO4, O3 and chlorides to inhibit the growth and photosynthesis of algal cells, so as to inactivate the algal cells and improve the removal rate of algae. Due to the strong motility and diverse morphology of Microcystis aeruginosa, it is difficult to be effectively removed. In addition to the characteristics of Microcystis aeruginosa, the production of algal organic matter is also an important factor. Algal organic matter includes extracellular and intracellular organic matter, which is mainly composed of polysaccharides, proteins and lipids. It is of practical significance and good application prospect to find a method for inhibiting the growth of Microcystis aeruginosa in aquaculture water body where Microcystis aeruginosa grows in large quantities. SUMMARY

[0004] In order to inhibit the growth of Microcystis aeruginosa in aquaculture water when the water bloom phenomenon occurs, prevent the large reproduction of Microcystis aeruginosa in aquaculture water to produce water bloom and hinder the growth of aquaculture animals, the purpose of the present application is to seek a method based on different ligand properties, which reacts with organic matter in the algae body to hinder the absorption of organic matter by Microcystis aeruginosa, thereby effectively inhibiting the growth of the algae body. The method is easy to control in preparation condition and simple in operation method.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a method for inhibiting the growth of algae based on ligand combination, comprising the following steps: adding a ligand solution into water containing algae, and performing light irradiation.

[0006] Preferably, the method for inhibiting the growth of algae based on ligand combination, the algae comprises cyanobacteria.

[0007] Preferably, the method for inhibiting the growth of algae based on ligand combination, the cyanobacteria comprises Microcystis aeruginosa.

[0008] Preferably, the method for inhibiting the growth of algae based on ligand combination, the ligand comprises EDTA, NTA, DTPA and L-methionine.

[0009] More preferably, the method for inhibiting the growth of algae based on ligand combination, the ligand is L-methionine.

[0010] Preferably, the method for inhibiting the growth of algae based on ligand combination, the concentration of the ligand solution is 0.05mmol·L -1 .

[0011] The present application has the following beneficial effects:

[0012] 1. The method provided by the present application is aimed at aquaculture water in which Microcystis aeruginosa grows in large quantities, and by selecting and adding a corresponding type of ligand, the ligand reacts with organic matter in the algae body to hinder the absorption of organic matter by Microcystis aeruginosa, thereby inhibiting the growth of Microcystis aeruginosa, which has practical significance and good application prospect.

[0013] 2. The method provided by the present application can inhibit the growth of Microcystis aeruginosa in aquaculture water when the water bloom phenomenon occurs, and prevent the large reproduction of Microcystis aeruginosa in aquaculture water to produce water bloom. The method is easy to control in preparation condition and simple in operation method. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the influence of different ligands on the growth amount of Microcystis aeruginosa algae in the method of the present application.

[0015] Figure 2Effect of different ligands on photosynthesis of Microcystis aeruginosa in the method of the present application.

[0016] Figure 3 Effect of different ligands on chlorophyll content of Microcystis aeruginosa in the method of the present application. DETAILED DESCRIPTION

[0017] The present application is further described below in conjunction with specific examples.

[0018] Example 1: A method for inhibiting growth of algal cells based on ligand binding

[0019] In this example, Microcystis aeruginosa is used as an example of algal cells. The Microcystis aeruginosa used in the experiment was obtained from the State Key Laboratory of Marine and Environmental Sciences, Xiamen University.

[0020] The method is as follows:

[0021] 1. Stock solutions of EDTA, NTA, DTPA and L-methionine with a concentration of 0.1 mmol·L -1 were prepared using distilled water and stored at 4°C in the dark. The stock solutions were filtered through a 0.45 μm microporous filter, and the filtered solutions were diluted with distilled water to prepare 0.05 mmol·L -1 aqueous ligand solutions for use in the experiment.

[0022] 2. The Microcystis aeruginosa was stored in MA basal medium (MA basal medium composition: Ca(NO3)2 50 mg·L -1 , KNO3 100 mg·L -1 , Na2SO4 40 mg·L -1 , NaNO3 50 mg·L -1 , MgCl2 50 mg·L -1 , FeCl3 0.5 mg·L -1 , MnCl2 5 mg·L -1 , ZnCl2 0.5 mg·L -1 , CoCl2 5 mg·L -1 , Na2MoO4 0.8 mg·L -1 , H3BO3 20 mg·L -1 , Na2PO4 100 mg·L -1 , Bicine 500 mg·L -1 ).

[0023] 3. The algal cells were expanded for about 1 week before the experiment, and the initial algal cell concentration was about 5.0 x 10 5 cell·mL -1 .

[0024] Algal cells in exponential growth phase were selected, and were filtered and transferred to new culture medium every 1-2 days. During the experiment, proper concentration of nutrients was added to ensure that the cells were adapted to the culture conditions.

[0025] Algal body culture stage: light intensity control is 3000lx; light-dark ratio control is 12h:12h; temperature control is 28℃; during the light period, artificial shaking is needed 2-3 times per day.

[0026] 4, respectively take 100mL MA basic culture based on 5 groups of 250mL conical flask, add 50mL Microcystis aeruginosa algal body culture solution respectively, add 10mL ligand aqueous solution (EDTA, NTA, DTPA and L-methionine) with a concentration of 0.05mmol·L -1 , one group does not add other ligands except adding 10mL distilled water, as a blank control group, and corresponding label is pasted, and algal body culture is carried out.

[0027] 5, the method for measuring algal body biomass by using a hemocytometer; the photosynthetic activity is determined by using a phytoplankton classification fluorescence instrument; the chlorophyll content is determined by using a phytoplankton classification fluorescence instrument, and the data obtained by the blank group are compared. The results are as Figures 1-3 .

[0028] Figure 1 The figure is the influence of different ligands on the biomass of Microcystis aeruginosa in the method of the application. Compared with the blank group, the culture solution added with NTA, DTPA and EDTA promotes the growth of Microcystis aeruginosa in a certain time range or maintains the growth with the blank group, and the promoting effect is enhanced in turn. The rest of the ligands, i.e. the culture solution added with L-methionine, inhibits the growth of Microcystis aeruginosa in the detection period, and the inhibition effect is obvious.

[0029] Figure 2 The figure is the influence of ligands on the photosynthetic activity of Microcystis aeruginosa in the method of the application. Compared with the blank group, the culture solution added with EDTA, NTA and DTPA promotes the photosynthetic activity of Microcystis aeruginosa in a certain time range or maintains the photosynthetic activity with the blank group. The rest of the ligands, i.e. the culture solution added with L-methionine, inhibits the photosynthetic activity of Microcystis aeruginosa in the detection period, and the inhibition effect is obvious.

[0030] Figure 3 The figure is the influence of ligands on the chlorophyll content of Microcystis aeruginosa in the method of the application. Compared with the blank group, the culture solution added with NTA, DTPA and EDTA promotes the growth of Microcystis aeruginosa in a certain time range or maintains the growth with the blank group, and the promoting effect is enhanced in turn. The rest of the ligands, i.e. the culture solution added with L-methionine, inhibits the growth of Microcystis aeruginosa in the detection period, and the inhibition effect is obvious.

[0031] In actual production, in some areas, the bait amount of artificial breeding species is too large, which leads to the increase of residual bait in the pool, increases the probability of water bloom phenomenon, and seriously pollutes the water quality of aquaculture. Therefore, according to the application, by adding an appropriate amount of L-methionine to the aquaculture water body, not only the growth and photosynthesis of Microcystis aeruginosa can be inhibited, but also the chlorophyll content of Microcystis aeruginosa can be inhibited. By adding L-methionine ligand, the number of Microcystis aeruginosa in the aquaculture water body can be quickly reduced, the occurrence of water bloom phenomenon in the aquaculture water body can be effectively prevented, and certain technical support and theoretical basis for controlling water bloom phenomenon in aquaculture industry are provided.

Claims

1. A method for inhibiting growth of algal cells based on ligand binding to algae, characterized by, It comprises the following steps: adding ligand solution into water body containing Microcystis aeruginosa, the concentration of the ligand solution is 0.05 mmol·L -1 , and carrying out light irradiation; the ligand comprises EDTA, NTA, DTPA and L-methionine.

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