Algae inhibiting and sterilizing method

Abstract

The method comprises the following steps: adding diacetyl into a water body to be treated, playing a role under the irradiation of sunlight, and inhibiting the growth of algae and fungi; the algae are skeletonema costatum, phaeocystis globosa, microcystis aeruginosa or prorocentrum donghaiense; the fungus is escherichia coli or staphylococcus aureus. According to the method, diacetyl is adopted as an active substance, the algal inhibition and sterilization effects can be achieved only under natural light, and the method is good in selectivity, environmentally friendly, economical, efficient and suitable for algal control and disinfection of shallow lakes, swimming pools, seawater / freshwater farms and landscape water bodies.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, and particularly relates to a method for inhibiting algae and killing bacteria. Background Art

[0002] With the rapid improvement of industrialization and urbanization, a large amount of industrial wastewater and domestic sewage is discharged into rivers, lakes, reservoirs and oceans, causing the accumulation of substances such as carbon, nitrogen and phosphorus and eutrophication of water bodies, resulting in the massive reproduction of harmful algae in the water bodies, which not only has a negative impact on the aquatic ecosystem, but also threatens the safety of human drinking water and causes serious economic losses to agriculture, fisheries, etc.

[0003] At present, the methods for removing harmful algae and bacteria mainly include physical methods, chemical methods and biological methods. Among them, the physical method is mainly through mechanical salvage, heating or ultraviolet sterilization. Although these methods are fast-acting, they have high operating costs and rely on specific equipment, making it difficult to achieve large-scale application; the biological method mainly relies on the filter feeding or allelopathic effect of aquatic plants and animals, which is slow to take effect and has poor controllability; the chemical method achieves the inhibition and killing of harmful algae and bacteria by adding chemical agents. It has the advantages of simple operation and quick effect, and is the preferred method for emergency algae control and antibacterial. However, most chemical algaecides have poor selectivity and high ecological risks, which limits their application in natural water bodies and functional water bodies. Therefore, the development of new algaecidal and antibacterial methods is of great significance to improving water quality and maintaining the stability of the ecosystem. Summary of the invention

[0004] Purpose of the invention: The present invention aims to provide an ecologically safe algae-inhibiting and sterilization method.

[0005] Technical solution: The algae-inhibiting and bactericidal method of the present invention is to add diacetyl into the water to be treated, and to exert its effect under the irradiation of sunlight to inhibit the growth of algae and fungi.

[0006] The chemical formula of the diacetyl is CH3COCOCH3, and the structural formula is

[0007] Preferably, the algae is Skeletonema costatum, Phaeocystis sphericalensis, Microcystis aeruginosa or Prorocentrum donghaiense.

[0008] Preferably, the fungus is Escherichia coli or Staphylococcus aureus.

[0009] Preferably, when inhibiting algae, the concentration of diacetyl in the water to be treated is not less than 0.2 mM. The algae inhibition effect increases with the increase of diacetyl concentration.

[0010] Preferably, the algae density range is 4.4×10 5 ~1.1×10 7With the increase of algae density, the anti-algae effect of diacetyl at the same concentration first increased and then slightly weakened.

[0011] Preferably, when the algae is Skeletonema costatum, the concentration of diacetyl in the water to be treated is 0.2-0.6 mM.

[0012] Preferably, when the algae is Phaeocystis sphericalensis or Microcystis aeruginosa, the concentration of diacetyl in the water to be treated is 0.2-0.6 mM.

[0013] Preferably, when the algae is Prorocentrum donghaiense, the concentration of diacetyl in the water to be treated is 0.4-0.6 mM.

[0014] Preferably, when inhibiting bacteria, the concentration of diacetyl in the water to be treated is not less than 0.1 mM, and the antibacterial effect increases with the increase of diacetyl concentration.

[0015] Preferably, the mushroom density range is 3.6×10 3 ~1.0×10 8 CFU / mL, with the increase of colony density, the treatment time of diacetyl at the same concentration gradually prolonged.

[0016] The water body to be treated is a shallow lake, a swimming pool, a seawater / freshwater farm or a landscape water body.

[0017] Invention mechanism: In the present invention, diacetyl can inhibit algae and kill bacteria. The mechanism is that diacetyl photolyzes under sunlight to produce acetyl peroxyl radicals, which cause algae or bacterial cells to produce oxidative stress and die. In the present invention, diacetyl selectively inhibits Microcystis aeruginosa, Phaeocystis sphericalensis, Prorocentrum donghaiense or Skeletonema midrib, and has no effect on the growth of Chlamydomonas reinhardtii under the same conditions.

[0018] Diacetyl has the advantages of being environmentally friendly and economically efficient. Environmentally friendly: Diacetyl is a common natural substance that is widely found in plants (lavender, tulips, strawberries, etc.) and fermented products such as wine and yogurt. It is also a metabolite of microorganisms and the human body, and has good biocompatibility and environmental friendliness. Economically efficient: Compared with other natural substances that are difficult to extract, the industrial production conditions of diacetyl are mature, and it has the advantages of being easy to obtain and economically applicable.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The method uses diacetyl as the active substance, which can exert the effects of inhibiting algae and killing bacteria only under natural light, has good selectivity, is environmentally friendly, and is economical and efficient; (2) The method is simple to operate; (3) Diacetyl is stable and safe, easy to transport and operate, and does not require professional personnel to operate; (4) The method selectively has an inhibitory effect on Skeletonella, Phaeocystis spherica, Microcystis aeruginosa and Prorocentrum donghaiense, as well as Escherichia coli and Staphylococcus aureus. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The graphs of the inhibition of diacetyl on the algae density of Microcystis aeruginosa, Phaeocystis sphericalensis, Skeletonema midrib, and Prorocentrum donghaiense measured in Examples 1 to 4;

[0021] Figure 2 This is a graph showing the inhibition of the growth process of Chlamydomonas reinhardtii by diacetyl measured in Comparative Example 1;

[0022] Figure 3 This is a graph showing the inactivation effect of diacetyl on Microcystis aeruginosa at different initial densities as measured in Example 5;

[0023] Figure 4 This is a graph showing the inactivation effect of diacetyl on Escherichia coli measured in Example 6;

[0024] Figure 5 This is a graph showing the inactivation effect of diacetyl on Staphylococcus aureus measured in Example 7;

[0025] Figure 6 This is a comparison chart of the effects of diacetyl and other common algae-inhibiting and bactericidal substances measured in Comparative Example 2;

[0026] Figure 7 is the electron paramagnetic resonance (EPR) spectrum of diacetyl measured under light in Example 8;

[0027] Figure 8 This is a diagram showing the effect of diacetyl on treating harmful algae and bacteria in natural water bodies as measured in Examples 9 and 10. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with embodiments.

[0029] The diacetyl used in the examples of the present invention is analytically pure.

[0030] The algae described in the embodiments of the present invention are partially unicellular red tide algae isolated from the coast of East China: Phaeocystis spherical, Skeletonema midrib and Prorocentrum donghaiense, and freshwater algae from the Wuhan Freshwater Algae Seed Bank of the Chinese Academy of Sciences: Microcystis aeruginosa FACHB-905 and Chlamydomonas reinhardtii FACHB-265. The red tide algae are cultured in f / 2 medium, and the freshwater algae are cultured in BG11 medium.

[0031] The bacteria described in the embodiments of the present invention are Escherichia coli DH5α and Staphylococcus aureus ATCC25923, both of which are cultured in LB broth medium.

[0032] The term "water" in the present invention refers to ultrapure water unless otherwise specified or limited.

[0033] The main components of f / 2 culture medium are: NaNO3, 75mg / L; Na2SiO3·9H2O, 30mg / L; NaH2PO4·3H2O, 5mg / L; Na2EDTA·2H2O, 4.36mg / L; FeCl3·6H2O, 3.15mg / L; MnCl2·6H2O, 1.8mg / L; Vitamin B1, 0.1mg / L; ZnSO4·7H2O, 22ug / L; CoCl2·6H2O, 10ug / L; CuSO4·5H2O, 9.8ug / L; Na2MoO4·2H2O, 6.3ug / L; Biotin, 0.5ug / L; Vitamin B12, 0.5ug / L.

[0034] The main components of BG11 culture medium are: NaNO3, 1.5g / L; MgSO4·7H2O, 0.075g / L; CaCl2·2H2O, 0.036g / L; K2HPO4·3H2O, 0.04g / L; Na2CO3, 0.02g / L; citric acid, 6mg / L; ammonium ferric citrate, 6mg / L; Na2EDTA, 1mg / L; H3BO3, 2.86mg / L; MnCl2·4H2O, 1.86mg / L; ZnSO4·7H2O, 0.22mg / L; Na2MoO4·2H2O, 0.39mg / L; CuSO4·5H2O, 0.08mg / L; Co(NO3)2·6H2O, 0.05mg / L.

[0035] The main components of LB broth medium are: tryptone, 10 g / L; yeast extract, 5 g / L; NaCl, 10 g / L.

[0036] In the embodiment, the absorbance (OD) at 680 nm was measured by an ultraviolet spectrophotometer (UV-2700). 680 ) to evaluate the algae-inhibiting properties of diacetyl.

[0037] In the embodiment, a turbidity meter (2100P) can be used to measure turbidity, which proves the effectiveness of diacetyl in inhibiting algae in natural water bodies.

[0038] Example 1: The inhibitory effect of diacetyl on Phaeocystis sphericalensis

[0039] In a sterile clean bench, take the spherical Phaeocystis in the exponential growth phase and inoculate it into a sterile 50 mL quartz reaction bottle and a sterile six-well plate, and make its OD 680 The concentration of diacetyl in the reaction bottle was 0.22, and then different volumes of diacetyl dilution (100 mM) were added to the reaction bottle and the sterile six-well plate to make the final concentration of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group (CK) without diacetyl was set up; the quartz reaction bottle was sealed with a fully transparent film and placed in sunlight (50 mW / cm 2 ) were placed in the dark, and samples were taken at 0h, 2h, 4h, 6h, 8h, and 10h after the reaction to determine the OD 680 , and according to the formula Y = 99.148OD 680 –0.881Calculate the algal cell density (Y, 10 5 cells / mL).

[0040] Example 2: The inhibitory effect of diacetyl on Skeletonema midrib

[0041] Take the Skeletonium costatum in the exponential growth phase and inoculate it into a sterile 50 mL quartz reaction bottle and a sterile six-well plate to make the OD 680 The concentration of diacetyl in the reaction bottle was 0.14, and then different volumes of diacetyl dilution (100 mM) were added to the reaction bottle and the sterile six-well plate to make the final concentration of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group without diacetyl was set up; the quartz reaction bottle was sealed with a fully transparent film and placed in sunlight (50 mW / cm 2 ) were placed in the dark, and samples were taken at 0h, 2h, 4h, 6h, 8h, and 10h after the reaction to determine the OD 680 , and according to Y = 33.612OD 680 –0.546Calculate the algal cell density (Y, 10 5 cells / mL).

[0042] Example 3: The inhibitory effect of diacetyl on Prorocentrum donghaiense

[0043] Under sterile conditions, take the cells in the exponential growth phase and place them in sterile 50 mL quartz reaction bottles and sterile six-well plates until the OD 680The concentration of diacetyl in the reaction bottle was 0.14, and then different volumes of diacetyl dilution (100 mM) were added to the reaction bottle and the sterile six-well plate to make the final concentration of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group without diacetyl was set up; the quartz reaction bottle was sealed with a fully transparent film and placed in sunlight (50 mW / cm 2 ) were placed in the dark, and samples were taken at 0h, 2h, 4h, 6h, 8h, and 10h after the reaction to determine the OD 680 , and according to Y = 20.609OD 680 +0.091Calculate the algal cell density (Y, 10 5 cells / mL).

[0044] Example 4: Inhibitory effect of diacetyl on Microcystis aeruginosa

[0045] Microcystis aeruginosa FACHB-905 in the exponential growth phase was inoculated into a sterile 50 mL quartz reaction bottle and a sterile six-well plate, and the OD 680 The concentration of diacetyl in the reaction bottle was 0.20, and then different volumes of diacetyl dilution (100 mM) were added to the reaction bottle and the sterile six-well plate to make the final concentration of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group without diacetyl was set up; the quartz reaction bottle was sealed with a fully transparent film and placed in sunlight (50 mW / cm 2 ) were placed in the dark, and samples were taken at 0h, 2h, 4h, 6h, 8h, and 10h after the reaction to determine the OD 680 , and according to Y = 28.660OD 680 +0.078Calculate the algal cell density (Y, 10 6 cells / mL).

[0046] The test results of Examples 1 to 4 are as follows Figure 1 shown.

[0047] Figure 1 The following are the algae density diagrams of diacetyl inhibiting Phaeocystis sphericalensis (a), Skeletonema costatum (b), Prorocentrum donghaiense (c) and Microcystis aeruginosa (d) under light and dark conditions. Figure 1It can be seen that for spherical brown cysts, Prorocentrum donghaiense and Microcystis aeruginosa, the effect of diacetyl treatment for 2 hours under light was not obvious, and there was almost no effect on the growth of algal cells, but at this time, diacetyl showed a significant algae inhibition effect on the middle costal algae. With the increase of treatment time, diacetyl with a concentration greater than 0.2mM reduced the algae density of the four algae, and the algae inhibition effect increased with the increase of concentration, among which 0.6mM diacetyl had the best algae inhibition effect. 0.2mM diacetyl had almost no inhibitory effect on Prorocentrum donghaiense, but it could effectively inhibit the other three algae and showed a continuous growth inhibition effect within the treatment time range. Overall, the algae inhibition effect of diacetyl was: middle costal algae> spherical brown cysts, Microcystis aeruginosa> Prorocentrum donghaiense. Compared with the light conditions, the algae density of the four algae treated with different concentrations of diacetyl in the dark was not significantly different from that of the control group, indicating that diacetyl itself had no significant inhibitory effect on algal cells at the treatment concentration.

[0048] Comparative Example 1: Inhibitory Effect of Diacetyl on Chlamydomonas reinhardtii

[0049] Chlamydomonas reinhardtii FACHB-265 in the exponential growth phase was inoculated into a sterile 50 mL quartz reaction bottle and a sterile six-well plate to a concentration of OD 680 The concentration of diacetyl in the reaction bottle was 0.20, and then different volumes of diacetyl dilution (100 mM) were added to the reaction bottle and the sterile six-well plate to make the final concentration of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group without diacetyl was set up; the quartz reaction bottle was sealed with a fully transparent film and placed in sunlight (50 mW / cm 2 ) were placed in the dark, and samples were taken at 0h, 2h, 4h, 6h, 8h, and 10h after the reaction to determine the OD 680 , and according to Y = 31.726OD 680 +0.087Calculate the algal cell density (Y, 10 5 cells / mL). Test results are as follows Figure 2 shown.

[0050] Figure 2 The figure is a graph showing the change in algae density of Chlamydomonas reinhardtii treated with diacetyl for 10 hours under light and dark conditions in Comparative Example 1. As shown in the figure, regardless of the presence or absence of sunlight, diacetyl treatment has no effect on the growth of Chlamydomonas reinhardtii, indicating that Chlamydomonas reinhardtii has a stronger tolerance to diacetyl than the other four algae, and diacetyl has the ability to selectively inhibit algae.

[0051] Example 5: Inactivation effect of diacetyl on Microcystis aeruginosa at different initial densities

[0052] Microcystis aeruginosa FACHB-905 in the exponential growth phase was inoculated into a sterile 50 mL quartz reaction bottle and a sterile six-well plate, and the OD 680The concentrations of diacetyl and acetyl were 0.1, 0.2, 0.3, and 0.4, respectively. Then, diacetyl dilution (100 mM) was added to the reaction bottle to make the final concentration of diacetyl 0.4 mM, and a blank control group without diacetyl was set up. The quartz reaction bottle was sealed with a transparent film and placed in sunlight (50 mW / cm 2 ) was sampled and measured at 0h, 2h, 4h, 6h, 8h, and 10h of reaction. 680 , and according to Y = 28.660OD 680 +0.078Calculate the algal cell density (Y, 10 6 cells / mL). Test results are as follows Figure 3 shown.

[0053] Figure 3 The figure shows the inhibitory effect of 0.4 mM diacetyl on different initial densities of Microcystis aeruginosa under sunlight. As can be seen from the figure, when the algae density of Microcystis aeruginosa is 3.1×10 6 -1.1×10 7 cells / mL range, diacetyl can achieve significant algae inhibition within 10 hours.

[0054] Example 6: The inactivation effect of diacetyl on Escherichia coli

[0055] Escherichia coli DH5α was selected for inactivation experiment. Take the Escherichia coli solution that has reached the logarithmic growth phase at 37°C and 200rpm, centrifuge at 5000rpm for 5min, discard the supernatant, and collect the precipitate. Resuspend the bacterial precipitate in sterile saline (0.9% NaCl, pH 7.0) and centrifuge again. Repeat the above steps three times to completely remove the culture medium residue. Finally, resuspend in sterile saline to obtain a pure bacterial suspension and dilute to 1.0×10 7 CFU / mL.

[0056] The bacterial suspension was added to a quartz reaction tube, and different volumes of diacetyl were added to make the final concentration of diacetyl 0.01mM, 0.1mM, 0.2mM, 0.3mM, and a blank control was set. The quartz reaction bottle was sealed with a transparent film and placed under sunlight (50mW / cm 2 ), during the treatment process, the reaction suspension was taken at regular intervals, appropriately diluted, and 0.1 mL of the diluted sample was evenly spread on an LB agar medium plate, and the number of colonies formed on the plate was counted after incubation at 37°C for 24 h.

[0057] 0.2 mM diacetyl was further selected to determine its killing effect on E. coli at different concentrations.

[0058] Resuspend E. coli according to the above method and dilute to 1.0×106 -1.0×10 8 CFU / mL. Take the bacterial solution and add it to the quartz reaction tube, add 0.2mM diacetyl, and set up a blank control. Use the coating method to count the colonies. The test results are as follows Figure 4 shown.

[0059] Figure 4 This is a diagram showing the inactivation effect of diacetyl on Escherichia coli. Figure 4 As shown in (a), when the concentration of diacetyl is not less than 0.1 mM, it exhibits excellent bactericidal effect, and as the concentration of diacetyl increases, the bactericidal effect is also enhanced. Figure 4 (b) It can be seen that 0.2 mM diacetyl has a significant effect on the colony density of 1.0×10 6 -1.0×10 8 It has a good inactivation effect on Escherichia coli with a CFU / mL and can be completely inactivated within 75 minutes.

[0060] Example 7: Inactivation effect of diacetyl on Staphylococcus aureus

[0061] Select Staphylococcus aureus ATCC25923 under the same culture conditions as Escherichia coli for inactivation experiment. Collect the bacterial suspension in the logarithmic growth phase and centrifuge (5000rpm, 5min), discard the supernatant, and collect the precipitate. Resuspend the bacterial precipitate in sterile saline (0.9% NaCl, pH 7.0) and centrifuge again. Repeat this step three times to completely remove the culture medium residue. Finally, resuspend in sterile saline to obtain a pure bacterial suspension. The colony count is 1.0×10 7 CFU / mL of Staphylococcus aureus was added to a quartz reaction tube, and 0.2mM diacetyl was added. The experiment was carried out under sunlight and dark conditions, and a blank control was set. The test results are as follows Figure 5 shown.

[0062] Figure 5 The inactivation effect of diacetyl on Staphylococcus aureus. Figure 5 As shown, in addition to Escherichia coli (Gram-negative bacteria), diacetyl also has a significant inactivation effect on Staphylococcus aureus (Gram-positive bacteria), and can completely inactivate Staphylococcus aureus after 120 minutes of exposure to sunlight.

[0063] Comparative Example 2: Comparison of the inhibitory effects of diacetyl and other common algae-inhibiting and fungicidal substances on Microcystis aeruginosa

[0064] Based on the above experimental results, we further selected Microcystis aeruginosa as a representative species for comparative experiments. Microcystis aeruginosa FACHB-905 in the exponential growth phase was inoculated into a sterile 50 mL quartz reaction bottle and its OD 680The concentration of diacetyl, hydrogen peroxide, peracetic acid, persulfate and periodate was 0.4 mM. A blank control group without any algae inhibitor was set up. The quartz reaction bottle was sealed with a transparent film and placed in sunlight (50 mW / cm 2 ) was sampled and measured at 0h, 2h, 4h, 6h, 8h, and 10h of reaction. 680 , and according to Y = 28.660OD 680 +0.078Calculate the algal cell density (Y, 10 6 cells / mL). Test results are as follows Figure 6 shown.

[0065] Figure 6 This is a comparison chart of the inhibitory effects of diacetyl and other common algaecides on Microcystis aeruginosa. As can be seen from the figure, strong oxidants such as hydrogen peroxide and peracetic acid showed good algae inhibition effects in the early stage. Diacetyl, periodate, and persulfate took effect slowly, but as the experiment progressed, diacetyl showed obvious algae inhibition effects in the later stage, and the final algae inhibition effect after 10 hours of treatment was better than peracetic acid and hydrogen peroxide.

[0066] Example 8: Electron paramagnetic resonance (EPR) spectrum of diacetyl under light

[0067] First, ultrapure water is placed in an oxygen-free glove box to prepare oxygen-free water, a certain volume of diacetyl solution is prepared, and then 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) is added as a capture agent, mixed and slowly added to a capillary quartz tube, and sealed with vaseline. The capillary is placed in the cavity of the EPR instrument, and in-situ illumination is performed at a distance of about 1m from the sample. The EPR signal of the sample at 0min and 5min is measured. The test results are as follows: Figure 7 shown.

[0068] Figure 7 This is the EPR spectrum of diacetyl under light. As shown in the figure, the EPR spectrum obtained in an anaerobic environment shows six main peaks from the DMPO-CH3C(O)· adduct. In addition, a weaker peak belonging to DMPO-CH3· was also detected. Under aerobic conditions, CH3C(O)· can quickly combine with oxygen molecules to generate oxidative acetyl peroxyl radicals.

[0069] Example 9: Effect of diacetyl on the treatment of Microcystis aeruginosa in natural water

[0070] Take 30L of water from Tianlai River (32°7′8″N, 118°56′67″E) and add Microcystis aeruginosa FACHB-905 (OD 680=0.6) 500mL and cultured to the exponential growth phase, then added an appropriate volume of diacetyl and mixed well, so that the concentration of the treatment group was 0.5mM, and a blank control group without diacetyl was set up. Samples were taken at regular intervals every day from the 0th day to the 8th day, and the anti-algae effect of diacetyl in natural water was determined by turbidity measurement. The test results are shown in Figure 7 shown.

[0071] Depend on Figure 8 (a) It can be seen that the Microcystis aeruginosa in the control group grew vigorously, and the turbidity rose to 35NTU on the third day and remained at around 25NTU in the next few days. However, the turbidity of the experimental group treated with diacetyl dropped to below 10NTU within one day and remained at a relatively low level during the subsequent observation period.

[0072] Example 10: Effect of diacetyl on bacteria in natural water

[0073] Take 20L of water from Tianlai River (32°7′8″N, 118°56′67″E), filter it with gauze, remove impurities and plant residues, place it in a polypropylene transparent water tank, place it under sunlight, and add 0.2mM diacetyl. Take samples regularly at 0, 2, 4, 6, 8, and 12 hours, and dilute them appropriately. Spread 0.1mL of the diluted sample evenly on the plate, and count the number of colonies formed on the plate after incubation at 37°C for 18 hours. The test results are as follows: Figure 8 (b) as shown.

[0074] like Figure 8 As shown in (b), the addition of diacetyl can quickly inactivate bacteria in water within 6 h, which has the potential for practical application.

Claims

1. A method for inhibiting algae and killing bacteria, characterized in that: Diacetyl is added to the water to be treated and works under sunlight to inhibit the growth of algae and fungi.

2. The method for inhibiting algae and killing bacteria according to claim 1, characterized in that: The algae are Skeletonema costatum, Phaeocystis sphericalensis, Microcystis aeruginosa or Prorocentrum donghaiense.

3. The method for inhibiting algae and killing bacteria according to claim 1, characterized in that: The fungi are Escherichia coli or Staphylococcus aureus.

4. The method for inhibiting algae and killing bacteria according to claim 2, characterized in that: The concentration of diacetyl in the water to be treated is not less than 0.2 mM.

5. The method for inhibiting algae and killing bacteria according to claim 3, characterized in that: The concentration of diacetyl in the water to be treated is not less than 0.1 mM.

6. The method for inhibiting algae and killing bacteria according to claim 2, characterized in that: The algae density range is 4.4×10 5 ~1.1×10 7 cells / mL.

7. The method for inhibiting algae and killing bacteria according to claim 6, characterized in that: When the algae is Skeletonema costatum, the concentration of diacetyl in the water to be treated is 0.2-0.6 mM.

8. The method for inhibiting algae and killing bacteria according to claim 6, characterized in that: When the algae is Phaeocystis sphericalensis or Microcystis aeruginosa, the concentration of diacetyl in the water to be treated is 0.2-0.6 mM.

9. The method for inhibiting algae and killing bacteria according to claim 6, characterized in that: When the algae is Prorocentrum donghaiense, the concentration of diacetyl in the water to be treated is 0.4-0.6 mM.

10. The method for inhibiting algae and killing bacteria according to claim 3, characterized in that: The fungus density range is 3.6×10 3 ~1.0×10 8 CFU / mL.

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