Methods for suppressing and sterilizing algae

Abstract

To provide an ecologically safe method for controlling and sterilizing algae. [Solution] The present invention discloses a method for inhibiting and sterilizing algae, wherein diacetyl is added to the water to be treated and acts under sunlight irradiation to inhibit the growth of algae and fungi, the algae being Skeletonema costatum, synonyms, Microcystis erginosa, or red tide dinoflagellates, and the fungi being Escherichia coli or Staphylococcus aureus. The present invention uses diacetyl as the active substance, can exert algae-inhibiting and sterilizing effects under natural light alone, has good selectivity, is environmentally friendly, economical and efficient, and is applicable to algae-inhibiting and disinfection of shallow lakes, swimming pools, seawater / freshwater aquaculture farms, or landscape water bodies.

Description

[Technical Field]

[0001] This invention belongs to the field of water treatment, and more particularly to methods for suppressing and sterilizing algae. [Background technology]

[0002] With the rapid increase in industrialization and urbanization, large amounts of industrial and domestic wastewater are discharged into rivers, lakes, dams, and oceans, leading to the accumulation of substances such as carbon, nitrogen, and phosphorus, as well as eutrophication of the water bodies. This results in the massive proliferation of harmful algae and fungi in the water, not only negatively impacting aquatic ecosystems but also threatening the safety of drinking water for humanity and causing serious economic losses to agriculture, fisheries, and other sectors.

[0003] Currently, methods for removing harmful algae and fungi mainly include physical, chemical, and biological methods. Physical methods primarily involve mechanical removal, heating, or ultraviolet sterilization. While these methods are fast-acting, they have high operating costs, rely on specific equipment, and are difficult to implement on a large scale. Biological methods primarily rely on the filtering or allelopathic effects of aquatic plants and animals, resulting in slower effectiveness and poor controllability. Chemical methods, which involve administering chemical agents to suppress and sterilize harmful algae, offer advantages such as ease of operation and rapid effectiveness, making them the first-choice method for emergency algal and fungal control. However, many chemical algal and fungal inhibitors have poor selectivity, high ecological risks, and limit their application to natural and functional water bodies. Therefore, developing new algal suppression and sterilization methods is of crucial importance for improving water quality and maintaining ecosystem stability. [Overview of the project] [Problems that the invention aims to solve]

[0004] Objective of the invention: The present invention aims to provide an ecologically safe method for suppressing and sterilizing algae. [Means for solving the problem]

[0005] Technical solution: The method for suppressing algae and sterilization described in the present invention is to add diacetyl to the water body to be treated, act under sunlight irradiation, and suppress the growth of algae and fungi.

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

Chemical formula

[0007] Preferably, the algae are Skeletonema costatum, Synonym, Microcystis aeruginosa or red tide dinoflagellates.

[0008] Preferably, the fungi are Escherichia coli or Staphylococcus aureus.

[0009] Preferably, when suppressing algae, the concentration of the diacetyl in the water body to be treated is 0.2 mM. The algae suppression effect is enhanced with the increase of the diacetyl concentration.

[0010] Preferably, the algae density range is 4.4×10 5 ~1.1×10 7 cells / mL. With the increase of the algae density, the algae suppression effect of the diacetyl at the same concentration is first enhanced and then slightly weakened.

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

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

[0013] Preferably, when the algae are red tide dinoflagellates, the concentration of the diacetyl in the water body to be treated is 0.4 - 0.6 mM.

[0014] Preferably, when suppressing fungi, the concentration of diacetyl in the treated water is 0.1 mM or higher. The antimicrobial effect is enhanced as the diacetyl concentration increases.

[0015] Preferably, the fungal density range is 3.6 × 10 3 ~1.0×10 8 The concentration is CFU / mL, and as the colony density increases, the diacetyl treatment time at the same concentration gradually increases.

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

[0017] Mechanism of Invention: In this invention, diacetyl can exert algal inhibitory and bactericidal effects. The mechanism is that diacetyl photodegrades under sunlight irradiation to generate acetylperoxyl radicals, which cause oxidative stress in algal or fungal cells, leading to their death. In this invention, diacetyl selectively inhibits Microcystis erginosa, its synonym, red tide dinoflagellates, or Skeletonema costatum, while not affecting the growth of Euglena under similar conditions.

[0018] Diacetyl has the advantages of being environmentally friendly, economical, and efficient. Environmentally friendly: Diacetyl is a common natural substance, widely present in plants (lavender, tulips, strawberries, etc.) and fermented products such as alcoholic beverages and yogurt. It is also a metabolite of microorganisms and the human body, possessing good biocompatibility and being environmentally friendly. Economical and efficient: Compared to other natural substances that are difficult to extract, the industrial production conditions for diacetyl are mature, readily available, and economically applicable, meeting the requirements of sustainable green development. [Effects of the Invention]

[0019] Beneficial Effects: Compared to conventional techniques, the present invention has the following remarkable advantages: (1) This method uses diacetyl as the active substance, exhibits algal inhibitory and bactericidal effects under natural light alone, is highly selective, environmentally friendly, economical, and efficient. (2) The method is easy to operate. (3) Diacetyl is stable, safe, easy to transport, and does not require expert operation. (4) This method selectively inhibits Skeletonema costatum, its synonym, Microcystis erginosa, and red tide dinoflagellates, as well as Escherichia coli and Staphylococcus aureus. [Brief explanation of the drawing]

[0020] [Figure 1] These are diagrams showing the suppression of algal density of Microcystis erginosa, its synonym, Skeletonema costatum, and red tide dinoflagellates by diacetyl, as measured in Examples 1-4. [Figure 2] This diagram shows the inhibition of the growth process of Euglena by diacetyl, as measured in Comparative Example 1. [Figure 3] This diagram shows the inactivation effect of diacetyl on various initial densities of Microcystis erginosa, as measured in Example 5. [Figure 4] This diagram shows the inactivation effect of diacetyl on E. coli as measured in Example 6. [Figure 5] This diagram shows the inactivation effect of diacetyl on Staphylococcus aureus, as measured in Example 7. [Figure 6] This is a comparative diagram of the effects of diacetyl and other common algae inhibitors and bactericidal substances measured in Comparative Example 2. [Figure 7] The diacetyl measured in Example 8 is the electron paramagnetic resonance (EPR) spectrum under light irradiation. [Figure 8] This diagram shows the effect of diacetyl, measured in Examples 9 and 10, on treating harmful algae and fungi in natural water. [Modes for carrying out the invention]

[0021] The technical proposal of the present invention will be further described below based on examples.

[0022] The diacetyl used in the examples of this invention is for analytical purposes.

[0023] Some of the algae described in the examples of the present invention are unicellular red tide algae: synonyms, Skeletonema costatum and red tide dinoflagellates isolated from the East China coast, and freshwater algae: Microcystis erginosa FACHB-905 and Euphorbia fACHB-265 from the Wuhan Freshwater Algae Seed Bank of the Chinese Academy of Sciences. The red tide algae were cultured in f / 2 medium, and the freshwater algae were cultured in BG11 medium.

[0024] The bacteria described in the examples of the present invention are Escherichia coli DH5α and Staphylococcus aureus ATCC25923, both of which were cultured using LB broth medium.

[0025] The term "water" as used in this invention refers to ultrapure water without further explanation or limitation.

[0026] The main components of f / 2 medium are NaNO3, 75 mg / L; Na2SiO3·9H2O, 30 mg / L; NaH2PO4·3H2O, 5 mg / L; Na2EDTA·2H2O, 4.36 mg / L; FeCl3·6H2O, 3.15 mg / L; MnCl2·6H2O, 1.8 mg / L; Vitamin B1, 0.1 mg / L; ZnSO4·7H2O, 22 μg / L; CoCl2·6H2O, 10 μg / L; CuSO4·5H2O, 9.8 μg / L; Na2MoO4·2H2O, 6.3 μg / L; Biotin, 0.5 μg / L; and Vitamin B12, 0.5 μg / L.

[0027] The main components of BG11 medium are NaNO3, 1.5 g / L; MgSO4·7H2O, 0.075 g / L; CaCl2·2H2O, 0.036 g / L; K2HPO4·3H2O, 0.04 g / L; Na2CO3, 0.02 g / L; citric acid, 6 mg / L; ferric ammonium citrate, 6 mg / L; Na2EDTA, 1 mg / L; H3BO3, 2.86 mg / L; MnCl2·4H2O, 1.86 mg / L; ZnSO4·7H2O, 0.22 mg / L; Na2MoO4·2H2O, 0.39 mg / L; CuSO4·5H2O, 0.08 mg / L; and Co(NO3)2·6H2O, 0.05 mg / L.

[0028] The main components of LB meat juice culture medium are tryptone, 10 g / L, yeast extract, 5 g / L, and NaCl, 10 g / L.

[0029] In the above embodiment, the absorbance at 680 nm (OD) was measured using an ultraviolet spectrophotometer (UV-2700). 680 The algal inhibitory performance of diacetyl was evaluated by measuring the following parameters.

[0030] In the above embodiment, turbidity was measured using a turbidimeter (2100P), and the effectiveness of diacetyl in suppressing algae growth in natural water bodies was demonstrated.

[0031] Example 1: Inhibitory effect of diacetyl on synonyms In a sterile clean bench, synonyms in the exponential growth phase were inoculated into sterile 50 mL quartz reaction bottles and sterile 6-well plates, and their OD (Oral Size) was determined. 680 The ratio was set to 0.22, and then different volumes of diacetyl diluent (100 mM) were added to the reaction bottle and sterile 6-well plate to achieve final diacetyl concentrations of 0.2 mM, 0.4 mM, and 0.6 mM. A blank control group (CK) without diacetyl was also established. The quartz reaction bottle was sealed with clear film and exposed to sunlight (50 mW / cm²). 2 The plates were placed in a container. At the same time, a sterilized 6-well plate was placed in a dark place. After reaction for 0h, 2h, 4h, 6h, 8h, and 10h, samples were taken and OD (Oral Discharge). 680 Measured and the formula Y = 99.148 × OD680 -0.881 was used to calculate the algal cell density (Y, 10 5 cells / mL).

[0032] Example 2: Inhibitory effect of diacetyl on Skeletonema costatum Skeletonema costatum in the exponential growth phase was inoculated into sterilized 50 mL quartz reaction bottles and sterilized 6-well plates, and its OD 680 was adjusted to 0.14. Then, different volumes of diacetyl diluent (100 mM) were added to the reaction bottles and sterilized 6-well plates to make the final concentrations of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group without adding diacetyl was designed. The quartz reaction bottles were sealed with transparent films and placed in sunlight (50 mW / cm 2 ). At the same time, the sterilized 6-well plates were placed in the dark. After reacting for 0 h, 2 h, 4 h, 6 h, 8 h, and 10 h, samples were taken to measure OD 680 , and the algal cell density (Y, 10 680 cells / mL) was calculated according to Y = 33.612×OD 5 -0.546.

[0033] Example 3: Inhibitory effect of diacetyl on red tide dinoflagellates Under sterilized conditions, red tide dinoflagellates in the exponential growth phase were inoculated into sterilized 50 mL quartz reaction bottles and sterilized 6-well plates, and their OD 680 was adjusted to 0.14. Then, different volumes of diacetyl diluent (100 mM) were added to the reaction bottles and sterilized 6-well plates to make the final concentrations of diacetyl 0.2 mM, 0.4 mM, and 0.6 mM, and a blank control group without adding diacetyl was designed. The quartz reaction bottles were sealed with transparent films and placed in sunlight (50 mW / cm 2 ). At the same time, the sterilized 6-well plates were placed in the dark. After reacting for 0 h, 2 h, 4 h, 6 h, 8 h, and 10 h, samples were taken to measure OD 680 , and the algal cell density (Y, 10 680 cells / mL) was calculated according to Y = 20.609×OD 5 +0.091.

[0034] Example 4: Inhibitory effect of diacetyl on Microcystis erginosa Microcystis erginosa FACHB-905 in the exponential growth phase was inoculated into sterile 50 mL quartz reaction bottles and sterile 6-well plates, and the OD (Oral Species Dissociation) was performed. 680 The diacetyl solution was adjusted to 0.20, and then different volumes of diacetyl diluent (100 mM) were added to the reaction bottle and sterile 6-well plate to achieve final diacetyl concentrations of 0.2 mM, 0.4 mM, and 0.6 mM, creating a blank control group without diacetyl. The quartz reaction bottle was sealed with clear film and exposed to sunlight (50 mW / cm²). 2 The plates were placed in a container. At the same time, a sterilized 6-well plate was placed in a dark place. After reaction for 0h, 2h, 4h, 6h, 8h, and 10h, samples were taken and OD (Oral Discharge). 680 Measure Y = 28.660 × OD 680 Algal cell density (Y, 10) according to +0.078 6 The number of cells per mL was calculated.

[0035] The test results for Examples 1 to 4 are shown in Figure 1.

[0036] Figure 1 shows the algal density diagrams under which diacetyl inhibits the growth of the synonym (a), Skeletonema costatum (b), red tide dinoflagellate (c), and Microcystis erginosa (d) under light irradiation and dark conditions, respectively. As can be seen from Figure 1, when diacetyl was treated with the synonym, red tide dinoflagellate, and Microcystis erginosa for 2 hours under light irradiation, the effect was not clear and had little effect on the growth of algal cells. However, at this time, diacetyl showed a clear algal inhibitory effect on Skeletonema costatum. With increasing treatment time, diacetyl concentrations greater than 0.2 mM all reduced the algal density of the four types of algae, and the algal inhibitory effect increased with increasing concentration, with 0.6 mM diacetyl showing the best algal inhibitory effect. 0.2 mM diacetyl had little inhibitory effect on red tide dinoflagellates, but it effectively inhibited the other three types of algae, showing a sustained growth inhibitory effect within the treatment time range. Overall, the algal inhibitory effect of diacetyl was Skeletonema costatum > synonym, and Microcystis erginosa > red tide dinoflagellates. Compared to light-irradiated conditions, the algal densities of the four types of algae under various concentrations of diacetyl in the dark were not clearly distinguishable from the control group, indicating that diacetyl itself does not have a clear inhibitory effect on algal cells under various treatment concentrations.

[0037] Comparative Example 1: Inhibitory effect of diacetyl on Euglena Edamame FACHB-265 in the exponential growth stage was inoculated into sterile 50 mL quartz reaction bottles and sterile 6-well plates, and the OD (Oral Dissociation) was performed. 680 The diacetyl solution was adjusted to 0.20, and then different volumes of diacetyl diluent (100 mM) were added to the reaction bottle and sterile 6-well plate to achieve final diacetyl concentrations of 0.2 mM, 0.4 mM, and 0.6 mM, creating a blank control group without diacetyl. The quartz reaction bottle was sealed with clear film and exposed to sunlight (50 mW / cm²). 2 The plates were placed in a container. At the same time, a sterilized 6-well plate was placed in a dark place. After reaction for 0h, 2h, 4h, 6h, 8h, and 10h, samples were taken and OD (Oral Discharge). 680 Measure Y = 31.726 × OD680 Algal cell density (Y, 10) according to +0.087 5 The number of cells per mL was calculated. The test results are shown in Figure 2.

[0038] Figure 2 shows the change in algal density after treating Euglena pulcherrima with diacetyl for 10 hours under light irradiation and dark conditions in Comparative Example 1. As shown in the figure, diacetyl treatment did not affect the growth of Euglena pulcherrima, regardless of the presence or absence of sunlight. This indicates that Euglena pulcherrima has a stronger tolerance to diacetyl than the other four types of algae, and that diacetyl has the ability to selectively inhibit algae.

[0039] Example 5: Inactivation effect of diacetyl on Microcystis erginosa at various initial densities Microcystis erginosa FACHB-905 in the exponential growth phase was inoculated into sterile 50 mL quartz reaction bottles and sterile 6-well plates, and the OD (Oral Species Dissociation) was performed. 680 The concentrations were set to 0.1, 0.2, 0.3, and 0.4, respectively. Then, diacetyl diluent (100 mM) was added to the reaction bottle to achieve a final diacetyl concentration of 0.4 mM, and a blank control group without diacetyl was designed. The quartz reaction bottle was sealed with transparent film and exposed to sunlight (50 mW / cm²). 2 It was placed in ). After reaction for 0h, 2h, 4h, 6h, 8h, and 10h, a sample was taken and OD 680 Measure Y = 28.660 × OD 680 Algal cell density (Y, 10) according to +0.078 6 The number of cells per mL was calculated. The test results are shown in Figure 3.

[0040] Figure 3 shows the inhibitory effect of 0.4 mM diacetyl on Microcystis erginosa at various initial densities under sunlight. As can be seen from the figure, when the algal density of Microcystis erginosa is 3.1 × 10⁻⁶, 6 -1.1 × 10 7 In the cells / mL range, diacetyl was able to achieve significant algal suppression within 10 hours in all cases.

[0041] Example 6: Inactivation effect of diacetyl on E. coli E. coli DH5α was selected for inactivation experiments. E. coli solutions cultured at 37°C and 200 rpm until the logarithmic growth phase were centrifuged at 5000 rpm for 5 minutes. The supernatant was discarded, and the precipitate was collected. The bacterial precipitate was resuspended in sterile physiological saline (0.9% NaCl, pH 7.0) and centrifuged again. This step was repeated three times to completely remove any remaining culture medium. Finally, the precipitate was resuspended in sterile physiological saline to obtain a pure bacterial suspension, yielding 1.0 × 10⁶ of the precipitate. 7 Diluted to CFU / mL.

[0042] The above bacterial suspension was added to a quartz reaction tube, and different volumes of diacetyl were added to achieve final diacetyl concentrations of 0.01 mM, 0.1 mM, 0.2 mM, and 0.3 mM, establishing a blank control. The quartz reaction bottle was sealed with clear film and exposed to sunlight (50 mW / cm²). 2 The samples were placed in ) during the process. During processing, the reaction suspension was collected at regular time intervals, appropriately diluted, and 0.1 mL of the diluted sample was uniformly spread onto an LB agar plate. After incubation at 37°C for 24 hours, the number of colonies formed on the plate was counted.

[0043] Furthermore, 0.2 mM diacetyl was selected to assess its bactericidal effect against E. coli at various concentrations.

[0044] Resuspend the E. coli using the method described above, and 1.0 × 10 6 -1.0 × 10 8 The bacterial suspension was diluted to CFU / mL. The suspension was added to a quartz reaction tube, and 0.2 mM diacetyl was added to establish a blank control. Colony counting was performed by smearing. The test results are shown in Figure 4.

[0045] Figure 4 shows the inactivation effect of diacetyl on E. coli. As shown in Figure 4(a), when the concentration of diacetyl is 0.1 mM or higher, it shows excellent bactericidal effect, and the bactericidal effect is strengthened with increasing diacetyl concentration. From Figure 4(b), it can be seen that 0.2 mM diacetyl inactivates a colony density of 1.0 × 10⁻⁶. 6 -1.0 × 10 8It was found to have a good inactivating effect on E. coli at CFU / mL, and complete inactivation could be achieved within 75 minutes.

[0046] Example 7: Inactivation effect of diacetyl on Staphylococcus aureus Inactivation experiments were performed on Staphylococcus aureus ATCC25923, selected under the same culture conditions as Escherichia coli. A bacterial suspension from the logarithmic growth phase was collected and centrifuged (5000 rpm, 5 min). The supernatant was discarded, and the precipitate was collected. The bacterial precipitate was resuspended in sterile physiological saline (0.9% NaCl, pH 7.0) and centrifuged again. This step was repeated three times to completely remove any culture medium residue. Finally, the precipitate was resuspended in sterile physiological saline to obtain a pure bacterial suspension. The colony count was 1.0 × 10⁶. 7 Staphylococcus aureus at a concentration of CFU / mL was added to a quartz reaction tube, and 0.2 mM diacetyl was added. Experiments were conducted under sunlight and dark conditions to establish a blank control. The test results are shown in Figure 5.

[0047] Figure 5 shows the inactivation effect of diacetyl on Staphylococcus aureus. As shown in Figure 5(a), in addition to Escherichia coli (Gram-negative bacteria), diacetyl also has a clear inactivation effect on Staphylococcus aureus (Gram-positive bacteria), and irradiating it with sunlight for 120 minutes can completely inactivate Staphylococcus aureus.

[0048] Comparative Example 2: Comparison of the inhibitory effects of diacetyl and other common algae inhibitors and bactericidal substances on Microcystis erginosa. Based on the above experimental results, Microcystis erginosa was further selected as a representative species and comparative experiments were conducted. Microcystis erginosa FACHB-905 in the exponential growth phase was inoculated into a sterile 50 mL quartz reaction bottle, and its OD (Oral Size) was determined. 680 The concentration was set to 0.1. Subsequently, diacetyl, hydrogen peroxide, peroxyacetic acid, persulfate, and periodate were added to each reaction bottle to a final concentration of 0.4 mM, and a blank control group without the addition of algae-inhibiting substances was designed. The quartz reaction bottles were sealed with transparent film and exposed to sunlight (50 mW / cm²). 2It was placed in ). After reaction for 0h, 2h, 4h, 6h, 8h, and 10h, a sample was taken and OD 680 Measure Y = 28.660 × OD 680 Algal cell density (Y, 10) according to +0.078 6 The number of cells per mL was calculated. The test results are shown in Figure 6.

[0049] Figure 6 compares the inhibitory effects of diacetyl and other common algal inhibitors and fungicides on Microcystis erginosa. As can be seen from the figure, hydrogen peroxide and peroxyacetic acid-based strong oxidizers showed good algal inhibitory effects in the early stages. The effects of diacetyl, periodate, and persulfate were slower, but as the experiment progressed, diacetyl showed a clear algal inhibitory effect in the later stages, and its final algal inhibitory effect after 10 hours of treatment was superior to that of peroxyacetic acid and hydrogen peroxide.

[0050] Example 8: Electron paramagnetic resonance (EPR) spectrum under photoirradiation of diacetyl First, anaerobic water was prepared by placing ultrapure water in an oxygen-free glove box. A diacetyl solution was then prepared using a fixed amount of this anaerobic water. 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was added as a scavenging agent, mixed, and slowly added to a capillary quartz tube, which was then sealed with petrolatum. The capillary was placed in the cavity of the EPR apparatus, and in-situ irradiation was performed at a distance of approximately 1 m from the sample. The EPR signals of the sample were measured at 0 min and 5 min, and the test results are shown in Figure 7.

[0051] Figure 7 shows the EPR spectrum of diacetyl under photoirradiation. As shown in the figure, the EPR spectrum obtained under anaerobic conditions showed six major peaks from the DMPO-CH3C(O) adduct. In addition, a weaker peak belonging to DMPO-CH3 was also detected. Under aerobic conditions, CH3C(O) was able to rapidly bind with oxygen molecules to generate oxidative acetylperoxyl radicals.

[0052] Example 9: Effect of diacetyl on the treatment of Microcystis erginosa in natural water 30L of water from the Tianlai River (32°7′8″N, 118°56′67″E) containing Microcystis erginosa FACHB-905 (OD 680 0.6) 500 mL was added and cultured until the exponential growth stage. Then, an appropriate amount of diacetyl was added and mixed to bring the concentration of the treatment group to 0.5 mM, and at the same time, a blank control group without diacetyl was established. Samples were taken at regular intervals daily from day 0 to day 8, and the effect of diacetyl on inhibiting algae growth in natural water was measured by turbidity measurement. The test results are shown in Figure 8(a).

[0053] As can be seen in Figure 8(a), the control group of Microcystis erginosa grew vigorously, and its turbidity rose to 35 NTU on day 3 and was maintained at around 25 NTU for the next few days. In contrast, the experimental group treated with diacetyl showed a decrease in turbidity to below 10 NTU within one day and was maintained at a low level during the subsequent observation period.

[0054] Example 10: Effect of diacetyl on treating bacteria in natural water 20 L of water was collected from the Tianlai River (32°7′8″N, 118°56′67″E), filtered through gauze to remove impurities and plant residues, and then placed in a transparent polypropylene tank. The tank was left to stand in sunlight, and 0.2 mM diacetyl was added. Samples were taken periodically at 0, 2, 4, 6, 8, and 12 hours, appropriately diluted, and a 0.1 mL diluted sample was uniformly spread on a plate. After incubation at 37°C for 18 hours, the number of colonies formed on the plate was counted. The test results are shown in Figure 8(b).

[0055] As shown in Figure 8(b), the addition of diacetyl could rapidly inactivate bacteria in the aqueous solution at 6h, suggesting potential for practical applications.

Claims

1. A method for inhibiting algae growth and sterilization, characterized by adding diacetyl to the water to be treated and allowing it to act under sunlight irradiation to suppress the growth of algae and fungi.

2. The method for suppressing and sterilizing algae according to claim 1, characterized in that the aforementioned algae are Skeletonema costatum, a synonym, Microcystis erginosa, or red tide dinoflagellates.

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

4. The method for suppressing and sterilizing algae according to claim 2, characterized in that the concentration of the diacetyl in the treated water is 0.2 mM or higher.

5. The method for suppressing and sterilizing algae according to claim 3, characterized in that the concentration of the diacetyl in the treated water is 0.1 mM or higher.

6. The density range of the aforementioned algae is 4.4 × 10 5 ~1.1 x 10 7 The method for suppressing and sterilizing algae according to claim 2, characterized in that the concentration is cells / mL.

7. The method for suppressing and sterilizing algae according to claim 6, characterized in that, when the algae is Skeletonema costatum, the concentration of diacetyl in the treated water is 0.2 to 0.6 mM.

8. The method for suppressing and sterilizing algae according to claim 6, characterized in that, when the algae is a synonym or Microcystis erginosa, the concentration of diacetyl in the treated water is 0.2 to 0.6 mM.

9. The method for suppressing and sterilizing algae according to claim 6, characterized in that, when the algae are red tide dinoflagellates, the concentration of diacetyl in the treated water is 0.4 to 0.6 mM.

10. The density range of the aforementioned fungi is 3.6 × 10 3 ~1.0 x 10 8 The method for suppressing and sterilizing algae according to claim 3, characterized in that the concentration is CFU / mL.

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