Oxalic acid dihydrate-containing active treatment agent for seaweed cultivation

Abstract

To provide an active treatment agent for laver aquaculture containing oxalic acid dihydrate.SOLUTION: The present invention relates to an active treatment agent for laver aquaculture containing oxalic acid dihydrate, wherein a first active treatment agent containing oxalic acid dihydrate is superior in pitch removal capability, green laver removal capability, copepod removal capability, and cadmium removal capability, and, when mixed with a second active treatment agent that is activated chlorine dioxide aqueous solution, by confirming that harmful microorganisms belonging to the genus Pseudoalteromonas, which soften laver tissue, are markedly reduced, an active treatment agent for laver aquaculture that is environmentally friendly and excellent is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an active treatment agent for laver cultivation containing oxalic acid dihydrate. [Background technology]

[0002] Laver, a common staple food, is known for its low cost, delicious taste, and excellent nutrition, making it a popular seaweed food enjoyed by people of all ages and genders. Laver is known to be rich in protein, iron, calcium, and vitamins, including vitamin A, which is good for eye health, and contains ingredients that prevent aging and cancer, making it an excellent health food. Laver is also rich in dietary fiber, promoting the excretion of toxic substances such as carcinogens and waste products, and preventing adult diseases such as diabetes and obesity. Laver cultivation accounts for the majority of seaweed cultivation in Korea. Laver is a collective term for Porphyra dentata, Porphyra seriata, and Porphyra yezoensis, which belong to the family Bangiocarpaceae and the order Bangiolelate. In South Korea, seaweed is cultivated in Goheung County, Sinan County, Wando County, Jindo County, Haenam County, and Buan County in South Jeolla Province.

[0003] Nori cultivation is carried out using two methods: pole-based and floating-type. The pole-based method utilizes the tides by fixing poles to shallow seawater and attaching seaweed cultivation nets to the poles. During high tide, the nets are submerged, and during low tide, the nets are exposed. This allows sunlight to shine on properly cultivated seaweed, facilitating optimal photosynthesis. Furthermore, exposed nets are sterilized by ultraviolet light and naturally dried, reducing disease and enabling the production of high-quality seaweed. However, the areas with the appropriate tides for seaweed cultivation are limited, and the constant flow of seawater weakens the poles, limiting the long-term and large-scale cultivation of seaweed using the pole-based method. Meanwhile, the floating-type method involves fixing nets to deep seawater and cultivating seaweed in a manner that keeps them constantly submerged. The floating method allows for mass production, but because the nets are constantly submerged in water, they are prone to disease and require constant maintenance.More than 90% of seaweed farming in Korea is done using the floating method, and artificial processing is used to prevent disease and remove diatoms and green seaweed.

[0004] In conventional seaweed cultivation, impurities have been removed by treating seaweed with acidic substances to promote seaweed growth, eliminate weeds, and prevent diseases such as green seaweed and diatoms. However, the conventional use of hazardous substances such as concentrated hydrochloric acid has been negatively perceived by consumers, raising concerns about food safety and marine pollution. Acid treatment using inorganic acids removes impurities by passing hydrochloric acid diluted in seawater through aquaculture nets in which seaweed grows, as described above. However, the diluted hydrochloric acid solution flows into the sea, impacting the marine ecosystem, and the hydrochloric acid remains in the cultivated seaweed, posing a threat to consumer health.

[0005] As a result, organic acid-based activators such as citric acid have been developed. Citric acid-based activators have lower performance than inorganic acids, requiring four times more treatment and longer treatment times than inorganic acids, resulting in increased seaweed cultivation time and costs. Citric acid has a pKa of 3.0 dml, but given the pH of 1.0 or less required for seaweed cultivation, citric acid-based activators have inherent limitations. Furthermore, because conventional citric acid-based seaweed activators are organic, they can be decomposed into carbon dioxide by marine microorganisms, potentially depleting dissolved oxygen in seawater. The buffering properties of citric acid neutralize the citric acid-based seaweed activators after use, but they require 10 times more seawater than inorganic acids of the same activity, potentially causing ocean acidification. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Republic of Korea Patent Publication No. 10-2013-0059376 (published on June 5, 2013)

[0007] [Patent Document 2] Republic of Korea Patent No. 10-2495937 (Announced on February 6, 2023) Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide an oxalic acid-based active treatment agent for Nori cultivation, which is effective in promoting Nori growth, removing weeds, and preventing diseases in Nori cultivation areas, while minimizing marine pollution. [Means for solving the problem]

[0009] The present invention provides an active treatment agent for laver cultivation containing oxalic acid dihydrate.

[0010] The present invention also provides a method for producing an activating treatment agent for seaweed cultivation, comprising the steps of: mixing oxalic acid dihydrate with water to prepare a mixed solution (step 1); and adding hydrochloric acid to the mixed solution and stirring the mixture to prepare a first activating treatment agent (step 2).

[0011] The present invention also provides a method for using an activating treatment agent for Nori cultivation, which comprises diluting a first activating treatment agent for Nori cultivation containing oxalic acid dihydrate with seawater for treatment. [Effects of the Invention]

[0012] According to the present invention, the first active treatment agent containing oxalic acid dihydrate is excellent in removing tar (grease), green laver, copepods, and cadmium, and when mixed with the second active treatment agent, which is activated chlorine dioxide water, it has been confirmed that harmful microorganisms belonging to the genus Pseudoalteromonas, which soften laver tissue, are significantly reduced, thereby providing an environmentally friendly and excellent active treatment agent for laver cultivation. [Brief explanation of the drawings]

[0013] [Figure 1] These are the results of an evaluation of the tar removal ability of the first active treatment agent for seaweed cultivation containing oxalic acid dihydrate.

[0014] [Figure 2] These are the results of evaluating the ability of the first active treatment agent for seaweed cultivation containing oxalic acid dihydrate to remove green seaweed.

[0015] [Figure 3] These are the results of an evaluation of the copepod removal ability of the first active treatment agent for seaweed cultivation containing oxalic acid dihydrate.

[0016] [Figure 4] These are the results of an evaluation of the cadmium removal ability of the first active treatment agent for seaweed cultivation containing oxalic acid dihydrate.

[0017] [Figure 5]This shows the results of evaluating the ability of the first active treatment agent for seaweed cultivation containing oxalic acid dihydrate to remove green seaweed depending on the type and concentration of gums mixed in, as measured by changes in pH.

[0018] [Figure 6] The results show that the ability to remove green laver depending on the type and concentration of gums mixed into the first active treatment agent for laver cultivation containing oxalic acid dihydrate was evaluated using changes in color difference meter.

[0019] [Figure 7] These are the results of evaluating the effect of reducing harmful microorganisms by mixing a first active treatment agent for seaweed cultivation containing oxalic acid dihydrate with a second active treatment agent, which is activated chlorine dioxide water.

[0020] [Figure 8] These are the results of a metagenomic evaluation of the effectiveness of mixing a first active treatment agent for seaweed cultivation containing oxalic acid dihydrate with a second active treatment agent, which is activated chlorine dioxide water, in reducing harmful microorganisms.

[0021] [Figure 9] These are the results of an evaluation of the ability to remove resin stuck to Nori fascicles by mixing a first active treatment agent for Nori cultivation containing oxalic acid dihydrate and a second active treatment agent, activated chlorine dioxide water. DETAILED DESCRIPTION OF THE INVENTION

[0022] The terms used in this specification have been selected as widely used and general terms as possible while taking into consideration the functions of the present invention, but this may change depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. In addition, in certain cases, the applicant may arbitrarily select terms, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this specification should be defined based on the meanings of the terms and the overall content of the present invention, rather than simply by the names of the terms.

[0023] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art. Terms as defined in commonly used dictionaries should be interpreted to have a meaning consistent with the context of the relevant art, and should not be interpreted as idealized or overly formal unless expressly defined herein.

[0024] The present invention will now be described in more detail.

[0025] The inventors of the present invention aim to improve the quality and productivity of Nori seaweed, while at the same time contributing to the protection of the marine environment through an environmentally friendly approach. They have developed an "activator for Nori seaweed cultivation" that offers superior performance in removing weeds, preventing diseases, and promoting growth of cultivated Nori seaweed. The present inventors have developed a new oxalic acid-based activator for Nori seaweed. The oxalic acid-based activator not only has excellent acidity and disease control effects, but is also mixed with gums to improve adhesion. When mixed with activated chlorine dioxide (or its raw material, sodium chlorite, NaClO2), the activator's pest control effects are enhanced. The oxalic acid-based activator exhibits improved acidity retention compared to conventional citric acid-based activators, and through a mixed treatment method using oxalic acid and chlorine dioxide, it effectively promotes Nori seaweed growth, removes weeds, and prevents diseases, even at one-third the amount of concentrated hydrochloric acid, compared to concentrated hydrochloric acid. Activated chlorine dioxide water has a strong bactericidal effect and effectively removes harmful microorganisms from cultivated seaweed with only a small amount, and the photodecomposition properties of chlorine dioxide minimize environmental pollution. Therefore, the combined use of an oxalic acid-based seaweed activator and chlorine dioxide water according to the present invention provides an innovative solution for managing seaweed farms and contributes to the development of a sustainable seaweed farming industry.

[0026] The activating treatment agent according to the present invention refers to a substance containing any one of organic acids, acidic electrolyzed water, nutrients, and highly saline water as its main ingredient, which is used to remove weeds, prevent diseases, and promote growth in laver farms.

[0027] The present invention provides an active treatment agent for laver cultivation containing oxalic acid dihydrate.

[0028] The active treatment agent for Nori cultivation contains 10 to 20% by weight of oxalic acid dihydrate and 3 to 5% by weight of hydrochloric acid. Preferably, the active treatment agent for Nori cultivation contains 13.4% by weight of oxalic acid dihydrate and 4.53% by weight of hydrochloric acid.

[0029] The active treatment agent for Nori cultivation may contain 0.001 to 0.005% by weight of gum arabic or 0.001 to 0.005% by weight of xanthan gum. Preferably, the active treatment agent for Nori cultivation may contain 0.002 to 0.001% by weight of gum arabic and 0.003 to 0.004% by weight of xanthan gum.

[0030] The present invention also provides a method for producing an activating treatment agent for seaweed cultivation, comprising the steps of: mixing oxalic acid dihydrate with water to prepare a mixed solution (step 1); and adding hydrochloric acid to the mixed solution and stirring the mixture to prepare a first activating treatment agent (step 2).

[0031] The first active processing agent contains 10 to 20% by weight of oxalic acid dihydrate and 3 to 5% by weight of hydrochloric acid, and the first active processing agent may further contain 0.001 to 0.005% by weight of gum arabic or 0.001 to 0.005% by weight of xanthan gum.

[0032] The method may further include the steps of: mixing aqueous chlorine dioxide and citric acid to prepare a second active treatment agent; and mixing the first active treatment agent and the second active treatment agent.

[0033] The second active treatment agent contains 5 to 10% by weight of chlorine dioxide water and 2 to 5% by weight of citric acid.

[0034] The first and second active treatment agents are mixed in a 100:1 ratio.

[0035] The first and second active treatment agents are mixed in an unsealed container and then exposed to the air for 20 minutes to 1 hour.

[0036] The method may further include the steps of preparing a third active treating agent containing sodium chlorite solution, and mixing the first and third active treating agents. The third active treating agent is prepared by mixing 25% sodium chlorite solution, a raw material for chlorine dioxide, with the first active treating agent at a weight ratio of 1 / 200, and exposing the mixture to air for 20 minutes to 1 hour to generate chlorine dioxide.

[0037] The present invention also provides a method for using an activating treatment agent for Nori cultivation, which comprises diluting a first activating treatment agent for Nori cultivation containing oxalic acid dihydrate with seawater for treatment.

[0038] In one embodiment of the present invention, the first active treatment agent is diluted 20 to 120 times with seawater before treatment.

[0039] In another embodiment of the present invention, a first active treating agent for Nori cultivation containing oxalic acid dihydrate is mixed with a second active treating agent for Nori cultivation (chlorine dioxide water or its raw material sodium chlorite) containing chlorine dioxide water and citric acid to prepare a mixed treating agent, which is then diluted 100 to 200 times with seawater depending on the maturity of the Nori. The Nori cultivation net is immersed in the mixed treating agent for 5 to 10 seconds, and then removed and exposed to air for 10 to 15 seconds.

[0040] The first active treatment agent, an oxalic acid-based treatment agent, can be diluted with seawater at an appropriate ratio before use. Preferably, the first active treatment agent, an oxalic acid-based treatment agent, is diluted at a ratio of 1 / 40 based on the mature laver leaf. The first active treatment agent, an oxalic acid-based treatment agent, is mixed with the second or third active treatment agent, which is activated chlorine dioxide water, to prepare a mixed treatment agent before use. The recommended dilution ratio of the mixed treatment agent is 1 / 100 based on the mature laver leaf. This provides improved acidity compared to conventional citric acid-based laver active treatment agents, further promoting the growth of cultivated laver, eliminating weeds, and preventing diseases.

[0041] Hereinafter, the present invention will be described in detail with reference to experimental examples and examples to aid in understanding the present invention. However, the following experimental examples and examples are merely illustrative of the content of the present invention, and the scope of the present invention is not limited to the following experimental examples and examples. The experimental examples and examples of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0042] [Production Example 1] First activating treatment agent

[0043] To prepare the first active treatment agent, an oxalic acid-based treatment agent, 2.68 kg of oxalic acid dihydrate and gum additives were dissolved in distilled water, followed by the addition of 2.55 L of 35.5% concentrated hydrochloric acid. While stirring, distilled water was added to bring the final volume to 20 L. The final first active treatment agent contained 13.4 wt% oxalic acid dihydrate and 4.53% hydrochloric acid, and was mixed with gum arabic and xanthan gum as gum additives. Depending on the mixing ratio of the gum additives, the following examples were prepared. When the first active treatment agent, an oxalic acid-based treatment agent prepared in the above examples, was used in seaweed farms, it was diluted 1 / 20 to 1 / 40 with seawater for treatment.

[0044] Example 1: 13.4% by weight of oxalic acid dihydrate and 4.53% hydrochloric acid

[0045] Example 2: 13.4% by weight oxalic acid dihydrate, 4.53% hydrochloric acid, and 0.005% gum arabic

[0046] Example 3: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.004% gum arabic, and 0.001% xanthan gum

[0047] Example 4: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.003% gum arabic, and 0.002% xanthan gum

[0048] Example 5: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.002% gum arabic, and 0.003% xanthan gum

[0049] Example 6: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.001% gum arabic, and 0.004% xanthan gum

[0050] Example 7: 13.4% by weight oxalic acid dihydrate, 4.53% hydrochloric acid, and 0.005% xanthan gum

[0051] [Production Example 2] Second activating treatment agent

[0052] The second activated treatment agent, which is activated chlorine dioxide water, was produced by mixing 0.2 L of 8% chlorine dioxide water with 0.02 L of 30% edible citric acid solution. The final produced second activated treatment agent contained 7.3 wt% chlorine dioxide water and 2.7 wt% citric acid. The second activated treatment agent, which is activated chlorine dioxide water, was mixed with the first activated treatment agent, which is an oxalic acid-based treatment agent, for treatment.

[0053] 20 L of the first active treatment agent, an oxalic acid-based treatment agent, was mixed with 0.2 L of the second active treatment agent, an activated chlorine dioxide solution, 30 minutes before use. The lid of the mixing container was left open so that it was not completely sealed. Based on the mature Nori thallus, 2 tons of seawater was placed in an immersion tank, and 20.2 L of the mixed first and second active treatment agents was added to create a final treatment agent at a dilution ratio of 1 / 100 with seawater. The pH of the final treatment agent was 1.5, and the chlorine dioxide level was 10 ppm. The Nori thallus was immersed in the final treatment agent for 5-7 seconds, exposed to air for 10-15 seconds, and then returned to seawater for aquaculture.

[0054] [Production Example 3] Third activating treatment agent

[0055] The third activated treatment agent, activated chlorine dioxide water, is manufactured from a 25% sodium chlorite solution, the raw material for chlorine dioxide water, purchased from Sigma-Aldrich as sodium chlorite (product number 814815). The first activated treatment agent was mixed with the third activated treatment agent, a 25% sodium chlorite solution stock solution, at a ratio of 1:200. It was confirmed that the chlorine dioxide level was similar to that in the solution produced in Preparation Example 2.

[0056] [Experimental Example 1] Evaluation of tar removal ability

[0057] The tar removal ability of the prepared oxalic acid-based treatment agent, the first active treatment agent, was evaluated at a seaweed farm in Hainan. To compare the effectiveness, a commonly used hydrochloric acid treatment agent was used in Comparative Example 1, and the removal of tar was analyzed.

[0058] Comparative Example 1: 35.5% by weight of hydrochloric acid

[0059] In seaweed farms, tar is a white, fouling organism that forms on the surface of seaweed. It must be removed because it can cause problems that not only affect the quality of the seaweed but also its marketability. Separate seaweed farms were treated with the treatment agent of Example 1 or Comparative Example 1 at a 40:1 dilution ratio, and samples were collected from each seaweed farm after 10 seconds of treatment. A control sample was used, and the seaweed and debris floating in the collected samples were analyzed under a microscope to confirm whether the tar had been removed. As shown in Figure 1, the presence of tar was confirmed in the seaweed and debris of the control sample. However, no tar was detected in the seaweed treated with Example 1 (oxalic acid treatment agent) or Comparative Example 1 (hydrochloric acid treatment agent), and fragments of the tar were found in the debris.

[0060] [Experimental Example 2] Evaluation of green seaweed removal ability

[0061] The first active treatment agent, which is an oxalic acid-based treatment agent, was evaluated for its ability to remove green laver. To simulate the on-site treatment environment of a laver farm, the ability to remove green laver was evaluated with and without stirring. To compare the effectiveness, a commonly used treatment agent containing 0.8% hydrochloric acid and a treatment agent containing citric acid were used as comparative examples.

[0062] Example 1: 13.4% by weight oxalic acid dihydrate and 4.53% hydrochloric acid, 1 / 40 diluted (stirred) / 1 / 40 diluted oxalic acid (not stirred)

[0063] Comparative Example 2: 0.8% hydrochloric acid, diluted 1 / 40 (without stirring)

[0064] Comparative Example 3: 10% citric acid and 9.5% hydrochloric acid, 1 / 40 dilution (stirred) / 1 / 40 dilution (not stirred)

[0065] A solution (simulating seawater) was prepared in advance by mixing 1 L of sterilized water with 35 g of sea salt and sterilizing it in an autoclave. Collected laver and green laver were placed in cold seawater stored at 2.4°C and then incubated in a freezer at 15°C for 2-3 hours. Approximately 100 g of laver and green laver were extracted and treated with the solutions of each example or comparative example. A control group (not using a stirrer) and experimental groups were immersed in a beaker containing the treatment solution. After the set treatment time, the treated laver and green laver were removed and washed with clean seawater to remove the adhering active agent. Treatment times were 5, 15, 20, 25, 30, and 35 seconds. Portions of the treated laver and green laver were collected and placed on glass slides, and the color difference between the laver and green laver and the control group was compared using a colorimeter.

[0066] As shown in Figure 2, in the case of hydrochloric acid treatment, a rapid color change occurred within just 5 seconds of treatment, confirming the death of the green laver. In the case of citric acid treatment, when treated at a 1 / 40 dilution ratio, the treatment effect on the green laver was confirmed to be much lower than that of hydrochloric acid treatment, regardless of whether it was stirred or not. On the other hand, in the case of oxalic acid treatment, when treated at a 1 / 40 dilution ratio without stirring, the death rate on the green laver was similar to that of citric acid, but when stirred, the death rate was confirmed to be 80% of that of hydrochloric acid treatment.

[0067] [Experimental Example 3] Evaluation of copepod removal ability

[0068] The copepod-eliminating ability of the prepared oxalic acid-based treatment agent, the first active treatment agent, was evaluated. The copepods used in the experiment were Daphnia magna purchased from Hansem Science. Mothers aged two weeks or more were selected and used. Daphnia were exposed to tubes containing 1 ml of each treatment agent from Example 1 and Comparative Example. Immediately after exposure, they were observed under a microscope, and the time to immobilization and death was recorded. When observed under a microscope, they actively moved, but then gradually became immobilized. After the heart was stopped, seizures were observed within one minute. The time when cardiac movement ceased was considered the time when cardiac arrest occurred. If there was no movement for one minute after a specific movement, this was considered the final movement and the time to death.

[0069] Example 1: 13.4% by weight oxalic acid dihydrate and 4.53% hydrochloric acid, 1 / 30 dilution (pH 1.0) / 1 / 20 dilution (pH 0.7)

[0070] Comparative Example 4: 7% hydrochloric acid (1 / 5 dilution of 35.5% hydrochloric acid stock solution)

[0071] Comparative Example 5: 0.88% hydrochloric acid (pH 0.5, 1 / 40 dilution of 35.5% hydrochloric acid stock solution)

[0072] Comparative Example 6: 10% citric acid and 9.5% hydrochloric acid, 1 / 30 dilution (pH 1.0) / 1 / 20 dilution (pH 0.7)

[0073] Comparative Example 7: After adding 1% chlorine citrate and 2% trisodium citrate, dilute the appropriate solution 1 / 20 / 1 / 10 using NaOH to make the pH 6.

[0074] As shown in Figure 3, it was confirmed that the copepods died within one minute of treatment with hydrochloric acid. With citric acid or chlorine-based treatments, it took more than five minutes for the copepods to die, and with citric acid, it was confirmed that the copepods died within five minutes only when diluted 1 / 20. Meanwhile, with oxalic acid, even at a 1 / 30 dilution, a similar level of killing effect to that of hydrochloric acid was observed.

[0075] [Experimental Example 4] Evaluation of cadmium removal ability

[0076] The cadmium removal ability of the first active treatment agent, which is an oxalic acid-based treatment agent, was evaluated using pole-cultivated Nori and general Nori.

[0077] Control group: no treatment

[0078] Example 1: 13.4% by weight of oxalic acid dihydrate and 4.53% hydrochloric acid (40x diluted)

[0079] Comparative Example 2: Hydrochloric acid 0.8%

[0080] Comparative Example 8: Solutions suitable for pH 7.5 and pH 6.5 using 0.2% by weight citric acid and hydrochloric acid

[0081] 30 g of laver was incubated in seawater at 15°C for 10 minutes. It was treated with 75 ml of each of the treatments from Example 1 or Comparative Example (hydrochloric acid and oxalic acid for 30 seconds, seawater and citric acid for 30 minutes). It was washed in seawater for 30 minutes. After rinsing with distilled water, it was placed in a 60°C incubator and dried with hot air. The dried samples were pulverized and submitted for inductively coupled plasma mass spectrometry (ICP-MS) analysis at the Joint Institute for Agricultural and Life Sciences, College of Agriculture and Life Sciences, Seoul National University. ICP-MS separates and detects ionized particles of each element based on their mass, and the cadmium content of each sample was analyzed. As shown in Figure 4, the oxalic acid treatment prepared according to the present invention was confirmed to remove cadmium to a level similar to that of hydrochloric acid.

[0082] [Experimental Example 5] Evaluation of the ability of the first active treatment agent to remove green laver depending on the mixing ratio of gums

[0083] The ability of green laver to be removed was evaluated depending on the type and concentration of gums mixed with the first active treatment agent, which is the prepared oxalic acid-based treatment agent. The gums mixed with the first active treatment agent increase the amount of treatment agent attached to the green laver, thereby enhancing the treatment effect. Green laver was immersed in the treatment agent of the Example or Comparative Example for 10, 30, and 60 seconds, and then observed. 100g of green laver was first added, and then one-third of it was removed at 10, 30, and 60 seconds. The laver was then transferred to seawater and rinsed for 30 seconds, and then transferred back to clean seawater and stirred, and the acidity of the solution was measured.

[0084] Example 1: 13.4% by weight of oxalic acid dihydrate and 4.53% hydrochloric acid (40x diluted)

[0085] Example 2: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, and 0.005% gum arabic (40x dilution)

[0086] Example 3: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.004% gum arabic, and 0.001% xanthan gum (40-fold dilution)

[0087] Example 5: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.002% gum arabic, and 0.003% xanthan gum (40-fold dilution)

[0088] Example 6: 13.4% by weight of oxalic acid dihydrate, 4.53% hydrochloric acid, 0.001% gum arabic, and 0.004% xanthan gum (40-fold dilution)

[0089] Example 7: 13.4% by weight oxalic acid dihydrate, 4.53% hydrochloric acid, and 0.005% xanthan gum (40x dilution)

[0090] Comparative Example 2: Hydrochloric acid 0.8%

[0091] Comparative Example 3: 10% citric acid and 9.5% hydrochloric acid (40 times diluted)

[0092] As shown in Figure 5, the adhesion of the oxalic acid treatment agent to the green laver was evaluated through the decrease in pH over time, and it was found that the combination of gum arabic and xanthan gum had a superior effect on decreasing pH over time compared to treatment with a single gum. Measurements of the hydrogen ion concentration released into the water over the same period showed that the green laver treated with the active treatment agent containing gums released even more acid. In other words, it was confirmed that a larger amount of the active treatment agent adhered to the green laver when gums were added.

[0093] The laver was immersed in the treatment for 20, 40, 60, and 80 seconds, then transferred to seawater and rinsed for 30 seconds, after which ΔE was calculated using a colorimeter. ΔE is the degree of color difference compared to the control group and was calculated using the following equation 1.

[0094]

number

[0095] (L: Lightness, A: Redness, B: Yellowness)

[0096] As shown in FIG. 6, the mortality of green laver was evaluated through a time-dependent colorimeter experiment. As a result, it was found that a combination of gum arabic and xanthan gum exhibited an excellent level of mortality, with Example 5 (0.002% gum arabic and 0.003% xanthan gum) and Example 6 (0.001% gum arabic and 0.004% xanthan gum) exhibiting the most excellent mortality.

[0097] [Experimental Example 6] Evaluation of harmful microorganism removal ability when mixed with the first and second active treatment agents

[0098] The ability to remove harmful microorganisms by a mixed treatment of the first active treatment agent, which is an oxalic acid-based treatment agent, and the second active treatment agent, which is activated chlorine dioxide water, was evaluated at a laver farm in Goheung and a laver farm in Jindo. The treatment method for the experimental groups was the same as described in Preparation Example 2. An untreated group was used as a control.

[0099] Metagenomic analysis detected Pseudoalteromonas, a species that can cause algae perforation disease at water temperatures above 10°C. The reduction of harmful microorganisms was assessed by analyzing the distribution of resident microorganisms on the surface of seaweed before and after treatment. Seaweed samples were collected from seaweed farms just before the onset of rot disease due to high water temperatures. One kilogram each was sampled along with clean seawater after treatment with the oxalic acid treatment agent (approximately pH 1.5-2.0) and chlorine dioxide (approximately 15-20 ppm). 25 g of collected seaweed was placed in a Stomacher filter bag with 225 mL of sterilized PBS and homogenized using a Stomacher. The homogenate was diluted and plated on marine agar at the appropriate dilution ratio. After incubation at 25°C for up to one week, bacterial colonies were measured. As shown in Figure 7, the levels of resident microorganisms were significantly reduced in the experimental group compared to the untreated control group.

[0100] The specific metagenomics experiment method for analyzing the reduction of harmful microorganisms was as follows. Seaweed samples were collected from seaweed farms immediately before the onset of rot due to high water temperatures. One kilogram each was sampled together with clean seawater after treatment with the oxalic acid treatment agent (approximately pH 1.5-2.0) and chlorine dioxide solution (approximately 15-20 ppm) prepared above. 25 g of collected seaweed was placed in a sterile filter bag with 225 mL of sterilized PBS and homogenized using a homogenizer. 40 mL of the homogenate was centrifuged (4,500 x g, 20 min, 4°C), the supernatant was discarded, and the pellet was collected. DNA was extracted from the pellet using a DNeasy mericon Food Kit (QIAGEN, Germany) and stored in an ultra-low temperature freezer (-80°C) until analysis. 16s rRNA amplicon sequencing (metagenomics) was performed using an Illumina MiSeq 2x300. Analysis was carried out using the Qiime2 pipeline.

[0101] As shown in Figure 8, the metagenome analysis revealed that the number of microorganisms belonging to the genus Pseudoalteromonas, which softens seaweed tissue, was significantly reduced in the treatment group.

[0102] [Experimental Example 7] Evaluation of tar removal ability when mixing the first and second active treatment agents

[0103] The tar removal ability of the mixed treatment using the first activated treatment agent, an oxalic acid-based treatment agent, and the second activated treatment agent, an activated chlorine dioxide solution, was evaluated. A 20.2 L mixture of the first and second activated treatment agents was added and diluted with seawater at a 1 / 100 ratio to create a final treatment agent. The final treatment agent had a pH of 1.5 and a chlorine dioxide concentration of 10 ppm. The laver fascines were immersed in the final treatment agent for 5-7 seconds, exposed to air for 10-15 seconds, and then returned to seawater for aquaculture. As shown in Figure 9, it was confirmed that the mixed treatment agent effectively removed the tar adhering to the laver fascines compared to the untreated state.

[0104] Although the specific details of the present invention have been described above, it will be apparent to those skilled in the art that such specific details are merely preferred embodiments and should not be construed as limiting the scope of the present invention, and the true scope of the present invention is defined by the claims and their equivalents.

[0105] Numerical ranges are inclusive of the numerical values ​​defined in the range. Every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitation were expressly written. Every minimum numerical limitation given throughout this specification includes every higher numerical limitation, as if such higher numerical limitation were expressly written. Every numerical limitation given throughout this specification includes every finer numerical range within the broader numerical range, as if such narrower numerical limitation were expressly written.

Claims

1. An active treatment agent for laver cultivation, which is obtained by diluting a first active treatment agent containing 13.4% by weight of oxalic acid dihydrate, 4.53% by weight of hydrochloric acid, and 0.001 to 0.005% by weight of gum arabic or xanthan gum with seawater at a ratio of 1 / 20 to 1 / 40.

2. A step of mixing oxalic acid dihydrate with water to produce a mixed solution (first step); A step (second step) of adding hydrochloric acid to the mixed solution and stirring to prepare a first activated treating agent; A method for producing an activating treatment agent for laver cultivation, comprising: The method for producing an active treatment agent for Porphyra aquaculture is an active treatment agent for Porphyra aquaculture, which is obtained by diluting a first active treatment agent containing 13.4% by weight of oxalic acid dihydrate, 4.53% by weight of hydrochloric acid, and 0.001 to 0.005% by weight of gum arabic or xanthan gum with seawater at a ratio of 1 / 20 to 1 / 40.

3. The method includes the steps of preparing a second activated treatment agent containing chlorine dioxide water and citric acid; mixing the first and second active treatment agents; The method for producing an activating treatment agent for laver cultivation according to claim 2, further comprising:

4. 4. The method for producing an activating treatment agent for laver cultivation according to claim 3, wherein the second activating treatment agent contains 5 to 10% by weight of chlorine dioxide water and 2 to 5% by weight of citric acid.

5. 4. The method for producing an activator for laver cultivation according to claim 3, wherein the first activator and the second activator are mixed in a ratio of 100:

1.

6. The method includes the steps of preparing a third activated treatment agent containing sodium chlorite; mixing the first active treatment agent and the third active treatment agent; The method for producing an activating treatment agent for laver cultivation according to claim 2, further comprising:

7. The method for producing an activator treatment agent for laver cultivation according to claim 6, wherein the third activator treatment agent contains a solution of 23 to 25% by weight of sodium chlorite.

8. 7. The method for producing an activator for laver cultivation according to claim 6, wherein the first activator and the third activator are mixed in a ratio of 200:

1.

9. 4. The method for producing an active treatment agent for laver cultivation according to claim 3, wherein the first active treatment agent and the second active treatment agent are mixed in an open container and then exposed to air for 20 minutes to 1 hour.

10. A method for using an active treatment agent for Porphyra aquaculture, characterized in that a first active treatment agent for Porphyra aquaculture containing 13.4% by weight of oxalic acid dihydrate, 4.53% by weight of hydrochloric acid, and 0.001 to 0.005% by weight of gum arabic or xanthan gum is diluted with seawater at a ratio of 1 / 20 to 1 / 40 and then treated.

11. A method for using an active treatment agent for Porphyra aquaculture, comprising: mixing a first active treatment agent for Porphyra aquaculture, which contains 13.4% by weight of oxalic acid dihydrate, 4.53% by weight of hydrochloric acid, and 0.001 to 0.005% by weight of gum arabic or xanthan gum, with a second active treatment agent containing aqueous chlorine dioxide and citric acid or a third active treatment agent containing sodium chlorite to produce a mixed treatment agent; and diluting the mixed treatment agent 100 to 200 times with seawater before use.

12. 12. A method for using the activating treatment agent for laver cultivation according to claim 11, characterized in that a laver cultivation net is immersed in the mixed treatment agent for 5 to 10 seconds, and then the laver cultivation net is pulled up and exposed to air for 10 to 15 seconds.

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