A kind of facultative anoxic deodorizing strain and its application

Abstract

The present invention discloses a facultative anaerobic deodorizing strain and its application. The strain is named Bacillus sp. K2F and is deposited in the General Microbiological Center of China Microorganism Culture Collection Administration Committee with the deposit number of CGMCC No. 26416. The strain disclosed in the present invention can effectively degrade most volatile fatty acids under anaerobic conditions, and can well reduce nitrate to ammonium (DNRA: Dissimilatory Nitrate Reduction to Ammonium, with nitrite as an intermediate product). Under aerobic conditions, butyric acid and ammonium substances can be removed, but the degradation ability of other substances is weaker than that under anaerobic conditions. The strain can be used for in-situ biological odor treatment and ex-situ biological odor treatment under anaerobic conditions after expansion culture by directed domestication.

Description

Technical Field

[0001] The invention belongs to the field of environmentally friendly water treatment and deodorization, and relates to an anaerobic deodorizing bacterial strain and application thereof. Background Art

[0002] Sewage treatment is an important part of my country's water resource cycle and an important barrier to ensure the safety of natural water. As sewage treatment technology becomes more and more complete, my country has made corresponding requirements for various emission indicators related to sewage treatment. However, the odor associated with sewage treatment technology can easily bring negative impacts on the production and life of the surrounding people.

[0003] In addition, the sewage treatment process inevitably has anoxic reaction pools, or unintentional anoxic areas formed due to poor design and operating conditions. Organic matter is prone to produce corrupt odors under anoxic conditions, further increasing the amount of odor released during the sewage treatment process.

[0004] In response to this situation, there are a variety of odor treatment methods at home and abroad. At present, the mainstream deodorization technologies used at home and abroad include biological deodorization, chemical washing deodorization, physical adsorption, chemical adsorption reaction, high-energy ion deodorization, etc. Biological deodorization has stable effect, large processing capacity, and low operation and maintenance cost, so the most widely used deodorization technology at home and abroad is biological deodorization.

[0005] The research on biological treatment of odor began in the 1950s. Various microbial reactions were used to react odor substances, and microorganisms were used to oxidize and reduce odor substances to decompose them into CO2, H2O and other small molecules of odorless and harmless substances. At present, bacteria such as Thiobacillus denitrificans and Thiobacillus thiooxidans have also been found to be used for biological deodorization. These bacteria can oxidize elemental sulfur or reduced sulfide to obtain the energy required for their own cell growth and metabolism, and use ammonium as a nitrogen source to complete the redox reaction and reduce the generation of odor.

[0006] However, the treatment effect of conventional naturally grown microorganisms has become increasingly difficult to adapt to the increasingly stringent odor-related emission standards at this stage. In some cases, excessive concentrations of sulfur-containing, ammonia-containing organic and inorganic substances also inhibit the deodorization reaction of the original microbial population, resulting in a decrease in the deodorization effect. Therefore, enhanced microbial deodorization strains are urgently needed to enhance the treatment effect of biological deodorization. Summary of the invention

[0007] The object of the present invention is to provide an anaerobic deodorizing strain and its application. To achieve the above object, the present invention adopts the following technical solution.

[0008] In one aspect, the present invention provides a facultative anaerobic deodorizing strain, which is named Bacillus sp. K2F and is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration Committee with a deposit number of CGMCC No. 26416. The deposit address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing. Deposit date: January 6, 2023.

[0009] The facultative anerobic deodorizing strain K2F provided by the present invention belongs to a species of Bacillus sp. In the comparison of gene sequence structure, it was found that it has great differences with all the known microorganisms and is a newly discovered strain.

[0010] The facultative anaerobic deodorizing strain K2F provided by the present invention can survive well under both anoxic and aerobic conditions. It can utilize reduced sulfur and ammonium in sewage or odor, and use nitrate as the final electron acceptor under anoxic conditions and molecular oxygen as the final electron acceptor under aerobic conditions to complete the early treatment or decomposition of odor substances, thereby achieving the removal of odor substances and reducing the amount of odor emission to the outside, showing a good deodorizing effect, but the treatment and degradation effect under anoxic conditions is better than that under aerobic conditions.

[0011] The facultative anaerobic deodorizing strain K2F provided by the present invention is a fast-growing strain. In a culture medium under suitable conditions, the cell density (OD600) can reach as high as 0.4 within 24 hours.

[0012] In another aspect, the present invention provides the use of the above-mentioned facultative anaerobic deodorizing strain for deodorizing.

[0013] Furthermore, the deodorization is an in-situ or ex-situ odor treatment in a sewage treatment process.

[0014] Furthermore, the deodorization is carried out under anoxic conditions. Preferably, the anoxic conditions refer to the dissolved oxygen in the sewage being less than 1 ppm.

[0015] Furthermore, the deodorization is carried out under aerobic conditions. Preferably, the aerobic conditions refer to the dissolved oxygen in the sewage being 1.0-1.5 ppm.

[0016] Furthermore, the bacteria are first cultured in a directed manner and then placed in sewage for deodorization; the process of directed culture is: preparing a salt solution in a culture container: NaCl 0.8-1.2 g / L, MgCl2 0.4-0.6 g / L, KH2PO4 0.15-0.25 g / L, KCl 0.2-0.4 g / L, CaCl2 0.01-0.02 g / L; after the preparation is completed, inoculating the bacteria into the culture container, and then adding ammonium salt 20-40 mmol / L, nitrate 20-40 mmol / L, sulfide 0.15-0.25 mmol / L, butyrate 1-3 mmol / L, propionate 1.5-2.5 mmol / L; sealing the culture container, maintaining the dissolved oxygen in the culture solution at 0.2-0.5 ppm, shaking the culture container, and the culture time is 12-36 hours.

[0017] The present invention has the following beneficial technical effects: the deodorizing strain K2F provided by the present invention can survive well under both anoxic and aerobic conditions, has a good deodorizing effect under anoxic conditions, and also has a certain deodorizing effect under aerobic conditions; it is a fast-growing strain, is easy to expand and culture, is convenient to combine with the existing deodorizing process, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a phylogenetic tree diagram of the K2F strain of the present invention.

[0019] Figure 2 It is the increase rate (%) relative to the original addition amount after adding K2F strain in Example 1 for a period of time.

[0020] Figure 3 This is the degradation characteristic of the K2F strain of the present invention under anaerobic conditions.

[0021] Figure 4 The K2F strain of the present invention has the characteristic of degrading nitrate and ammonium under anaerobic conditions.

[0022] Figure 5 This is the degradation characteristic of the K2F strain of the present invention under aerobic conditions.

[0023] Figure 6 This is a comparison chart of the comprehensive odor removal rate in Example 3. Implementation

[0024] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings of the specification. Obviously, the described implementation is only a part of the implementation of the present invention, not all of the implementations. Based on the implementation of the present invention, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0025] Preparation of instruments and materials: conical flask, various salts required, deionized water, K2F strain, spectrophotometer.

[0026] Prepare salt solution in a conical flask: NaCl 1.0g / L, MgCl2 0.5g / L, KH2PO4 0.2g / L, KCl 0.3g / L, CaCl2 0.015g / L. After preparation, inoculate K2E bacteria into the conical flask, and then add 30mmol / L ammonium salt, 30mmol / L nitrate, 0.2mmol / L sulfide, 2mmol / L butyrate, and 2mmol / L propionate.

[0027] After sealing the conical flask, start shaking and maintain the dissolved oxygen in the conical flask at a low level (0.2~0.5ppm).

[0028] The K2F strain grew rapidly. Its transmittance was tested after 1 day, and its OD value was as high as 0.4, indicating that the K2F strain could grow rapidly in this culture medium.

[0029] The 16S rDNA gene sequence of K2F was sequenced and it was found that its 16S rDNA belongs to the genus Bacillus. The phylogenetic tree of K2F is shown in Figure 1 .

[0030] In order to test the survival adaptability of the K2F strain provided by the present invention, the K2F strain was added to three sewage treatment plants in Heilongjiang, Beijing and Guangdong. It was found that after a period of addition, the K2F strain increased by 0.6 to 3.5 times in the system. The results are as follows: Figure 2 As shown, it is shown that the K2F strain provided by the present invention has a strong survival adaptability. Example 2

[0031] A variety of substances such as lactic acid, formic acid, acetic acid, propionic acid, butyric acid, ammonium, nitrate, volatile fatty acids (VFAs) were selected and prepared at certain concentrations to simulate metabolic substrates, and the degradation characteristics of the deodorizing strain K2E on the metabolic substrates were tested.

[0032] The K2F facultative anaerobic deodorizing Bacillus strain provided by the present invention has a degradation process for all volatile fatty acids except lactic acid under anaerobic conditions. The degradation characteristics are shown in the figure below. Figure 3 In addition, the K2F strain can effectively reduce nitrate to ammonium (DNRA: Dissimilatory Nitrate Reduction to Ammonium, with nitrite as the intermediate product). Ammonia nitrogen first decreases and then increases with the decrease of nitrate. Nitrite is the intermediate product of the DNRA process. The degradation characteristics of ammonium and nitrate are shown in the figure Figure 4shown.

[0033] The K2F facultative anaerobic deodorizing Bacillus strain provided by the present invention has a reduced odor degradation ability under aerobic conditions, which is specifically reflected in that the K2F strain can degrade butyric acid and ammonium; other odorous substances are not effectively removed under aerobic conditions, and the degradation effect under aerobic conditions is greatly inhibited. Figure 5 shown. Example 3

[0034] In a deodorization device of a sewage treatment plant, the K2F facultative anaerobic deodorizing Bacillus strain provided by the present invention and the existing deodorizing strain were added respectively to test the comprehensive removal rate of odor. The test results are as follows: Figure 6 shown.

[0035] It can be seen from the figure that compared with the existing deodorizing strains, the K2F facultative anaerobic deodorizing Bacillus strain provided by the present invention has an increased comprehensive odor removal rate and smaller fluctuations, reflecting good deodorizing performance.

[0036] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. The protection scope of the present invention is defined by the claims and their equivalent technical solutions.

Claims

1. A facultative anaerobic deodorizing strain, characterized in that: The strain was named Bacillus ( Bacillus sp. )K2F, deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number CGMCC No. 26416.

2. The use of the strain for deodorization according to claim 1, wherein the deodorization is in-situ or ex-situ odor treatment in a sewage treatment process, and the deodorization is carried out under anaerobic conditions.

3. The use according to claim 2, characterized in that: The anoxic condition refers to that the dissolved oxygen in the sewage is less than 1 ppm.

4. The use of the strain for deodorization according to claim 1, wherein the deodorization is in-situ or ex-situ odor treatment in a sewage treatment process, and the deodorization is carried out under aerobic conditions.

5. The use according to claim 4, characterized in that: The aerobic condition refers to the dissolved oxygen in the sewage being 1.0-1.5 ppm.

6. The use according to any one of claims 2 to 5, characterized in that: The strain is first cultured in a directed manner, and then placed in sewage for deodorization; the process of directed culture is: a salt solution is prepared in a culture container: NaCl 0.8-1.2 g / L, MgCl2 0.4-0.6 g / L, KH2PO4 0.15-0.25 g / L, KCl 0.2-0.4 g / L, CaCl2 0.01-0.02 g / L; after the preparation is completed, the bacteria are inoculated into the culture container, and then ammonium salt 20-40 mmol / L, nitrate 20-40 mmol / L, sulfide salt 0.15-0.25 mmol / L, butyrate 1-3 mmol / L, propionate 1.5-2.5 mmol / L are added; the culture container is sealed, the dissolved oxygen in the culture solution is maintained at 0.2-0.5 ppm, the culture container is shaken, and the culture time is 12-36 hours.

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