An aerobic deodorizing strain and its application

Abstract

The present invention discloses an aerobic deodorization strain and its application. The strain is named Bacillus sp. K2E and is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration Committee with the deposit number of CGMCC No.26415. Under aerobic conditions, the strain has an obvious degradation trend for all odor substances including VFAs and ammonium, and can be used for in-situ or ex-situ odor treatment of sewage under aerobic conditions; it can still deodorize when there is a high concentration of inhibitory factors in the sewage, and has good adaptability to fluctuations in sewage quality; it is a fast-growing strain, easy to expand and culture, convenient to combine with existing deodorization processes, and has good application prospects.

Description

Technical Field

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

[0002] The odor produced by various sewage treatment systems is one of the main sources of urban odor, and sewage treatment plants are often complained about because of this.

[0003] In view of this situation, an important investment in sewage treatment plants is the odor treatment system. 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.

[0004] 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, many bacteria have been proven to be used for deodorization, such as Thiobacillus denitrificans and Thiobacillus thiooxidans, which can oxidize elemental sulfur or reduced sulfide to obtain the energy needed 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.

[0005] 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, wastewater contains excessively high concentrations of sulfur-containing and ammonia-containing organic matter, as well as some excessively high concentrations of inorganic matter, which will inhibit the deodorization reaction of the original microbial population and lead to a reduction in the deodorization effect.

[0006] There is an urgent need to find new strains of bacteria that can meet the current requirements for odor emissions in sewage treatment and can still deodorize when high concentrations of inhibitory factors (nitrite and / or sulfide) are present in the sewage. Summary of the invention

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

[0008] On the one hand, the present invention provides an aerobic deodorizing strain, which is named Bacillus sp. K2E and is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration Committee with a deposit number of CGMCC No. 26415. The deposit address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Deposit date: January 6, 2023.

[0009] The aerobic deodorizing strain K2E provided by the present invention belongs to a species of Bacillus sp. In the comparison of gene sequence structure, it is found that it is extremely different from all the known microorganisms.

[0010] The aerobic deodorizing strain K2E 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.

[0011] In another aspect, the present invention provides the use of the above-mentioned aerobic deodorizing strain for deodorizing.

[0012] Furthermore, the deodorization is an in-situ or ex-situ odor treatment in a sewage treatment process.

[0013] 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.

[0014] Furthermore, deodorization can still be achieved when there is a high concentration of inhibitory factors in the sewage, wherein the high concentration of inhibitory factors refers to: nitrite reaching a maximum of 15 mmol / L and / or sulfide reaching a maximum of 1.5 mmoL / L.

[0015] 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.

[0016] The present invention has the following beneficial technical effects: the deodorizing strain K2E provided by the present invention has a good deodorizing effect under aerobic conditions; it can still deodorize when there is a high concentration of inhibitory factors in the sewage, and has good adaptability to fluctuations in sewage quality; it is a fast-growing strain, easy to expand and culture, convenient to combine with the existing deodorizing process, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a phylogenetic tree diagram of the K2E strain of the present invention.

[0018] Figure 2 This is the degradation characteristic of the K2E strain of the present invention under aerobic conditions.

[0019] Figure 3 This is the degradation characteristic of the K2E strain of the present invention under anaerobic conditions.

[0020] Figure 4 This is a comparison chart of the comprehensive odor removal rate in Example 3. Implementation

[0021] 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

[0022] Preparation of instruments and materials: conical flask, various salts required, deionized water, K2E strain, spectrophotometer.

[0023] 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.

[0024] After sealing the conical flask, start shaking and maintain the dissolved oxygen in the conical flask at a low level (0.2~0.5ppm).

[0025] The K2E strain grew rapidly. Its transmittance was tested after 24 hours, and its OD value was as high as 0.4, indicating that the K2E strain could grow rapidly in this culture medium.

[0026] The 16S rDNA gene sequence of the above K2E strain was sequenced and it was found that its 16S rDNA belongs to the genus Bacillus. The phylogenetic tree of K2E is shown in Figure 1 . Example 2

[0027] 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.

[0028] The aerobic deodorizing strain K2E provided by the present invention can utilize reduced sulfur and ammonium in sewage or odor under aerobic conditions (dissolved oxygen is 1.0-1.5ppm) and molecular oxygen as the final electron acceptor to pre-treat or decompose odor substances, thereby achieving the removal of odor substances and reducing the amount of odor emission, showing a good deodorizing effect. In the deodorizing process of the aerobic deodorizing strain K2E provided by the present invention, all odor substances including VFAs and ammonium have a significant degradation trend, and the degradation characteristics are shown in the figure below. Figure 2 The decrease in total nitrogen indicates that ammonium is degraded rather than simply absorbed; the decrease in total organic carbon indicates that volatile fatty acids are ultimately degraded in the form of gas (such as CO2).

[0029] The aerobic deodorizing strain K2E provided by the present invention has a degradation characteristic under anaerobic conditions (dissolved oxygen is less than 1 ppm) as shown in the figure below: Figure 3 As shown in the figure, it can be seen that the odor degradation ability of the K2E strain decreased under anaerobic conditions and it was difficult for it to function normally. Specifically, the concentration of odor-producing substances hardly changed; even after the addition of electron donors (nitrates), the concentration of total organic carbon hardly changed. Example 3

[0030] In the deodorization equipment of a sewage treatment plant, the aerobic deodorization strain K2E provided by the present invention and the existing deodorization strain were added to test the comprehensive removal rate of odor. The water quality fluctuated during the test, with the highest nitrite reaching 15mmol / L and the highest sulfide reaching 1.5mmoL / L. The test results are as follows: Figure 4 shown.

[0031] It can be seen from the figure that compared with the existing deodorizing strains, the aerobic deodorizing strain K2E provided by the present invention has an increased comprehensive odor removal rate and smaller fluctuations, reflecting good deodorizing performance.

[0032] 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. An aerobic deodorizing strain, characterized in that: The strain was named Bacillus ( Bacillus sp. )K2E, deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number CGMCC No. 26415.

2. The use of the strain for deodorization according to claim 1, wherein the deodorization is an in-situ or ex-situ odor treatment in a sewage treatment process, and the deodorization is carried out under aerobic conditions, wherein the aerobic conditions refer to a dissolved oxygen content of 1.0 to 1.5 ppm in the sewage.

3. The use according to claim 2, characterized in that: When there are high concentration inhibitory factors in the sewage, deodorization can still be achieved, wherein the high concentration inhibitory factors refer to: nitrite reaching a maximum of 15mmol / L and / or sulfide reaching a maximum of 1.5mmoL / L.

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