A strain of Brucella intermedia LW2 and its application

Abstract

The present invention discloses an application of an intermediate Brucella LW2 in the treatment of nitrogen-sulfur polluted wastewater. The strain is an intermediate Brucella (Brucella intermedia) LW2, which has been preserved in the Guangdong Provincial Microbial Culture Collection Center on November 4, 2021, with a deposit number of GDMCC No.62034. The intermediate Brucella GDMCC62034 strain has a relatively wide range of suitable growth temperature, between 10-50 ° C and still has denitrification and sulfate reduction capabilities under aerobic conditions, and does not release N2O. It can be used for denitrification treatment of nitrogen-containing wastewater, denitrification and desulfurization of nitrogen-containing sulfur wastewater, and can also be used for the removal of nitrogen oxides and sulfur dioxide in flue gas or exhaust gas.

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and more specifically, relates to a strain of Brucella intermedia LW2 having aerobic denitrification and sulfate reduction functions under aerobic conditions, and its application in simultaneous denitrification and desulfurization in wastewater and denitrification and desulfurization in flue gas or exhaust gas. Background Art

[0002] Nitrogen and sulfur are the two main pollutants in wastewater. When discharged into urban water bodies in large quantities, they consume dissolved oxygen in the water under the action of microorganisms, causing hypoxia or anaerobic environment in the water, and eventually causing the water to become black and smelly. The traditional technology for removing nitrogen and sulfate is to treat them separately. Biological denitrification technology mainly includes denitrification, anaerobic ammonia oxidation, etc., while biological desulfurization technology mainly uses sulfate-reducing bacteria to convert sulfate into sulfide or H2S through biological reduction and then generate elemental sulfur through biological oxidation. However, the process is complicated and unstable, which increases the burden of subsequent treatment. Therefore, how to achieve synchronous denitrification and desulfurization is a difficult problem facing current wastewater treatment.

[0003] In addition, although the total amount of waste gas emissions in my country has been effectively controlled in recent years, NOx and SO2 are still the main components of atmospheric pollutants in my country. Since NOx and SO2 can produce acid rain, etc., which have serious adverse effects on human health and the ecological environment, the control of NOx and SO2 is still urgent. Biofiltration denitrification is a method of efficiently removing NOx from flue gas or waste gas by forming an aerobic denitrifying microbial community, and can operate stably in a flue gas or waste gas environment for a long time. Flue gas desulfurization usually adopts a wet desulfurization process. After the flue gas enters the desulfurization equipment, it will be absorbed by the liquid, but it is easy to cause pollutants in the tail liquid. And if the tail liquid is discharged directly, it will pollute the environment.

[0004] Therefore, there is an urgent need to treat sulfur-containing and nitrogen-containing wastewater in my country. The denitrification desulfurization process can effectively remove sulfur-containing and nitrogen-containing pollutants in wastewater, and recover elemental sulfur from the wastewater. However, there are many types of functional microorganisms and complex metabolism in the denitrification desulfurization reactor, which leads to low and unstable elemental sulfur generation rate. The use of bioaugmentation technology can solve these problems efficiently and at low cost. Summary of the invention

[0005] The purpose of the present invention is to provide a strain having high-efficiency aerobic denitrification and sulfate reduction performance under medium and low temperature conditions and its use.

[0006] The present invention provides a strain of Brucella intermedia LW2, which was preserved in the Guangdong Provincial Microbiological Culture Collection Center on November 4, 2021, with the preservation number GDMCC No: 62034, and the preservation address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0007] The present invention has isolated a strain with aerobic denitrification and denitrification and sulfate reduction performance from a biofilter device for treating flue gas with simultaneous denitrification and desulfurization. After morphological, physiological and biochemical, and molecular biological identification, the strain belongs to Brucella intermedia and is named Brucella intermedia LW2. The 16S rRNA gene sequence obtained by sequencing the strain contains 1316 bases. The nucleotide homology comparison with the registered sequence in Genebank using the Blast program shows that the 16S rRNA gene sequence of the strain has a homology of 99.92% with that of Brucella intermedia. The 16S rRNA phylogenetic tree of the strain is as follows: Figure 3 shown.

[0008] The purpose of the present invention is mainly achieved through the following technical means:

[0009] A strain of Brucella intermedia LW2 is deposited in the Guangdong Provincial Microbiological Culture Collection Center with the accession number GDMCC No: 62034. The storage address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou. The storage time is November 4, 2021.

[0010] Preferably, the Brucella intermedia LW2 is used in wastewater denitrification and desulfurization treatment.

[0011] Preferably, the wastewater is nitrogen- and sulfur-containing wastewater at a temperature of 10-50°C.

[0012] Preferably, the Brucella intermedia LW2 is used in aerobic denitrification, denitrification and desulfurization treatment of flue gas or waste gas.

[0013] Preferably, the aerobic denitrification and desulfurization treatment temperature of the flue gas or waste gas is 10-50°C.

[0014] Preferably, the oxygen content in the flue gas or waste gas is 3%-8%.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] (1) After the strain Brucella intermedia LW2 of the present invention is cultured in a basic salt medium with nitrate as the only nitrogen source for 24 hours, the degradation effect of nitrate is 100%, and there is no release of greenhouse gas nitrous oxide. At the same time, the bacteria can also degrade sulfate into sulfide, thereby achieving the purpose of simultaneous denitrification and desulfurization. In addition, the strain can also tolerate higher concentrations of nitrate and sulfate.

[0017] (2) The Brucella intermedia LW2 can achieve aerobic denitrification under aerobic conditions, and can be inoculated into aerobic nitrification sludge to achieve simultaneous nitrification and denitrification of nitrogen-containing wastewater, and is suitable for denitrification treatment of various nitrogen-containing wastewaters. More importantly, the bacteria can also achieve denitrification and sulfate reduction under the conditions of NO as a nitrogen source and a certain amount of SO2, and ultimately reduce NO to N2 and convert SO2 into sulfide, thereby achieving simultaneous denitrification and desulfurization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the colony morphology of Brucella intermedia LW2.

[0019] Figure 2 This is a microscopic morphology of Brucella intermedia LW2.

[0020] Figure 3 This is the 16S rRNA phylogenetic tree of Brucella intermedia LW2.

[0021] Figure 4 This is the simultaneous degradation curve of nitrate and sulfate by Brucella intermedia LW2.

[0022] Figure 5 This is a diagram of the simultaneous denitrification and desulfurization of NOx and SO2 in flue gas by Brucella intermedia LW2. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below in conjunction with specific examples, but the implementation mode of the present invention is not limited to the following examples.

[0024] The aerobic denitrifying bacteria provided in the present invention are Brucella intermedia LW2, whose deposit number is GDMCC No:62034.

[0025] Example 1 Screening, Isolation and Performance Identification of Strain

[0026] 1. Screening and isolation of strains

[0027] In this study, 1 mL of bacterial solution was taken from a long-term biofiltration reactor for dilution and plating. After 24 hours, a single colony was selected and purified by streaking three times. The isolated and purified strains were inoculated into triangular bottles containing 120 mL of inorganic salt culture solution (with nitrate and sulfate as the only nitrogen and sulfur sources), and the bottle mouths were wrapped with sterile filter membranes and placed in a shaking incubator. The specific parameters are as follows: temperature 40°C, speed 120r / min, and culture time 24h. The cultured bacterial solution was taken to detect the concentration of nitrate nitrogen and sulfate, and the removal rate of nitrate nitrogen and sulfate by the strain was investigated. A single strain with a denitrification efficiency of 100% and sulfate reduction ability was selected, namely strain LW2.

[0028] 2. Identification of strains

[0029] 2.1 Morphology and culture characteristics

[0030] The strain LW2 was cultured on NA (nutrient agar) plates at 30°C for 48 hours. The colonies were round, convex, smooth, with neat edges and milky white. The colony morphology is shown in the figure. Figure 1 .

[0031] 2.2 Microscopic morphological characteristics

[0032] Microscopic morphology shows that it is a Gram-negative coccobacillus or short rod. Figure 2 .

[0033] 2.3 Physiological and biochemical characteristics

[0034]

[0035]

[0036] (“+” indicates a positive reaction, “-” indicates a negative reaction)

[0037] Example 2 Molecular Biology Identification Results

[0038] DNA sequencing revealed that the 16S rRNA gene sequence of the strain was 1316 bp, and the sequence information is shown in the sequence table. The nucleotide homology was compared with the sequences registered in Genebank using the Blast program, and the homology of the 16S rRNA gene sequence of the strain to that of Brucella intermedia reached 99.92%. The phylogenetic tree of the 16S rRNA gene of the strain is shown in Figure 3Based on the above identification results, the strain was named Brucella intermedia LW2 and was deposited in Guangdong Microbiological Culture Collection Center on November 4, 2021, with the deposit number GDMCC No: 62034, and the deposit address is: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0039] Example 3 Brucella intermedia LW2 for biological denitrification of wastewater

[0040] Transfer the culture solution expanded in liquid agar medium into 150 mL of 500 mg / L NO3 - In an inorganic salt culture medium (K2HPO4 (0.5), KH2PO4 (1), MgSO4 (0.246), CaCl2 (0.0111), FeSO4 (0.005), glucose (2, unit (g / L)), cultured at 40°C and 120r / min for 24h, the degradation rate of nitrate nitrogen was 100%. The bacteria degraded nitrate into clean nitrogen without secondary pollution, namely the release of N2O.

[0041] Example 4 Brucella intermedia LW2 for biological denitrification and desulfurization of wastewater

[0042] Transfer the culture solution expanded in liquid agar medium into 150 mL of 500 mg / L NO3 - and 200mg / LSO4 2- In the sulfate inorganic salt medium (K2HPO4 (0.5), KH2PO4 (1), MgSO4 (0.246), CaCl2 (0.0111), FeSO4 (0.005), glucose (2, unit (g / L)), cultured at 40℃, 120r / min for 24h, the degradation rate of nitrate nitrogen was 100%, and the reduction rate of sulfate could reach 98%. The degradation curve is shown in Figure 4 shown.

[0043] Example 5 Brucella intermedia LW2 is used for biological simultaneous denitrification and desulfurization in flue gas or waste gas

[0044] Brucella intermedia LW2 was used to form biofilm on the biofilter (the concentration of NOx and SO2 in the simulated flue gas was 100-1000 mg / m 3 and 100-500 mg / m 3, oxygen content 3-8%), after two weeks of biofilm operation, the NOx removal rate was stable at more than 90% without N2O release, and the SO2 removal rate was stable at around 99%. Figure 5 shown.

[0045] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

[0046] 16S rRNA nucleotide sequence of Brucella intermedia LW2:

[0047]

Claims

1. A strain of Brucella intermedia LW2, characterized in that: It is deposited in Guangdong Provincial Microbiological Culture Collection Center with the accession number GDMCC No: 62034. The storage address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou. The storage time is November 4, 2021.

2. Use of the Brucella intermedia LW2 described in claim 1 in wastewater denitrification and desulfurization treatment.

3. The use according to claim 2, characterized in that: The wastewater is nitrogen- and sulfur-containing wastewater at a temperature of 10-50°C.

4. Use of the Brucella intermedia LW2 described in claim 1 in aerobic denitrification, denitrification and desulfurization treatment of flue gas or waste gas.

5. The use according to claim 4, characterized in that: The temperature of the aerobic denitrification, denitrification and desulfurization treatment of flue gas or waste gas is 10-50°C.

6. The use according to claim 4 or 5, characterized in that: The oxygen content in the flue gas or waste gas is 3%-8%.

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