CN113913329A

CN113913329A - High-salt-tolerance COD (chemical oxygen demand) reducing strain, acquisition method and application

Info

Publication number: CN113913329A
Application number: CN202111203712.XA
Authority: CN
Inventors: 李再兴; 张婉玉; 白玉玮; 安鸿雪; 宁静; 秦学; 薛非; 王冰然
Original assignee: Shijiazhuang High Tech Industrial Development Zone Water Supply And Drainage Co; Hebei University of Science and Technology
Current assignee: Shijiazhuang High Tech Industrial Development Zone Water Supply And Drainage Co; Hebei University of Science and Technology
Priority date: 2021-10-15
Filing date: 2021-10-15
Publication date: 2022-01-11
Anticipated expiration: 2041-10-15
Also published as: CN113913329B

Abstract

The invention relates to a high-salt-tolerance COD (chemical oxygen demand) reducing strain, which is a Yixing Groniella (Mangrovibacter yixingensis) strain named as Mangrovibacter yixingensis T3, and is preserved in China general microbiological culture Collection center (CGMCC) at 7-30 th 2021 with the preservation number of CGMCC No. 22992. The strain can survive in pharmaceutical wastewater with high salt content (less than or equal to 200g/L) and high COD (10000mg/L) and shows good biological activity, organic waste in the wastewater can be consumed, and experiments prove that the COD degradation rate of the high-salt wastewater in 48h reaches more than 89%, so the strain can be used as an active strain for treating the pharmaceutical wastewater by a biological method to reduce the COD of the wastewater and improve the efficiency of treating the pharmaceutical wastewater by an activated sludge method. In addition, the invention also relates to an acquisition method and application of the strain.

Description

High-salt-tolerance COD (chemical oxygen demand) reducing strain, acquisition method and application

Technical Field

The invention relates to the technical field of application strains, in particular to a high-salt-tolerance COD (chemical oxygen demand) reducing strain, an acquisition method and application.

Background

The industrial output value of the pharmaceutical industry in China accounts for 2.35 percent of the total industrial value in China, the drug export amount reaches more than 60 percent, a large amount of pharmaceutical wastewater is generated while good economic benefit is obtained, the discharge amount of the pharmaceutical wastewater accounts for 2 percent of the discharge amount of the industrial wastewater, the environmental pollution is caused, and the pharmaceutical wastewater becomes one of the factors restricting the industry development.

The pharmaceutical wastewater is mainly derived from wastewater generated by fermentation, extraction, filtration, ion exchange and pharmaceutical equipment cleaning in the drug research and development and production processes, and has the characteristics of high organic matter content, high toxicity, high salt content and poor biodegradability due to the fact that the content of pollutants in the wastewater is greatly different due to different pharmaceutical raw materials and production modes. The existence of high organic matter of high salt can corrode the operation pipeline and the equipment of enterprise on the one hand, is unfavorable for enterprise's safety in production and development economic benefits, has serious hidden danger of revealing, and on the other hand has weakened the treatment effect of traditional biological method to waste water, leads to the difficult discharge to reach standard of effluent.

At present, the methods for treating high-salt organic pharmaceutical wastewater mainly comprise a Fenton catalytic oxidation method, a double-membrane method, a forward osmosis method and the like, but the methods still have the problems of low treatment efficiency, high operation cost and the like; the biological method has low cost, but microorganisms are difficult to survive in high-salt environment, so that the treatment effect of the activated sludge method is poor. By culturing and domesticating the salt-tolerant strains, the survival capability and activity in a high-salt environment are improved, and the treatment effect of the biological method on the high-salt organic pharmaceutical wastewater can be improved.

At present, some scholars screen and domesticate salt-tolerant microorganisms and apply the salt-tolerant microorganisms to degrade high-salt organic wastewater. For example, Bertrand J C and the like utilize halotolerant bacteria to treat wastewater with salt content of 6-20%, and the removal rate of COD is stabilized to be more than 70%. Ginger and phoenix et al utilize a halotolerant bacteria enhanced MBR process of Bacillus cereus to treat the high salt-containing leachate, and the removal rate of COD reaches 71%. However, the pharmaceutical wastewater has extremely complex components, and contains part or all of toxic benzene, aldehyde, ester, ether, methanol, ethanol, formic acid, protein, phosphate and the like besides high COD and high chloride ion concentration, and halides and various antibiotics have great inhibition and toxic effects on microorganisms, so that ordinary microorganisms cannot grow normally; the high salinity of the waste water can cause the over-high osmotic pressure inside and outside cells to cause the death of microorganisms or inhibit the enzyme activity to influence the growth and metabolism. Therefore, the strain which is suitable for being applied to a high-salt pharmaceutical wastewater system to reduce the COD of the wastewater still has certain difficulty in actual separation and screening. Furthermore, it is understood that no reports relating to the high salt-tolerant Yixing Manger rod strain are known in the art.

Disclosure of Invention

Technical problem to be solved

In view of the above disadvantages and shortcomings of the prior art, the present invention provides a high salt-tolerance COD-reducing strain, which can survive in pharmaceutical wastewater with high salt content and high COD, exhibit excellent biological activity, and consume organic waste in the wastewater, so that the strain can be used as an active strain for biological treatment of pharmaceutical wastewater to reduce COD of the wastewater and improve the efficiency of the activated sludge process for treatment of pharmaceutical wastewater. In addition, the invention also relates to an acquisition method and application of the strain.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

in a first aspect, the invention provides a high-salt-tolerance COD-reducing bacterial strain, which is a Bacillus meretricus (Magrovibacter yixingensis) and is named as Magrovibacter yixingensis T3, and the strain is preserved in China general microbiological culture Collection center (CGMCC) at 30 th 2021, with the preservation number of CGMCC No.22992 and the preservation address of No. 3 Hosierra No. 1 of Beijing Korean Yang district.

The strain is proved to be capable of normally surviving, growing, metabolizing and reproducing in pharmaceutical wastewater containing high-concentration sodium chloride, and has the capacity of degrading high-concentration COD; the COD concentration of the pharmaceutical wastewater is more than 10000mg/L, preferably 11300-15950.5mg/L, and the concentration of sodium chloride is less than or equal to 200 g/L.

In a second aspect, the invention provides a method for obtaining a high-salt-tolerance COD-reducing bacterial strain, which comprises the following steps:

s1 domestication of halotolerant flora

Collecting activated sludge from the water inlet of a secondary sedimentation tank for sewage treatment of a certain pharmaceutical factory in Shijiazhuang, and directionally domesticating sodium chloride-resistant flora by adopting a method of gradually increasing the concentration of sodium chloride;

s2 screening for viable bacteria

After acclimation for a period of time, standing the sludge, taking a certain amount of supernatant, performing gradient dilution to obtain a series of gradient diluents, respectively coating the gradient diluents in a broth culture medium plate, performing constant-temperature inverted culture at (28-35 ℃) until obvious bacterial colonies are generated on the broth culture medium plate, and recording different bacterial colony forms;

s3, purification of single colony

Picking single colonies with different shapes, sizes and colors from a broth culture medium plate with a proper gradient concentration, inoculating the single colonies into the broth culture medium plate, and carrying out streaking culture for multiple times until purified single colonies are obtained;

s4 screening of halotolerant bacteria

Respectively preparing selective culture media with gradient sodium chloride concentration, preparing a purified single colony into bacterial suspension, inoculating the bacterial suspension into the selective culture media (inoculating the bacterial suspension with the thallus mass concentration of 1.8-2.2% d, preferably the concentration of 2.0%), culturing for 3-4 days in a shaking table at constant temperature, sampling at preset time intervals to measure COD degradation conditions, and screening out the high-salt-degradation-resistant COD strain.

The screened high-salt-resistant COD-reducing strain is coated on a broth culture medium plate and is inversely cultured for 3-7 days at 37 +/-0.5 ℃ in an incubator, the morphological characteristics of the bacterial colony are observed, the morphological characteristics and the physicochemical properties of the bacterial colony have certain difference with those of reported Magrovibacter (gram negative), and the bacterial colony is gram positive and possibly is a new bacterial strain of the genus of the Magrovibacter. The DNA of the high-salt-resistant COD-reducing strain is further extracted to carry out 16S rDNA sequence determination, the strain is Yixing Gracilaria (Mangrobacter) named as Mangrobacter T3, and is preserved in China general microbiological culture Collection center (CGMCC) at 30 months 7 in 2021 with the preservation number of CGMCC No. 22992. The strain Mangrobacter yixinensis T3 and other homologous bacteria with high similarity are used for constructing a phylogenetic tree by MEGA7.0 software, and the figure is shown in figure 3. The selected strains were stored in a refrigerator at-80 ℃ using the glycerolysis method.

According to a preferred embodiment of the present invention, in S2-S3, the composition of the broth is: 2.8-3.2g/L beef extract, 9.5-10.5g/L peptone, 9.5-10.5g/L sodium chloride and 18-22g/L agar, and sterilizing to obtain broth culture medium with pH of 7.0-8.0. Preferably, the broth culture is: 3g/L beef extract, 10g/L peptone, 10g/L sodium chloride and 20g/L agar, and sterilizing to obtain the beef extract with the pH value of 7.0-8.0.

According to a preferred embodiment of the present invention, in S4, the selective medium comprises: 0.8-1.2g/L (preferably 0.9-1.0g/L) of glucose, 0.15-0.16g/L of ammonium chloride, 0.03-0.04g/L of monopotassium phosphate, 0.046-0.0495g/L of magnesium sulfate, 0.003-0.0035g/L of ferrous sulfate and 10-50g/L of sodium chloride; the solvent is deionized water.

S4, the conditions for constant temperature culture in a shaking table are as follows: 28-35 deg.C (preferably 30 deg.C), 180-220r/min, and shake culturing for 70-80 h.

In a third aspect, the invention provides an application of a high-salt-resistant COD-reducing strain, wherein the strain is a Magnovibacteriixingensis T3 strain, and is used for being inoculated into a biochemical treatment system to treat organic wastewater containing high-concentration sodium chloride.

Preferably, the method of applying comprises:

step 1: carrying out amplification culture on the strains to obtain a bacterial liquid subjected to amplification culture;

extracting single colony in liquid basic culture medium, shake culturing at 28-32 deg.C (preferably 30 deg.C) and 110-4500 rpm (preferably 4000 rpm) for 20-30h (preferably 24h)⁾Centrifuging for 10min, washing thallus cells with purified water to prepare a bacterial suspension, transferring the bacterial suspension to a whole culture medium at an inoculation concentration of 4.5-5.5%, and performing shake cultivation for 20-30h (preferably 24h) at 28-32 ℃ and 200 r/min;

step 2: inoculating the bacterial liquid into the biochemical treatment system of the high-salinity wastewater at the inoculation concentration of 1.8-2.2% (preferably 2%).

The liquid basal medium contains: 2.8-3.5g/L beef extract, 8-12g/L peptone and 20-40g/L, pH 7.0.0-8.0 g sodium chloride, and sterilizing.

The whole culture medium contains: 14-16g/L (preferably 15g/L) of peptone, 6.5-8.5g/L (preferably 7.5g/L) of yeast powder, 16.5-18.5g/L (preferably 17.9g/L) of disodium hydrogen phosphate dodecahydrate, 6-7.5g/L (preferably 6.8g/L) of potassium dihydrogen phosphate, 3.5-4.5g/L (preferably 4.0g/L) of ammonium sulfate, 0.80-0.92g/L (preferably 0.87g/L) of anhydrous magnesium sulfate, 4-6g/L (preferably 5g/L) of glucose, 10-15g/L (preferably 12g/L) of glycerol, 20-40g/L (preferably 30g/L) of sodium chloride, and pH7.0-8.0, and is prepared by sterilization.

Preferably, the COD concentration of the high-salinity wastewater is more than 10000mg/L, preferably 11300-15950.5mg/L, and the concentration of sodium chloride is less than or equal to 200 g/L.

Experimental examples prove that the highest removal rate of the strain to COD in the high-salinity wastewater can reach more than 89.23% after 48 hours, and the removal rate of COD in the high-salinity wastewater reaches 95.56% after 72 hours.

In the present application, if the inoculation is carried out with a cell, the inoculation concentration refers to the mass concentration of the cell in the inoculation medium; when inoculated with a bacterial liquid or a bacterial suspension, the volume concentration of the bacterial liquid or bacterial suspension is referred to, and when inoculated with 5% of the bacterial liquid, the volume concentration means that 5mL of the bacterial liquid corresponds to (100-5) mL of the culture medium or wastewater to be treated.

(III) advantageous effects

The main technical effects of the invention are as follows:

activated sludge in a secondary sedimentation tank for wastewater treatment in a pharmaceutical factory is acclimated by high-concentration sodium chloride, then the sludge is kept stand to extract supernatant, the supernatant is cultured in a flat plate after being absorbed to obtain bacterial colonies with different forms, a single bacterial colony is selected to carry out flat plate scribing purification, and a strain of high-salt-resistance Yixing Carlonicus (mangrovebacter yixiensis) is obtained, so the strain is named as mangrovebacter yixiensis T3, can tolerate nondegradable wastewater with sodium chloride concentration of more than 200g/L, COD concentration of 10000mg/L, and can reach more than 89% of COD removal rate in the wastewater, so the strain can be inoculated into a wastewater biochemical reactor in the pharmaceutical factory to degrade the high-salt wastewater, effectively improve the removal effect of organic matters by a traditional activated sludge method, and has controllable cost.

The invention provides a strain source for the biochemical treatment of the high-salt pharmaceutical wastewater, improves the biochemical treatment effect and effectively removes the COD value of the wastewater. The strain can still be rapidly propagated in a high-salt environment, and the debugging time of a biochemical process can be effectively shortened.

Experiments prove that the strain has stronger growth capacity in a high-concentration sodium chloride (the maximum concentration of the sodium chloride is 200g/L), simultaneously shows high-efficiency capacity of degrading organic pollutants in wastewater (the degradation rate is 95.56% in 72 hours when the COD of inlet water reaches 15950.5 mg/L), and has high salt tolerance and high COD degradation performance. The logarithmic growth phase and the stationary phase of the strain are longer (21-96h), which is beneficial to the rapid consumption of various organic pollutants.

The screened strain Mangrobacter yixingensis T3 can survive in acidic wastewater containing methanol, acetic acid, formic acid, phosphate and other substances, provides an efficient bacteria source for degrading high-chloride-ion and high-COD wastewater of pharmaceutical factories, widens the functional application of the Yixing Carnobacterium sp, and has strong practical value.

Drawings

FIG. 1 shows the colony morphology of the screened strain, Mangrovibactyxingensis T3.

FIG. 2 is an electron micrograph of a selected strain, Mangrobacter yixingensis T3.

FIG. 3 is a phylogenetic tree of the strains selected by the present invention.

FIG. 4 is a graph showing the growth of the selected strains of the present invention in liquid media containing different concentrations of NaCl (corresponding to example 4).

FIG. 5 is a graph showing the degradation curve of the selected strains of the present invention at a higher sodium chloride concentration (200g/L) for COD pharmaceutical wastewater (corresponding to example 5).

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

Example 1

This example is strain acclimatization and screening, the method of which is as follows:

the first step is as follows: directional domestication of halotolerant bacteria

Activated sludge is collected from the water inlet of a secondary sedimentation tank for sewage treatment of a certain pharmaceutical factory in Shijiazhuang, and a method for gradually increasing the concentration of sodium chloride is adopted to directionally domesticate sodium chloride-resistant flora. The pharmaceutical factory sewage comprises antibiotic industrial wastewater, synthetic drug production wastewater, Chinese patent drug production wastewater, washing water and washing wastewater in the production process of various preparations. The organic pollution is serious, the COD content of the comprehensive wastewater can reach 8000-10000mg/L, and the comprehensive wastewater contains substances such as methanol, ethanol, formic acid, protein, phosphate and the like, and is acidic.

(1) And (3) putting the activated sludge into a shake flask, adjusting the pH value to 7-8, and controlling the dissolved oxygen to 3-5 mg/L.

(2) With 4 days as a cycle, the salt content (10g/L, 20g/L, 30g/L, 40g/L, 50g/L) is gradually increased

The second step is that: screening for viable bacteria

After acclimation for a period of time, standing the sludge for 20min, taking 10mL of supernatant, sucking 1.0mL of supernatant into a test tube with 9mL of water, performing gradient dilution (10 times, 20 times, 50 times and 100 times) to obtain a series of gradient diluents, respectively coating the gradient diluents into a broth culture medium plate, marking with a marker pen, performing inverted culture at a constant temperature of 30 ℃ until obvious bacterial colonies are generated on the broth culture medium plate, and recording characteristics such as different bacterial colony forms and bacterial colors.

The broth medium consisted of: 3g/L beef extract, 10g/L peptone, 10g/L sodium chloride and 20g/L agar, and sterilizing to obtain the beef extract with the pH value of 7.0-8.0.

Third, purifying the single colony

Picking single colonies with different shapes, sizes and colors from a broth culture medium plate with proper (the plate with thinner single colony distribution is easy to pick the single colonies) gradient concentration, inoculating the single colonies into the broth culture medium plate, and carrying out streaking culture for 3 times (the culture condition is shown as the second step) until the purified single colonies are obtained.

Fourthly, screening of halotolerant bacteria

Respectively preparing selective culture media (10g/L, 20g/L, 30g/L, 40g/L and 50g/L) with gradient sodium chloride concentration, preparing purified single colonies into bacterial suspensions, inoculating the bacterial suspensions into the selective culture media (liquid culture media) at an inoculation concentration of 2.0% (the mass concentration of the bacterial strains in the culture media is 2%), culturing for 4 days at constant temperature in a shaking table, sampling at preset time intervals to detect COD degradation conditions, and screening out the high-salt degradation resistant COD bacterial strains.

Selecting the components of a culture medium: glucose 0.94g, NH₄Cl 0.153g，KH₂PO₄0.035g， MgSO₄·7H₂O 0.1g，FeSO₄·7H₂Adding distilled water to a constant volume of 1L, wherein the volume is 0.006g of O and 30-150g of NaCl, and adjusting the pH to 7.0-7.5.

Preparing the purified single bacterial colony into bacterial suspension, and inoculating the bacterial suspension into a selective basal culture medium. Shaking culture is carried out for 72h at the conditions of 30 ℃ and 200rpm of a shaking table; sampling every 12h to determine the COD value, and screening out the strain which can tolerate high salt and has the best effect of degrading the COD of the wastewater.

The fifth step: identification of halotolerant bacteria

Inoculating the screened strain which can tolerate high salt and degrade the COD in the wastewater to a broth culture medium plate, inverting the broth culture medium plate, and culturing at 30 ℃ for 24 hours to obtain a single colony. As shown in FIG. 1, the colony morphology was regular, wet, and milky oval.

Further, the shape of the colonies was observed by a microscope after gram-positive staining, and as shown in FIG. 2, the cells were white silkworm cocoon-shaped (oval rod-shaped), approximately 2307.60 μm in length, and smooth at both ends. The results of physical and chemical property experiments show that: the methyl red test is positive, the V-P test is negative, and the facultative aerobe is obtained. The optimum growth pH value is 7.0-8.0.

Further extracting the genomic DNA of the selected strain. After PCR amplification using 16S rDNA universal primers, agarose gel electrophoresis detection was performed to confirm the PCR amplified fragment. The sample was sent for 16S rDNA sequencing. The determined sequence has the highest homology with the Mangrobacter and the similarity reaches more than 95 percent, but the morphological characteristics and the physicochemical properties of the strain have certain difference with the reported Yixing Mangrobacter, the strain is gram positive and possibly is a new strain of the Mangrobacter genus, so the new strain is identified as the Mangrobacter yixingensis strain T3 and is preserved in China general microbiological culture Collection center (CGMCC) at 30 days 2021 and 7, and the preservation number is CGMCC No. 22992. A phylogenetic tree was constructed from the Mangrobacter yixingensis T3 and several other homologous bacteria with high similarity using MEGA7.0 software as shown in FIG. 3. There is no article or report on the ability of the genus Yixing Gerolo to degrade high concentration COD in high concentration sodium chloride wastewater by referring to the relevant data. The screened Mangrobacter yixingensis T3 was then made into glycerol cryopreservation tubes and stored at-80 ℃.

Example 2

In this example, the capability of the Bacillus mangroovibacter Mangroovibacter T3 in degrading the organic substances in the high-salt pharmaceutical wastewater is determined:

the quality of high-salt pharmaceutical wastewater of a pharmaceutical factory in Shijiazhuang is as follows: the COD of the inlet water is 11300.61mg/L, pH is 7.43, the SS is 205.04mg/L, the TN is 1120mg/L, the content of chloride ions is higher and is 22649 mg/L, and the biodegradability of the water quality is poor.

The application process is as follows:

in the step 1, the strain of the Magnovibacteriixingensis T3 is subjected to amplification culture to obtain a bacterial solution subjected to amplification culture.

Extracting single colony in liquid basic culture medium, shake culturing at 30 deg.C and 120rpm for 24 hr at 4000rpm⁾Centrifuging for 10min, washing thallus cells with purified water to prepare bacterial suspension (OD value is 1.20), transferring the bacterial suspension to a whole culture medium at an inoculation concentration of 5%, and performing shake cultivation at 30 ℃ and 200r/min for 24h (OD value is 2.17).

The liquid basal medium contains: 3g/L beef extract, 10g/L peptone, 30g/L, pH 7.0.0 sodium chloride and distilled water, and sterilizing.

The whole culture medium contains: 15g/L of peptone, 7.5g/L of yeast powder, 17.9g/L of disodium hydrogen phosphate dodecahydrate, 6.8g/L of monopotassium phosphate, 4.0g/L of ammonium sulfate, 0.87g/L of anhydrous magnesium sulfate, 5g/L of glucose, 12g/L of glycerol, 30g/L of sodium chloride, pH7.0, distilled water and sterilizing.

And step 2, adding the high-salinity organic wastewater to be treated into a 1000mL conical flask to a scale mark, inoculating the bacterial liquid obtained in the step 1 into the conical flask according to the volume ratio of 2%, controlling the condition temperature to be 30 ℃, performing shake culture in an incubator at the rotating speed of 120rpm, and sampling every 12 hours to measure the COD value of the high-salinity organic wastewater.

Degradation experiment results: the COD value of the initial water sample is 11300.61mg/L, the COD value after 48 hours is 689.34mg/L, and the removal rate of the COD is 93.9 percent.

Example 3

the quality of high-salt pharmaceutical wastewater of a pharmaceutical factory in Shijiazhuang is as follows: the COD of the inlet water is 15950.50mg/L, pH is 8.31, the SS is 198.69mg/L, the content of chloride ions is higher and is 21160mg/L, and the biodegradability of the water quality is poor.

The treatment process is as follows:

adding the high-salinity wastewater of the pharmaceutical factory into a biochemical reactor, adjusting the pH value to 7-8, starting an aeration pump, adjusting the air flow, and controlling the dissolved oxygen to 3-5 mg/L. The bacterial liquid obtained by amplification culture in example 2 is inoculated into a biochemical reactor at an inoculation concentration of 2% (98 mL of wastewater per 2 mL), high-salinity wastewater in a pharmaceutical factory is treated, COD is measured once every 24h, and the detection is continuously carried out for 4 days.

Degradation experiment results: the initial COD was 15950.50 mg/L. At 48h, the COD removal rate was 89.23%. And at 72h, the COD removal rate reaches 95.56 percent.

Example 4

This example is a test of the tolerance, growth curve of the Bacillus mangroovibacter Mannheixiansis T3 in liquid medium at higher NaCl concentration.

Liquid medium composition: 3g/L beef extract, 10g/L peptone, 50-200g/L sodium chloride (50g/L, 150g/L, 200g/L), pH7.0, and distilled water.

As shown in FIG. 4, the strain can still rapidly propagate in a liquid culture medium with the concentration of sodium chloride of 200/L (the delay period is short (0-21h), the logarithmic growth period and the stationary period are long (21-96h), and the debugging time of the biochemical process can be effectively shortened.

Example 5

This example is a test of the capacity of the Bacillus mangrovibacter Mannovibacter T3 to degrade organic substances in wastewater at higher sodium chloride concentrations:

waste water quality of a certain pharmaceutical factory in Shijiazhuang: the COD of the inlet water is 12130.60mg/L, pH is 7.43, the SS is 205.04mg/L, and the salt content is 200 g/L.

The treatment process is as follows:

adding the high-salinity wastewater of the pharmaceutical factory into a biochemical reactor, adjusting the pH value to 7-8, starting an aeration pump, adjusting the air flow, and controlling the dissolved oxygen to 3-5 mg/L. The bacterial liquid obtained by amplification culture in example 2 is inoculated into a biochemical reactor at an inoculation concentration of 2% (98 mL of wastewater per 2 mL), high-salinity wastewater in a pharmaceutical factory is treated, COD is measured once every 24h, and the detection is continuously carried out for 7 days.

As shown in fig. 5, the results of the degradation experiment: the initial COD was 12130.60 mg/L. At the time of 3d, the COD removal rate was 47.83%. At the 7d, the COD removal rate reached 75.49%.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The high-salt-tolerance COD-reducing bacterial strain is a Yixing Grosler bacillus (Mangrobacter yixingensis) which is named as Mangrobacter yixingensis T3 and is preserved in China general microbiological culture Collection center at 30 months at 2021, with the preservation number of CGMCC No.22992 and the preservation address of No. 3 Hosiebola No. 1 of the Chao Yang district in Beijing.

2. The high-salt-tolerance COD-reducing strain according to claim 1, which normally survives, grows, metabolizes and propagates in pharmaceutical wastewater containing high-concentration sodium chloride, and has the capability of degrading high-concentration COD; the COD concentration of the pharmaceutical wastewater is more than 10000mg/L, and the concentration of sodium chloride is less than or equal to 200 g/L.

3. The method for obtaining the high-salt-tolerance COD-reducing strain according to claim 1, comprising the following steps:

s1 domestication of halotolerant flora

s2 screening for viable bacteria

After acclimation for a period of time, standing the sludge, taking a certain amount of supernatant, performing gradient dilution to obtain a series of gradient diluents, respectively coating the gradient diluents in a broth culture medium plate, performing constant-temperature inverted culture until obvious bacterial colonies are generated on the broth culture medium plate, and recording different bacterial colony forms;

s3, purification of single colony

s4 screening of halotolerant bacteria

Respectively preparing selective culture media with gradient sodium chloride concentration, preparing a purified single colony into bacterial suspension, inoculating the bacterial suspension into the selective culture media, culturing for 3-4 days at constant temperature in a shaking table, sampling at preset time intervals to measure COD degradation conditions, and screening out high-salt-degradation-resistant COD strains;

DNA of the high-salt-resistant COD-reducing strain is extracted and subjected to 16S rDNA sequence determination, and the strain is identified as the Yixing Gracilaria (Magrobacter yixingensis).

4. The method of claim 3, wherein the broth culture medium comprises the following components in the range of S2-S3: 2.8-3.2g/L beef extract, 9.5-10.5g/L peptone, 9.5-10.5g/L sodium chloride and 18-22g/L agar, and sterilizing to obtain broth culture medium with pH of 7.0-8.0.

5. The method according to claim 3, wherein in S4, the selection medium comprises: 0.8-1.2g/L of glucose, 0.15-0.16g/L of ammonium chloride, 0.03-0.04g/L of monopotassium phosphate, 0.046-0.0495g/L of magnesium sulfate, 0.003-0.0035g/L of ferrous sulfate and 30-150g/L of sodium chloride; the solvent is deionized water.

6. The use of the high-salt-resistant COD-reducing strain as claimed in claim 1, wherein the strain is a Magrovirus yixingensis T3 strain, and is used for being inoculated into a biochemical treatment system to treat organic wastewater containing high-concentration sodium chloride.

7. The use of claim 6, wherein the high-concentration sodium chloride wastewater is pharmaceutical wastewater.

8. The application according to claim 6, wherein the method of applying comprises:

step 1: carrying out amplification culture on a strain of Mangrobacter yixingensis T3 to obtain a bacterial solution subjected to amplification culture:

extracting a single colony of Mangrobacter yixingensis T3 in a liquid basal medium, performing shake culture for 20-30h at the temperature of 28-32 ℃ and the rotation speed of 110-;

step 2: inoculating the bacterial liquid into a biochemical treatment system of high-salinity wastewater at an inoculation concentration of 1.8-2.2%.

9. Use according to claim 8, wherein the liquid basal medium comprises: 2.8-3.5g/L beef extract, 8-12g/L peptone and 20-40g/L, pH 7.0.0-8.0 g sodium chloride, and sterilizing;

the whole culture medium contains: 14-16g/L of peptone, 6.5-8.5g/L of yeast powder, 16.5-18.5g/L of disodium hydrogen phosphate dodecahydrate, 6-7.5g/L of potassium dihydrogen phosphate, 3.5-4.5g/L of ammonium sulfate, 0.80-0.92g/L of anhydrous magnesium sulfate, 4-6g/L of glucose, 10-15g/L of glycerol, 20-40g/L of sodium chloride and pH7.0-8.0, and sterilizing to obtain the yeast extract.

10. The use according to claim 6, wherein the COD concentration of the high-concentration sodium chloride wastewater is 10000mg/L or more, and the concentration of sodium chloride is less than or equal to 200 g/L.