Small chain bacillus and its application in degrading polyvinyl alcohol

Abstract

The present application relates to a strain of catellibacterium sp. (Catellibacterium sp.) PVA-1, which is preserved in the China General Microbiological Culture Collection Center (CGMCC) located at No. 1, Yihuangyuan, Beichen West Road, Chaoyang District, Beijing, China, and the preservation number is CGMCC No. 32622. The strain can utilize PVA as the sole carbon source and energy source for growth, and completely mineralize PVA into CO2 and H2O. Under pure culture conditions, the degradation efficiency of PVA in simulated wastewater containing PVA is more than 90% at 30 DEG C and 200 r / min.

Description

TECHNICAL FIELD

[0001] The present application relates to a strain of small chain bacillus, which can efficiently degrade polyvinyl alcohol (PVA) in water bodies, and belongs to the technical field of environmental microorganisms. BACKGROUND

[0002] Polyvinyl alcohol (PVA) is a chemical raw material derived from petroleum cracking products, which has been widely used in many fields such as textiles, paper product manufacturing, food packaging and medical devices due to its excellent water solubility, adhesion, film strength, wear resistance and strong organic solvent resistance. As one of the largest water-soluble polymers, the production and consumption of PVA continue to grow, resulting in a large amount of PVA being discharged into the environment. PVA can quickly form a large amount of foam in water due to its large surface activity, which not only leads to oxygen enrichment in water, but also increases the viscosity of water, seriously inhibiting or even destroying the respiratory activity of aquatic organisms, and thus causing environmental pollution and threatening the ecological balance. Therefore, the degradation and treatment of PVA are crucial for environmental protection.

[0003] However, PVA is difficult to degrade under natural conditions and must be treated by physical and chemical or biological methods. Among them, physical and chemical methods such as ultrafiltration membrane separation, radiation, salting-out flocculation, advanced oxidation and single ozone oxidation, although effective, have the problems of high cost and possible secondary pollution. In contrast, biological degradation of PVA is more economical and efficient.

[0004] Unfortunately, PVA has poor biodegradability and is difficult to be degraded by ordinary microorganisms. However, there are specific functional microorganisms or enzymes that can degrade PVA. Studies have shown that the distribution of these PVA-degrading bacteria in nature is relatively limited, and they are usually found in PVA-contaminated environments such as PVA textile wastewater and papermaking wastewater. Since Nord first discovered that Fusarium can degrade PVA in 1936, researchers have successfully isolated and purified some PVA-degrading bacteria, such as Pseudomonas O-3, Pseudomonas vesicularis PD, Pseudomonas putida, Bacillus magaterium, Acinetobacter sp. and Xanthomonas sp. However, due to low efficiency and other reasons, most of these strains still cannot meet the needs of practical applications. Therefore, screening and isolating efficient PVA-degrading strains has become a core task for developing PVA microbial degradation technology. SUMMARY

[0005] The present application aims at the current situation that the effect of existing polyvinyl alcohol (PVA) degrading strains is not outstanding, and provides a strain of small chain bacillus and its application in degrading polyvinyl alcohol, which can grow by using PVA as the only carbon source and energy source, and then completely mineralize PVA into CO2 and H2O, thereby playing a role in degrading PVA.

[0006] The strain of small chain bacillus PVA-1 is preserved in the China General Microbiological Culture Collection Center, located at No. 1, Beichen West Road, Yard 3, Chinese Academy of Microbiology, Beijing Chaoyang District, and the preservation number is CGMCC No. 32622, and the preservation date is November 14, 2024, and the 16S rDNA sequence thereof is shown as SEQ ID No: 1, and the small chain bacillus in the present application refers to the small chain bacillus PVA-1 strain without special instructions.

[0007] The strain is isolated from activated sludge in a sewage treatment tank, is gram-negative, has no spores, has no capsule, has a cell of 0.6*2.3 microns, and is arranged in pairs and forms a filamentous body, the filamentous body is flat instead of cylindrical, and the terminal cell is not round.

[0008] The beneficial effects of the small chain bacillus provided by the present application are:

[0009] 1) The strain can grow by using PVA as the only carbon source and energy source, and completely mineralize PVA into CO2 and H2O, and under pure culture conditions, the degradation efficiency of PVA in simulated wastewater containing PVA by the strain is more than 90% under the condition of 30 DEG C and 200 r / min.

[0010] 2) The strain has high tolerance to PVA, and can tolerate up to 1000 ppm of PVA, and under pure culture conditions, the degradation rate of 1000 ppm of PVA in inorganic salt medium by the strain is more than 90% in 144 hours;

[0011] 3) The culture method of the strain is simple, the growth speed is fast, the environmental adaptability is strong, the safety is high, the original environment is not destroyed, and there is no secondary pollution.

[0012] The present application also claims to protect a microbial agent containing the above-mentioned small chain bacillus.

[0013] Preferably, the fermentation method of the small chain bacillus comprises the following steps:

[0014] (1) Primary seed culture: under sterile conditions, the small chain bacillus is inoculated into a nutrient medium, and is cultured at 25-35 DEG C and 180-300 r / min for 20-36 hours to obtain a primary seed culture solution;

[0015] (2) Secondary seed culture: under sterile conditions, the primary seed culture solution obtained in step (1) is inoculated into the nutrient medium at a ratio of 1-10 vol%, and cultured at 25-35°C and 180-300 r / min for 20-36 hours to obtain a secondary seed culture solution;

[0016] (3) Fermentation: the fermentation medium is sterilized, and the secondary seed culture solution obtained in step (2) is inoculated into the fermentation medium at a ratio of 1-10 vol%, and fermented at 25-35°C, 180-300 r / min, and an aeration ratio of 1:(1-2), and the pH is adjusted to 6.5-7.5 during the fermentation process. After 20-36 hours, the fermentation is stopped, and a fermentation solution is obtained.

[0017] Further, the nutrient medium has the following composition: 5-15 g / L of tryptone, 3-8 g / L of yeast extract powder, 5-15 g / L of sodium chloride, water as the solvent, and pH = 6.5-8.0.

[0018] Further, the fermentation medium has the following composition: 10-50 g / L of a carbon source, 5-15 g / L of a nitrogen source, 0.1-1.5 g / L of K + , 0.02-0.5 g / L of Mg 2+ , 0.1-0.5 g / L of Ca 2+ , 0.01-0.5 g / L of Mn 2+ , water as the solvent, and pH = 6.5-8.

[0019] Further, the carbon source is selected from one or more of glucose, potassium sodium tartrate, sucrose, starch, succinic acid, or sodium citrate.

[0020] Further, the nitrogen source is selected from one or more of potassium nitrate, diammonium hydrogen phosphate, urea, yeast powder, peptone, or ammonium chloride.

[0021] The ions and salts involved in the medium can all be derived from inorganic compounds. The source of K + is one or more of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, potassium sulfate, potassium chloride, and potassium nitrate. The source of Mg 2+ is one or more of magnesium sulfate and magnesium chloride. The source of Ca 2+ is one or more of calcium chloride and calcium nitrate. The source of Mn 2+ is one or more of manganese sulfate monohydrate, manganese sulfate tetrahydrate, manganese nitrate, and manganese chloride.

[0022] The aeration ratio in the present application refers to the ratio of the volume of air introduced into the fermentation tank per minute to the total volume of the fermentation solution.

[0023] In actual application process, the final small chain bacillus product form can be determined according to actual use and storage needs, when liquid product is needed, the fermentation broth is diluted to the required concentration and directly used, when solid product is needed, the fermentation broth is centrifuged to obtain the bacterial slurry, and then the spray drying or freeze drying process is used to prepare the solid bacterial powder.

[0024] The application also claims to protect the method for purifying the polluted wastewater by using the activated liquid or microbial inoculum of the small chain bacillus, which comprises the step of applying the activated liquid of the small chain bacillus or the microbial inoculum containing the small chain bacillus to the polluted wastewater.

[0025] Further, the polyvinyl alcohol concentration in the polluted wastewater is 1000 mg / L or less, preferably 500 mg / L or less.

[0026] Further, the salinity of the polluted wastewater is 2% or less, preferably 1% or less.

[0027] Further, the inoculation amount of the activated liquid or microbial inoculum of the small chain bacillus is 500 ppm or more, preferably 500-10000 ppm, and most preferably 500-1000 ppm.

[0028] The application also claims to protect the application of the small chain bacillus and the microbial inoculum in the field of polluted wastewater purification.

[0029] Preferably, the small chain bacillus and the microbial inoculum are used for degrading the polyvinyl alcohol in the polluted wastewater.

[0030] Further, the polyvinyl alcohol concentration in the polluted wastewater is 1000 mg / L or less, preferably 500 mg / L or less.

[0031] Further, the salinity of the polluted wastewater is 2% or less, preferably 1% or less. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The colony photo of the small chain bacillus. DETAILED DESCRIPTION

[0033] The principles and characteristics of the application are described below in combination with examples, and the examples are only used to explain the application and not to limit the scope of the application.

[0034] Example 1: Isolation, screening and evaluation of the strain

[0035] 1. Isolation and preliminary screening of the strain

[0036] The activated sludge of a sewage treatment tank of a printing and dyeing factory in Shaanxi was selected for strain enrichment and screening. 5 mL of activated sludge was added to 50 mL of enrichment liquid containing 200 mg / L PVA as the only carbon source, and cultured at 30°C and 200 r / min on a shaking table for 7 days to obtain a round of enrichment liquid. Then 5 mL of the first round of enrichment liquid was transferred to the next round of enrichment liquid containing 500 mg / L PVA as the only carbon source, and cultured for 7 days to obtain a second round of enrichment liquid. The second round of enrichment liquid was gradiently diluted, and the enrichment liquid diluted to 10 -3 、10 -4 、10 -5 concentration was used for strain coating separation. The solid inorganic salt selection medium with PVA as the only carbon source (dipotassium hydrogen phosphate 0.5 g / L, potassium dihydrogen phosphate 0.5 g / L, magnesium sulfate 0.5 g / L, sodium chloride 0.1 g / L, ammonium sulfate 1 g / L, ferrous sulfate heptahydrate 0.01 g / L, manganese sulfate monohydrate 0.01 g / L, agar 20 g / L, PVA 300 mg / L) was used for the plate. After dilution and coating, the plate was inverted and cultured in a 30°C incubator for 48 hours. Then single colonies were picked and purified on nutrient agar plates. The purified single bacteria were transferred to nutrient slant medium and cultured at 30°C for 24 hours, and then transferred to a 4°C refrigerator for standby.

[0037] The screened single bacteria were identified by high-throughput sequencing. After screening out pathogenic bacteria, four strains were finally obtained, which were named PVA-1, PVA-2, PVA-3 and PVA-4.

[0038] 2. Rescreening and evaluation of strains

[0039] Preparation of activation liquid:

[0040] Under sterile conditions, the slant strains of the four strains were inoculated into 250 mL triangular bottles containing 50 mL of LB medium (10 g / L of tryptone, 5 g / L of yeast extract powder, 10 g / L of sodium chloride, solvent being water, and pH = 7.0), and the triangular bottles were cultured in a shaking table at 30°C and 200 r / min for 24 hours to obtain the activation liquid of each strain.

[0041] The evaluation medium (dipotassium hydrogen phosphate 0.5 g / L, potassium dihydrogen phosphate 0.5 g / L, magnesium sulfate 0.5 g / L, sodium chloride 0.1 g / L, ammonium sulfate 1 g / L, ferrous sulfate heptahydrate 0.01 g / L, manganese sulfate monohydrate 0.01 g / L, PVA 400 mg / L) was dispensed into 250 mL triangular bottles, 50 mL of medium per bottle, sterilized at 121°C for 20 minutes, and after the inorganic salts were cooled, sterilized PVA was added to make the concentration of PVA 200 mg / L.

[0042] Evaluation method: 0.1 mL of activated liquid of four strains was added into the evaluation medium respectively, three parallel experiments were set for each group, 0.1 mL of nutrient medium was added into the blank group, the PVA content was detected by centrifugation at regular intervals, the concentration of PVA was determined by I2-KI colorimetric method, and the PVA degradation effect is shown in Table 1.

[0043] Table 1 PVA degradation effect of each strain

[0044]

[0045] As shown in Table 1, strains PVA-1, PVA-2, PVA-3 and PVA-4 all have PVA degradation effect, compared with PVA-2, PVA-3 and PVA-4, strain PVA-1 has more prominent advantages, and can realize PVA degradation rate of more than 90% at 96h, so PVA-1 is selected as the research object.

[0046] 3. Strain identification

[0047] The genomic DNA of strain PVA-1 was extracted, and 16S rDNA was amplified using the genomic DNA as a template. The PCR product was extracted, and DNA sequencing was performed using a sequencer ABI3730-XL. The spliced sequence file was compared with the data in the NCBI 16S database using the NCBI Blast program, the species information with the largest sequence similarity to the tested species was obtained, it was found that it belonged to the Catellibacterium genus and was identified as a small chain bacillus, and was named as small chain bacillus PVA-1.

[0048] Example 2: Strain characteristics exploration

[0049] Preparation of activated liquid: under sterile conditions, the small chain bacillus PVA-1 slope strain was inoculated into a 250mL triangular flask containing 50mL nutrient medium, the triangular flask was placed in a 30℃, 200r / min shaker for 24h, and the activated liquid of the small chain bacillus was obtained for standby.

[0050] 2.1 Temperature tolerance experiment

[0051] The experimental medium was prepared, 10g of tryptone, 5g of yeast extract powder and 10g of sodium chloride were dissolved in 1000mL of distilled water, the pH was adjusted to 6.5-8.0, 50mL of each was divided into 250mL triangular flasks, and sterilized at 121℃ for 20min, and then used.

[0052] Under sterile conditions, inoculate 1 vol% of the activated liquid of small chain bacillus into the experimental medium, and place the reaction system under different temperatures (10°C, 20°C, 30°C, 40°C) at a rotation speed of 200 r / min. Set three parallel groups under each experimental condition, and take samples after 48 h for detection of OD 600 Take the average value to determine the growth condition.

[0053] Table 2 Growth condition of small chain bacillus under different temperatures

[0054] Temperature 24h 48h 72h 10℃ 0.05 0.18 0.20 20℃ 1.2 2.66 2.74 30℃ 1.43 2.97 2.99 40℃ 0.11 0.32 0.44

[0055] As shown in Table 2, the growth condition of small chain bacillus is best at a temperature of 20-30°C, and the growth of the bacterial body is obviously inhibited when the temperature is lower or higher than this temperature. It can also be seen that the optimal growth temperature of the bacteria is 30°C.

[0056] 2.2 Salt tolerance experiment

[0057] Prepare the experimental medium by weighing 10 g of tryptone, 5 g of yeast extract powder and different concentrations of sodium chloride (0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%) in 1000 mL of distilled water, adjust the pH to 6.5-8.0, and divide 50 mL of each into 250 mL triangular bottles, sterilize at 121°C for 20 min, and use as needed.

[0058] Under sterile conditions, inoculate 1 vol% of the activated liquid of small chain bacillus into the experimental medium, and place the reaction system under different temperatures (10°C, 20°C, 30°C, 40°C) at a rotation speed of 200 r / min. Set three parallel groups under each experimental condition, and take samples after 48 h for detection of OD 600 Take the average value to determine the growth condition.

[0059] Table 3 Growth condition of small chain bacillus under different salt concentrations

[0060] Salinity 24h 48h 72h 0.5％ 1.28 2.90 3.24 1.0％ 0.92 2.11 2.51 2％ 0.67 1.54 1.77 3％ 0.32 0.86 1.11 4％ 0.11 0.35 0.75 5％ 0.11 0.21 0.51

[0061] As shown in Table 3, with the increase of salt concentration, the growth of small chain bacillus is inhibited, and the inhibition increases with the increase of salt concentration. When the salt concentration is more than 2.0%, the growth is almost completely inhibited. The salt concentration between 0.5-1.0% is suitable for the growth of small chain bacillus.

[0062] 2.3 pH tolerance experiment

[0063] The experimental medium was configured, and 10 g of tryptone, 5 g of yeast extract powder, and 10 g of sodium chloride were dissolved in 1000 mL of distilled water. The pH was adjusted to 6.5-8.0, 50 mL of each was divided into 250 mL flasks, sterilized at 121°C for 20 min, and then the pH of the medium was adjusted under sterile conditions after cooling. The pH gradient was set to 5.5, 6.5, 7.5, and 8.5.

[0064] Under sterile conditions, 1 vol% of activated small-chain bacillus liquid was inoculated into each experimental medium, and the reaction system was cultured at 30°C and 200 r / min. Three parallel groups were set up under each experimental condition, and samples were taken after 48 h for OD 600 The average value was taken to determine the growth condition.

[0065] Table 4 Growth condition of small-chain bacillus under different pH conditions

[0066]

[0067]

[0068] As shown in Table 4, the pH between 5.5-8.5 has little effect on small-chain bacillus. With the increase of pH, the OD 600 value first increases and then decreases, and the optimum pH is 6.5.

[0069] Example 3: Small-scale experiment of laboratory simulated wastewater medium

[0070] 3.1 PVA tolerance evaluation

[0071] (1) The evaluation medium (dibasic potassium phosphate 0.5 g / L, potassium dihydrogen phosphate 0.5 g / L, magnesium sulfate 0.5 g / L, sodium chloride 0.1 g / L, ammonium sulfate 1 g / L, ferrous sulfate heptahydrate 0.01 g / L, manganese sulfate monohydrate 0.01 g / L) was divided into 250 mL flasks, 50 mL per flask, sterilized at 121°C for 20 min, and then sterilized PVA was added to the medium to make different concentration gradients (200 mg / L, 400 mg / L, 600 mg / L, 1000 mg / L) after cooling.

[0072] (2) Evaluation method: Add small-chain bacillus powder to the evaluation medium, and set the addition amount to 500 mg / L. Three parallel groups were set up for each experiment, and the reaction system was placed at 30°C and 200 r / min. The remaining amount of PVA was detected every day, and the concentration of PVA was determined by I2-KI colorimetric method. The experimental results are shown in Table 5, and the experimental arrangement is as follows:

[0073] Experimental group 1: PVA 200 mg / L;

[0074] Experiment group 2: PVA 400mg / L;

[0075] Experiment group 3: PVA 600mg / L;

[0076] Experiment group 4: PVA 1000mg / L.

[0077] Table 5 Degradation effect of PVA by B. pumilus at different concentrations

[0078]

[0079]

[0080] As shown in Table 5, the tolerance of B. pumilus to PVA can reach 1000mg / L, and it has good degradation effect on PVA within 1000mg / L. It can degrade 200mg / L of PVA to 14mg / L in 96h, with a degradation efficiency of 93%, and can degrade 1000mg / L of PVA to 34mg / L in 144h, with a degradation rate of more than 96%.

[0081] 3.2 Inoculum evaluation

[0082] Different amounts of B. pumilus powder (200mg / L, 500mg / L, 800mg / L) were added to the reaction system, and three parallel samples were set for each addition amount. Then the reaction system was placed at 30℃ and 200r / min, and the residual amount of PVA was detected every day. The concentration of PVA was determined by I2-KI colorimetric method, and the experimental results are shown in Table 6.

[0083] The specific experimental arrangement is as follows:

[0084] Control group: B. pumilus powder 0mg / L;

[0085] Experiment group 1: B. pumilus powder 200mg / L;

[0086] Experiment group 2: B. pumilus powder 500mg / L;

[0087] Experiment group 3: B. pumilus powder 800mg / L.

[0088] Table 6 Degradation effect of PVA by B. pumilus powder at different inoculation amounts

[0089]

[0090] As shown in Table 6, when the concentration of PVA is 500mg / L, the PVA degradation efficiency and degradation rate gradually increase with the increase of the inoculation amount of B. pumilus. Considering the overall economy, the optimal addition amount is set to 500mg / L.

[0091] Example 4: Application experiment in actual wastewater

[0092] 4.1 Experimental supplies

[0093] (1) Experimental water: effluent from the aerobic section of a chemical enterprise in Hunan;

[0094] (2) Experimental bacterial agent: freeze-dried bacterial powder of small chain bacillus;

[0095] 4.2 Evaluation method

[0096] Take 50 mL of experimental water and place it in a 250 mL flask, add small chain bacillus bacterial powder to it, the dosage is set to 500 mg / L, set three parallel groups, and take another group without adding bacterial agent as a blank control. Place the reaction system in a 30°C, 200 r / min environment for evaluation, and detect the remaining amount of PVA every day. The concentration of PVA is determined by the I2-KI colorimetric method.

[0097] 4.3 Experimental results

[0098] Table 7: Degradation effect of small chain bacillus on PVA in actual wastewater

[0099]

[0100] As shown in Table 7, after 144 hours of adding small chain bacillus bacterial powder to the water, the PVA in the water sample decreased to 24 mg / L, and the removal rate of PVA was more than 90%. Compared with the control group, the degradation effect of the experimental group was outstanding.

[0101] Example 5: Fermentation production of small chain bacillus PVA-1

[0102] 1. Fermentation

[0103] 1) First-stage shake flask activation

[0104] In a sterile environment, pick 1 ring of small chain bacillus strain and inoculate into a 250 mL flask containing 100 mL of nutrient medium (yeast extract powder 5 g / L, tryptone 10 g / L, sodium chloride 10 g / L, pH = 7.0, 121°C sterilization for 20 min), and place it in a 30°C, 180 r / min environment for 24 hours to obtain the first-stage activation liquid.

[0105] 2) Preparation of secondary seed liquid

[0106] The first activated liquid was respectively transferred into four 1 L triangular flasks containing 500 mL nutrient medium (yeast extract powder 5 g / L, tryptone 10 g / L, sodium chloride 10 g / L, pH=7.0, sterilized at 121 ℃ for 20 min) in a sterile environment, and cultured at 30 ℃ and 180 r / min for 24 h to obtain the second activated liquid.

[0107] 3) Fermentation culture in 50 L tank

[0108] The fermentation medium was sterilized at 121 ℃ for 20 min, and the final fermentation medium formula was: starch 35 g / L, soybean protein 10 g / L, magnesium sulfate 0.2%, manganese sulfate 0.1%, calcium chloride 0.5%, and dipotassium hydrogen phosphate 0.6%. The second seed culture liquid was inoculated into the fermentation medium at an inoculation amount of 5-10 vol%, and the fermentation tank was filled to 70%. The initial pH was adjusted to 7.0 using sodium hydroxide, and the fermentation culture was carried out at aeration ratio 1:1.25 (m 3 min / m 3 ), 180 rpm, and 30 ℃. During the fermentation process, the pH was controlled to 7 by adding ammonia water. The fermentation period was about 30 h. When the dissolved oxygen began to rise, the fermentation was immediately stopped. At this time, the fermentation was in the late logarithmic phase, the viable cell count of the fermentation broth reached 20 billion CFU / mL, the cell viability was the strongest, the fermentation nutrient residual was the least, and the viable cell count decay was less.

[0109] 2) Post-treatment process of fermentation broth

[0110] To obtain the bacterial powder, the fermentation broth can be treated by the post-treatment process of freeze-drying. After freeze-drying, the viable cell count of the bacterial powder can reach 290 billion CFU / g.

[0111] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A strain of Clostridium paraputrificum (ATCC 21044) characterized by, Catellibacterium sp. The deposit was preserved in China General Microbiological Culture Collection Center, and the preservation number was CGMCC No. 32622. ​ 2. A microbial inoculant, characterized in that, The effective component comprises the small-chain bacillus in claim 1.

3. The fermentation process according to claim 1, characterized in that, The method comprises the following steps: (1) primary seed culture: under sterile conditions, the small-chain bacillus is inoculated into a nutrient medium, and is cultured at 25-35°C and 180-300r / min for 20-36 hours to obtain a primary seed culture solution; (2) secondary seed culture: under sterile conditions, the primary seed culture solution obtained in step (1) is inoculated into a nutrient medium at a proportion of 1-10vol%, and is cultured at 25-35°C and 180-300r / min for 20-36 hours to obtain a secondary seed culture solution; (3) fermentation: the fermentation medium is sterilized, and then the secondary seed culture solution obtained in step (2) is inoculated into the fermentation medium at a proportion of 1-10vol%, and is fermented at 25-35°C, 180-300r / min and a ventilation ratio of 1:(1-2), and the pH is adjusted to 6.5-7.5 during the fermentation process, and the fermentation is stopped after 20-36 hours to obtain a fermentation solution.

4. The fermentation process of claim 3, wherein, The nutrient medium comprises 5-15g / L of tryptone, 3-8g / L of yeast extract powder, 5-15g / L of sodium chloride, and water as a solvent, and the pH is 6.5-8.

0.

5. The fermentation process according to claim 3 or 4, characterized in that, The fermentation medium consists of: carbon source 10-50 g / L, nitrogen source 5-15 g / L, K + 1.0-1.5 g / L, Mg 2+ 0.02-0.5 g / L, Ca 2+ 0.1-0.5 g / L, Mn 2+ 0.01-0.5 g / L, solvent is water, and pH = 6.5-8.

6. The fermentation process of claim 5, wherein, The carbon source is selected from one or more of glucose, potassium sodium tartrate, sucrose, starch, succinic acid or sodium citrate; The nitrogen source is selected from one or more of potassium nitrate, diammonium hydrogen phosphate, urea, yeast powder, peptone or ammonium chloride.

7. A method for purifying polyvinyl alcohol in contaminated waste water, characterized by, The method comprises the step of applying the activated solution of the small-chain bacillus in claim 1 or the microbial agent in claim 2 to the sewage.

8. The method of claim 7, wherein, The concentration of polyvinyl alcohol in the sewage is 1000mg / L or less.

9. The method of claim 8, wherein, The concentration of polyvinyl alcohol in the sewage is 500mg / L or less.

10. The method of claim 7, wherein, The salinity of the sewage is 2% or less.

11. The method of claim 10, wherein, The salinity of the sewage is 1% or less.

Images