A method for improving the ability of sphingosine bacteria to degrade polyvinyl alcohol in printing and dyeing wastewater

Abstract

The present invention discloses a method for improving the ability of sphingosine bacteria to degrade polyvinyl alcohol (PVA) in printing and dyeing wastewater, comprising the following steps: step 1, preparing LB liquid culture medium; step 2, culturing sphingosine bacteria seeds; step 3, culturing sphingosine bacteria to degrade PVA and measuring and analyzing the content of PVA. The present invention improves the ability of sphingosine bacteria to degrade polyvinyl alcohol by adding vegetable oil or waste cooking oil as an inducer and defoaming agent in the process of sphingosine bacteria degrading polyvinyl alcohol in printing and dyeing wastewater.

Description

Technical Field

[0001] The invention belongs to the field of environmental engineering, and in particular relates to a method for improving the ability of sphingosine bacteria to degrade polyvinyl alcohol in printing and dyeing wastewater. Background Art

[0002] Polyvinyl alcohol (PVA) is a highly water-soluble macromolecular polymer, which is widely used in the sizing process in the textile industry to improve fabric performance. Fabrics sized with PVA need to be desized before textile pretreatment, but PVA will be discharged with wastewater after the desizing process. However, PVA has poor biodegradability and high chemical oxygen demand (COD), which makes wastewater biochemical treatment difficult, the residence time is too long, and it is difficult to meet the effluent COD standard, which increases energy consumption and costs.

[0003] It has been found that many bacteria have the ability to degrade PVA, including Sphingobacteria, Pseudomonas, etc., but they all have the disadvantages of weak degradation ability, low efficiency, and long cycle. Therefore, improving the PVA degradation ability of microorganisms can improve the degradation ability of aeration tanks for PVA, save energy and reduce consumption, and reduce effluent COD.

[0004] The expression of PVA-degrading enzymes in the above strains has a certain induction effect. Adding PVA during the culture process can promote the production of microbial PVA-degrading enzymes, but at the same time some PVA cannot be dissolved into flocs. In addition, some short-chain alcohols, such as propylene glycol and butylene glycol, can also increase the expression of PVA-degrading enzymes to a certain extent, but the addition of these fine chemical inducers also creates additional costs. At the same time, these inducers can only increase the activity of intracellular PVA-degrading enzymes. It is not clear whether they can improve the degradation efficiency of PVA by microorganisms in wastewater. Summary of the invention

[0005] Purpose of the invention: In order to solve the above-mentioned problems, the present invention provides a method for adding vegetable oil or waste cooking oil to improve the ability of sphingosine bacteria to degrade polyvinyl alcohol (PVA) in printing and dyeing wastewater. Vegetable oil or waste cooking oil can be used as a microbial defoaming agent and an inducer to enhance the PVA degradation ability during the microbial treatment process.

[0006] Technical solution: A method for improving the ability of sphingosine bacteria to degrade polyvinyl alcohol in printing and dyeing wastewater, characterized in that it comprises the following steps:

[0007] Step 1: Prepare LB liquid culture medium. The specific formula is as follows: peptone 10 g / L, yeast extract 5 g / L, NaCl 10 g / L, 121 o C sterilization for 15 min, and 2% agar was added to the solid medium;

[0008] Step 2: Cultivation of sphingomyelin bacteria seeds. The specific operation is as follows: Inoculate a ring of sphingomyelin bacteria in the LB liquid culture medium prepared in step 1 and place it at 37o C constant temperature shaker, 200 rpm for 48 hours;

[0009] Step 3. Cultivation of sphingobacteria to degrade PVA and determination and analysis of PVA content: The bacterial solution cultured for 48 hours was inoculated with 1% of the PVA-containing wastewater (PVA1799 was added to the printing and dyeing wastewater (taken from the aeration tank of the sewage treatment system of Nantong Qiangsheng Printing and Dyeing Co., Ltd.) to a final concentration of 1g / L), followed by adding vegetable oil or waste cooking oil, taking samples regularly and centrifuging at 10,000 rpm for 1 min, and taking the supernatant to determine the PVA content in the sample.

[0010] In one embodiment of the present invention, in step 2, the vegetable oil or waste cooking oil includes any one or a mixture of more of the following: peanut oil, soybean oil, rapeseed oil or waste cooking oil obtained from daily dining.

[0011] In one embodiment of the present invention, the added amount of the vegetable oil or waste cooking oil is 0.5-2 g / L.

[0012] In one embodiment of the present invention, in step 3, the specific method for determining the PVA content is as follows:

[0013] a. The PVA-containing wastewater sample in the shake flask was centrifuged at 10,000 rpm for 1 min to remove the bacteria, and the supernatant was taken to determine the PVA content;

[0014] b. Add 1 mL of the sample to be tested, 7.5 mL of 25 g / L boric acid and 0.75 mL of I2-KI to a 25 mL colorimetric tube, adjust the volume to 25 mL, and keep it away from light for 10 minutes. Measure the absorbance at 690 nm, calculate the PVA content according to the standard curve, and calculate the PVA degradation rate β (%) according to the following formula:

[0015] β(%)=[(α0-α1)] / α0×100%;

[0016] Among them, α0 represents the PVA content before the reaction, and α1 represents the PVA content after the reaction.

[0017] In one embodiment of the present invention, the I2-KI solution is configured as follows: 10 g / L I2, 80 g / L KI.

[0018] In one embodiment of the present invention, the vegetable oil or waste cooking oil is used as an inducer and defoaming agent, which may promote the entry of PVA into the cell by inducing the expression of PVA enzyme or changing the cell membrane structure of sphingomyelin bacteria, thereby improving the degradation ability of sphingomyelin bacteria to PVA in printing and dyeing wastewater.

[0019] Beneficial effects: The invention improves the ability of sphingosine bacteria to degrade polyvinyl alcohol by adding vegetable oil or waste cooking oil as an inducer and defoamer during the culture process of sphingosine bacteria to degrade PVA. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the relationship between the degraded PVA content and time obtained by adding different types of oil in the present invention. Implementation

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Example

[0022] A method for improving the ability of sphingosine bacteria to degrade polyvinyl alcohol (PVA) in printing and dyeing wastewater, comprising the following steps:

[0023] Step 1: LB liquid medium is prepared as follows: peptone 10 g / L, yeast extract 5 g / L, NaCl 10 g / L, 121 o C for 15 min and add 2% agar to the solid medium.

[0024] Step 2: Cultivation of Sphingosine Bacteria Seeds. The specific operation is as follows: Place a ring of Sphingosine Bacteria in LB liquid culture medium and place at 37 o C incubator at 200 rpm for 48 hours.

[0025] Step 3. Determination and analysis of the PVA degradation ability of sphingobacteria: The bacterial liquid cultured for 48 hours was inoculated with 1% of the PVA-containing wastewater (PVA1799 was added to the printing and dyeing wastewater (taken from the aeration tank of the sewage treatment system of Nantong Qiangsheng Printing and Dyeing Co., Ltd.) to a final concentration of 1g / L), and samples were taken regularly and centrifuged at 10,000 rpm for 1 min. The supernatant was taken to determine the PVA content in the sample.

[0026] Among them, the PVA content determination method is as follows:

[0027] a. The PVA-containing wastewater sample in the shake flask was centrifuged at 10,000 rpm for 1 min to remove the bacteria, and the supernatant was taken to determine the PVA content;

[0028] b. Add 1 mL of the sample to be tested, 7.5 mL of 25 g / L boric acid and 0.75 mL of (10 g / L I2, 80 g / L KI) I2-KI to a 25 mL colorimetric tube, adjust the volume to 25 mL, and let it stand for 10 minutes away from light. Measure the absorbance at 690 nm (the control group is treated the same way), and calculate the PVA content based on the standard curve. The PVA degradation rate β (%) is calculated according to the following formula:

[0029] β(%)=[(α0-α1)] / α0×100%;

[0030] Among them, α0 represents the PVA content before the reaction, and α1 represents the PVA content after the reaction.

[0031] Specific Example 1: Degradation of PVA in printing and dyeing wastewater by sphingobacteria without adding vegetable oil

[0032] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. The culture was carried out in a constant temperature shaker at 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation rate, and samples were taken regularly to determine the PVA content.

[0033] Specific Example 2: Degradation of PVA in printing and dyeing wastewater by sphingobacteria after adding peanut oil

[0034] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. Constant temperature shaker, 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation amount, and 1% peanut oil was added, and samples were taken regularly to determine the PVA content.

[0035] Specific Example 3: Degradation of PVA in printing and dyeing wastewater by sphingobacteria after adding soybean oil

[0036] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. The culture was carried out in a constant temperature shaker at 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation amount, and 1% soybean oil was added. Samples were taken at regular intervals to determine the PVA content.

[0037] Specific Example 4: Degradation of PVA in printing and dyeing wastewater by sphingobacteria after adding rapeseed oil

[0038] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. Constant temperature shaker, 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation amount, and 1% rapeseed oil was added, and samples were taken regularly to determine the PVA content.

[0039] Specific Example 5: Degradation of PVA in printing and dyeing wastewater by sphingobacteria after adding waste oil

[0040] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. The culture was carried out in a constant temperature shaker at 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation amount, and 1% waste oil was added, and samples were taken regularly to determine the PVA content.

[0041] Specific Example 6: Degradation of PVA in printing and dyeing wastewater by sphingobacteria after adding cottonseed oil

[0042] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. The culture was carried out in a constant temperature shaker at 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation amount, and 1% cottonseed oil was added, and samples were taken regularly to determine the PVA content.

[0043] Specific Example 7: Degradation of PVA in printing and dyeing wastewater by sphingobacteria after adding sunflower oil

[0044] From LB solid medium, inoculate a cyclosphingosine seed in LB liquid medium and place at 37 o C. Constant temperature shaker, 200 rpm for 48 hours. Then, the fermentation broth was taken and inoculated into the PVA-containing wastewater at a 1% inoculation amount, and 1% sunflower oil was added, and samples were taken regularly to determine the PVA content.

[0045] from Figure 1 It can be seen that different types of vegetable oils are added in Examples 1-7 as defoaming agents and inducers to enhance the degradation ability of PVA, and the relationship between the degraded PVA content and time can draw the following conclusions: sunflower oil and cottonseed oil are not conducive to the degradation ability of sphingosine bacteria on PVA in printing and dyeing wastewater; peanut oil, soybean oil, rapeseed oil, and gutter oil can all improve the degradation ability of sphingosine bacteria on PVA in printing and dyeing wastewater, among which peanut oil and rapeseed oil have the best effects.

Claims

1. A method for improving the ability of sphingosine bacteria to degrade polyvinyl alcohol (PVA) in printing and dyeing wastewater, characterized in that: The steps include: Step 1: Prepare LB liquid culture medium. The specific formula is as follows: peptone 10 g / L, yeast extract 5 g / L, NaCl 10 g / L, 121 o C sterilization for 15 min, and 2% agar was added to the liquid medium; Step 2: Cultivation of sphingomyelin bacteria seeds. The specific operation is as follows: Inoculate a ring of sphingomyelin bacteria in the LB liquid culture medium prepared in step 1 and place it at 37 o C constant temperature shaker, 200 rpm for 48 hours; Step 3, culturing sphingobacteria to degrade PVA and determining and analyzing the PVA content: the bacterial solution cultured for 48 hours was inoculated with 1% of the PVA-containing wastewater, and the PVA-containing wastewater was obtained by adding PVA1799 to the printing and dyeing wastewater to a final concentration of 1 g / L, and then adding vegetable oil or waste cooking oil, taking samples at regular intervals, centrifuging at 10,000 rpm for 1 min, and taking the supernatant to determine the PVA content; The vegetable oil is one of peanut oil, soybean oil and rapeseed oil; the added amount of the vegetable oil or waste cooking oil is 0.5-2 g / L; The specific determination method of the PVA content is as follows: a. The PVA-containing wastewater sample in the shake flask was centrifuged at 10,000 rpm for 1 min to remove the bacteria, and the supernatant was taken to determine the PVA content; b. Add 1 mL of the sample to be tested, 7.5 mL of 25 g / L boric acid and 0.75 mL of I2-KI solution to a 25 mL colorimetric tube, adjust the volume to 25 mL, and let it stand for 10 minutes away from light. Measure the absorbance at 690 nm, calculate the PVA content according to the standard curve, and calculate the PVA degradation rate β (%) according to the following formula: β（%）=[（α0-α1）] / α0×100%； Among them, α0 represents the PVA content before the reaction, and α1 represents the PVA content after the reaction; The I2-KI solution was prepared as follows: 10 g / L I2, 80 g / L KI; The vegetable oil or waste cooking oil is used as an inducer and defoamer to promote PVA to enter cells by inducing the expression of PVA enzyme or changing the cell membrane structure of sphingosine bacteria, thereby improving the degradation ability of sphingosine bacteria on PVA in printing and dyeing wastewater.

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