Method for embedding and immobilizing sulfur-oxidizing bacteria and application of sulfur-oxidizing bacteria in removal of sulfide in water treatment

Abstract

The invention discloses an embedding immobilization method of sulfur-oxidizing bacteria, which comprises the following steps: performing fermentation culture on the sulfur-oxidizing bacteria to enable the bacteria to be in a logarithmic phase to obtain a sulfur-oxidizing bacteria fermentation liquor, centrifuging the fermentation liquor to obtain mycelia of the sulfur-oxidizing bacteria, emulsifying the mycelia of the sulfur-oxidizing bacteria in a solvent to obtain the sulfur-oxidizing bacteria. The preparation method comprises the following steps: preparing a water-based emulsion, introducing the water-based emulsion into an extruder for extrusion, feeding the extrudate into a spinneret plate to form fibers, and then weaving the fibers into a cloth shape to finish the fiber embedding of bacteria. According to the embedding immobilization method of the sulfur-oxidizing bacteria, cellulose acetate is adopted for embedding the sulfur-oxidizing bacteria, and the method has the advantages that the bacteria are not prone to falling off, and the sulfur oxidation efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to an application of an embedding and immobilizing method of sulfur-oxidizing bacteria in removing sulfide in water treatment. Background Art

[0002] Bacterial immobilization technology is widely used in water treatment units in many industries. The immobilization effect directly affects the number and activity of bacteria. The immobilization methods usually include adsorption, cross-linking and embedding. The embedding materials include sodium alginate, polyvinyl alcohol, carrageenan and gelatin.

[0003] The traditional encapsulation method combines bacteria and encapsulation materials stably to form immobilized microspheres. The above traditional encapsulation method is simple to operate, but has problems such as poor stability and water solubility in application.

[0004] In application number 201410139066.9, a sulfur-oxidizing bacteria sandwich-type multilayer immobilized bioactive filler, preparation and application is proposed. A bioactive filler is granular, composed of an embedding body and a non-woven fabric carrier, and is fixed by secondary cross-linking with boric acid to form a sandwich-type layered filler. This method can effectively solve the problems of poor bacterial adhesion and easy loss, but the preparation method of this active filler is relatively complicated. Summary of the invention

[0005] The object of the present invention is to provide a method for embedding and immobilizing sulfur-oxidizing bacteria to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for embedding and immobilizing sulfur-oxidizing bacteria, comprising the following steps:

[0007] S1: fermenting and culturing the sulfur-oxidizing bacteria to make the bacteria in a logarithmic growth phase to obtain a sulfur-oxidizing bacteria fermentation liquid;

[0008] The configuration of the culture medium used for fermentation culture is as follows:

[0009] 7 g to 9 g of Na2SO3·5H2O, 2.8 g to 3.5 g of KH2PO4, 4 g to 6 g of K2HPO4, 0.5 g to 0.7 g of MgSO4·7H2O, 0.1 g to 0.5 g of KNO3, and 0.1 g to 0.5 g of NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 120° C. to 130° C. for 30 min to 40 min, and cooled after sterilization to obtain the culture medium;

[0010] S2: centrifuging the fermentation broth to obtain mycelium of sulfur-oxidizing bacteria;

[0011] S3: mycelium of sulfur-oxidizing bacteria is emulsified in a solvent to form an aqueous emulsion;

[0012] S4: introducing the aqueous emulsion into an extruder for extrusion;

[0013] S5: The extrudate in step S4 is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

[0014] Preferably, in step S1, the sulfur-oxidizing bacteria include one or a combination of Thiobacillus denitrificans, Thiobacillus thiosulfurans, Thiobacillus ferrooxidans, and Thiobacillus naples.

[0015] Preferably, in any of the above schemes, in step S1, the temperature of the fermentation culture is set to 30-35°C.

[0016] Preferably, in any of the above schemes, in step S2, the centrifugation conditions are 4°C and 5000-10000 rpm.

[0017] Preferably in any of the above schemes, in step S3, the solvent includes cellulose acetate.

[0018] In any of the above schemes, it is preferred that the cellulose acetate includes cellulose diacetate and cellulose triacetate.

[0019] In any of the above schemes, preferably, in step S3, the emulsification time is 6 hours, the temperature is 20-35° C., and during emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to solvent is 1:500-1:1000.

[0020] Preferably, in any of the above schemes, the extruder comprises a single-screw extruder or a twin-screw extruder.

[0021] In any of the above schemes, it is preferred that the conditions of the extruder are set as follows: the extrusion speed of the screw machine is 50-200 rpm, the diameter of the spinneret hole is 0.1 mm-0.3 mm, and the number of holes is 20-50.

[0022] Preferably, in any of the above schemes, in the step of fermenting and culturing the sulfur-oxidizing bacteria, the inoculation amount is 10% to 30%, the pH value is controlled to be 7.0 to 9.0, and the fermentation is carried out for 4 to 7 hours to obtain the sulfur-oxidizing bacteria fermentation liquid.

[0023] Preferably, in any of the above schemes, the fibers are combed and stacked to form a fiber web of a preset thickness, and then the fibers are woven into a cloth-like shape.

[0024] The invention discloses an application of bacterial fiber embedding material prepared by a method for embedding and immobilizing sulfur-oxidizing bacteria in removing sulfide in water treatment.

[0025] The technical effects and advantages of the present invention are as follows: the embedding and immobilization method of sulfur-oxidizing bacteria uses cellulose acetate to embed the sulfur-oxidizing bacteria, which has the advantages that the bacteria are not easy to fall off and the sulfur oxidation efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the process of removing sulfides according to the present invention. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] On the one hand, an embodiment of the present invention provides a method for embedding and immobilizing sulfur-oxidizing bacteria, comprising the following steps:

[0029] S1: Fermenting and culturing the sulfur-oxidizing bacteria to make the bacteria in a logarithmic growth phase to obtain a sulfur-oxidizing bacteria fermentation liquid, wherein the configuration of the culture medium used for the fermentation and culturing is as follows:

[0030] 7 g to 9 g of Na2SO3·5H2O, 2.8 g to 3.5 g of KH2PO4, 4 g to 6 g of K2HPO4, 0.5 g to 0.7 g of MgSO4·7H2O, 0.1 g to 0.5 g of KNO3, and 0.1 g to 0.5 g of NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 120° C. to 130° C. for 30 min to 40 min, and cooled after sterilization to obtain the culture medium;

[0031] S2: centrifuging the fermentation broth to obtain mycelium of sulfur-oxidizing bacteria;

[0032] S3: mycelium of sulfur-oxidizing bacteria is emulsified in a solvent to form an aqueous emulsion;

[0033] S4: introducing the aqueous emulsion into an extruder for extrusion;

[0034] S5: The extrudate in step S4 is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

[0035] Optionally, in step S1, the sulfur-oxidizing bacteria include one or a combination of Thiobacillus denitrificans, Thiobacillus thiosulfurans, Thiobacillus ferrooxidans, and Thiobacillus naples.

[0036] Optionally, in step S1, the temperature of the fermentation culture is set to 30-35°C.

[0037] Optionally, in step S2, the centrifugation conditions are 4°C and 5000-10000 rpm.

[0038] Optionally, in step S3, the solvent includes cellulose acetate.

[0039] Optionally, the cellulose acetate includes cellulose diacetate and cellulose triacetate.

[0040] Optionally, in step S3, the emulsification time is 6 hours, the temperature is 20-35° C., and during emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to solvent is 1:500-1:1000.

[0041] Optionally, the extruder comprises a single-screw extruder or a twin-screw extruder.

[0042] Optionally, the conditions of the extruder are set as follows: the extrusion speed of the screw machine is 50-200 rpm, the diameter of the spinneret hole is 0.1 mm-0.3 mm, and the number of holes is 20-50.

[0043] Optionally, in the step of fermenting and culturing the sulfur-oxidizing bacteria, the inoculation amount is 10% to 30%, the pH value is controlled to be 7.0 to 9.0, and the fermentation is carried out for 4 to 7 hours to obtain the sulfur-oxidizing bacteria fermentation liquid.

[0044] Optionally, the fibers are combed and stacked to form a fiber web of a preset thickness, and then the fibers are woven into a cloth-like shape.

[0045] On the other hand, a method for embedding and immobilizing sulfur-oxidizing bacteria is provided for using a fiber-embedded substance of bacteria for removing sulfide in water treatment.

[0046] Embodiment 1:

[0047] A method for embedding and immobilizing sulfur-oxidizing bacteria comprises the following steps:

[0048] S1: Fermentation culture of denitrifying Thiobacillus, the fermentation culture temperature is set to 30°C, so that the bacteria are in a logarithmic growth phase, and sulfur-oxidizing bacteria fermentation liquid is obtained;

[0049] The configuration of the culture medium used for fermentation culture is as follows:

[0050] 7 g to 9 g of Na2SO3·5H2O, 2.8 g to 3.5 g of KH2PO4, 4 g to 6 g of K2HPO4, 0.5 g to 0.7 g of MgSO4·7H2O, 0.1 g to 0.5 g of KNO3, and 0.1 g to 0.5 g of NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 120° C. to 130° C. for 30 min to 40 min, and cooled after sterilization to obtain the culture medium;

[0051] S2: centrifuging the fermentation broth to obtain mycelium of sulfur-oxidizing bacteria at 4°C and 5000 rpm;

[0052] S3: The mycelium of sulfur-oxidizing bacteria was emulsified in cellulose diacetate to form an aqueous emulsion. The emulsification time was 6 hours and the temperature was 20°C. During the emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to solvent was 1:500.

[0053] S4: The aqueous emulsion is introduced into a single screw extruder for extrusion. The extruder is set to have a screw speed of 50 rpm, a spinneret aperture of 0.1 mm, and 20 holes.

[0054] S5: The extrudate is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

[0055] Embodiment 2:

[0056] A method for embedding and immobilizing sulfur-oxidizing bacteria comprises the following steps:

[0057] S1: fermenting and culturing Thiobacillus thiosulfurans, with the fermentation temperature set at 32°C to keep the bacteria in a logarithmic growth phase, and obtaining a sulfur-oxidizing bacteria fermentation liquid;

[0058] The configuration of the culture medium used for fermentation culture is as follows:

[0059] 7 g of Na2SO3·5H2O, 2.8 g of KH2PO4, 4 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.1 g of KNO3, and 0.1 g of NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 120° C. for 30 min, and cooled after sterilization to obtain the culture medium;

[0060] S2: centrifuging the fermentation broth at 4°C and 8000 rpm;

[0061] S3: The mycelium of sulfur-oxidizing bacteria was emulsified in cellulose triacetate to form an aqueous emulsion. The emulsification time was 6 hours and the temperature was 30°C. During the emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to solvent was 1:800.

[0062] S4: the aqueous emulsion is introduced into a twin-screw extruder for extrusion, and the extruder is set to have a screw extrusion speed of 100 rpm, a spinneret aperture of 0.2 mm, and 30 holes;

[0063] S5: The extrudate is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

[0064] Embodiment 3:

[0065] A method for embedding and immobilizing sulfur-oxidizing bacteria comprises the following steps:

[0066] S1: fermenting and culturing Thiobacillus thiosulfurans, with the fermentation temperature set at 35°C to keep the bacteria in a logarithmic growth phase, and obtaining a sulfur-oxidizing bacteria fermentation liquid;

[0067] The configuration of the culture medium used for fermentation culture is as follows:

[0068] 8 g of Na2SO3·5H2O, 3 g of KH2PO4, 5 g of K2HPO4, 0.6 g of MgSO4·7H2O, 0.3 g of KNO3, and 0.3 g of NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 121° C. for 30 min, and cooled after sterilization to obtain the culture medium;

[0069] S2: centrifuging the fermentation broth at 4°C and 10,000 rpm;

[0070] S3: The mycelium of sulfur-oxidizing bacteria was emulsified in cellulose triacetate to form an aqueous emulsion. The emulsification time was 6 hours and the temperature was 35°C. During the emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to solvent was 1:1000.

[0071] S4: the aqueous emulsion is introduced into a twin-screw extruder for extrusion, and the extruder is set to have a screw speed of 200 rpm, a spinneret aperture of 0.3 mm, and 50 holes during extrusion;

[0072] S5: The extrudate is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

[0073] Embodiment 4:

[0074] A method for embedding and immobilizing sulfur-oxidizing bacteria comprises the following steps:

[0075] S1: fermenting and culturing Thiobacillus thiosulfurans, with the fermentation temperature set at 35°C to keep the bacteria in a logarithmic growth phase, and obtaining a sulfur-oxidizing bacteria fermentation liquid;

[0076] The configuration of the culture medium used for fermentation culture is as follows:

[0077] 9 g Na2SO3·5H2O, 3.5 g KH2PO4, 6 g K2HPO4, 0.7 g MgSO4·7H2O, 0.5 g KNO3, and 0.5 g NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 130° C. for 40 min, and cooled after sterilization to obtain the culture medium;

[0078] S2: centrifuging the fermentation broth at 4°C and 10,000 rpm;

[0079] S3: The mycelium of sulfur-oxidizing bacteria was emulsified in cellulose triacetate to form an aqueous emulsion. The emulsification time was 6 hours and the temperature was 35°C. During the emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to the solvent was 1:900.

[0080] S4: The aqueous emulsion is introduced into a twin-screw extruder for extrusion. The extruder is set to have a screw speed of 150 rpm, a spinneret aperture of 0.25 mm, and 35 holes.

[0081] S5: The extrudate is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

[0082] Comparative Example 1:

[0083] In this comparative example, no immobilization treatment was performed on Thiobacillus denitrificans.

[0084] Comparative Example 2:

[0085] This comparative example adopts the adsorption method to adsorb the denitrifying Thiobacillus on the ceramsite.

[0086] Comparative Example 3:

[0087] In this comparative example, the adsorption method was used to adsorb Thiobacillus denitrificans onto activated carbon.

[0088] Comparative Example 4:

[0089] This comparative example adopts the embedding method for fixation, which is the same as the method in Example 1, except that cellulose diacetate is replaced by gelatin.

[0090] Comparative Example 5:

[0091] This comparative example adopts the embedding method for fixation, which is the same as the method in Example 1, except that the diacetyl cellulose is replaced by polyvinyl alcohol.

[0092] Comparative Example 6:

[0093] This comparative example adopts the embedding method for fixation, which is the same as the method in Example 1, except that cellulose diacetate is replaced by sodium alginate.

[0094] The sodium sulfide prepared in the above Example 1 and Comparative Examples 1-6 were arranged in a bioreactor, the sodium sulfide in the bioreactor influent was controlled at a certain concentration, the aeration volume of the bioreactor was fixed, and the sodium sulfide concentration of the effluent was measured. Figure 1 The results are shown in Table 1 below:

[0095] Table 1

[0096] As can be seen from the above table, the sulfide removal rate of the present invention using cellulose acetate (cellulose diacetate) for embedding is the best, reaching 94.9%. It can be seen that the present invention has the advantages of bacteria not being easy to fall off and high sulfur oxidation efficiency.

[0097]

[0098] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for embedding and immobilizing sulfur-oxidizing bacteria, characterized in that: The following steps are involved: S1: Fermenting and culturing the sulfur-oxidizing bacteria to make the bacteria in a logarithmic growth phase to obtain a sulfur-oxidizing bacteria fermentation liquid, wherein the configuration of the culture medium used for the fermentation and culturing is as follows: 7 g to 9 g of Na2SO3·5H2O, 2.8 g to 3.5 g of KH2PO4, 4 g to 6 g of K2HPO4, 0.5 g to 0.7 g of MgSO4·7H2O, 0.1 g to 0.5 g of KNO3, and 0.1 g to 0.5 g of NH4Cl are dissolved in 1000 ml of deionized water, sterilized at 120° C. to 130° C. for 30 min to 40 min, and cooled after sterilization to obtain the culture medium; S2: centrifuging the fermentation broth to obtain mycelium of sulfur-oxidizing bacteria; S3: mycelium of sulfur-oxidizing bacteria is emulsified in a solvent to form an aqueous emulsion; S4: introducing the aqueous emulsion into an extruder for extrusion; S5: The extrudate in step S4 is fed into a spinneret to form fibers, and then the fibers are woven into a cloth-like shape to complete fiber embedding of bacteria.

2. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: In step S1, the sulfur-oxidizing bacteria include one or a combination of Thiobacillus denitrificans, Thiobacillus thiosulfurans, Thiobacillus ferrooxidans, and Thiobacillus naples.

3. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: In step S1, the temperature of the fermentation culture is set at 30-35°C.

4. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: In step S2, the centrifugation conditions are 4°C and 5000-10000 rpm.

5. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: In step S3, the solvent includes cellulose acetate.

6. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 5, characterized in that: The cellulose acetate includes cellulose diacetate and cellulose triacetate.

7. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: In step S3, the emulsification time is 6 hours, the temperature is 20-35° C., and during emulsification, the ratio of mycelium of sulfur-oxidizing bacteria to solvent is 1:500-1:1000.

8. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: The extruder includes a single-screw extruder or a twin-screw extruder.

9. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: The conditions of the extruder are set as follows: the extrusion speed of the screw machine is 50-200 rpm, the diameter of the spinneret hole is 0.1 mm-0.3 mm, and the number of holes is 20-50.

10. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: In the step of fermenting and culturing the sulfur-oxidizing bacteria, the inoculation amount is 10% to 30%, the pH value is controlled to be 7.0 to 9.0, and the fermentation is carried out for 4 to 7 hours to obtain the sulfur-oxidizing bacteria fermentation liquid.

11. The method for embedding and immobilizing sulfur-oxidizing bacteria according to claim 1, characterized in that: The fibers are combed and stacked to form a fiber web of a preset thickness, and then the fibers are woven into a cloth-like shape.

12. Use of a bacterial fiber embedding material obtained by the embedding and immobilization method of sulfur-oxidizing bacteria according to any one of claims 1 to 11 in removing sulfide in water treatment.

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