Sulfobacillus spp and application thereof in degradation of odor pollutants

Abstract

The invention provides Sulfobacillussp., and the preservation number of the Sulfobacillussp. Is CGMCC (China General Microbiological Culture Collection Center) No.27304. The invention also provides a preparation method of the Sulfobacillussp. The invention also provides an immobilized microbial agent containing the sulfurized bacillus and a preparation method of the microbial agent. The preparation method comprises the following steps: preparing the sulfurized bacillus into a concentrated bacterial suspension; preparing a first mixed solution containing polyvinyl alcohol and sodium alginate, sterilizing the first mixed solution, and adding the sterilized first mixed solution into the concentrated bacterial suspension to prepare a second mixed solution; adding the sterilized bamboo charcoal into the second mixed solution, and uniformly mixing to obtain bamboo charcoal coated with sulfurized bacillus; and adding the bamboo charcoal wrapped with the sulfurized bacillus into a saturated boric acid solution of calcium chloride for crosslinking, and then washing with sterile normal saline. The sulfurized bacillus and the immobilized microbial agent can adapt to an extremely acidic environment with the pH value of 1-2, and efficient degradation of sulfur-containing foul pollutants is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection and treatment, and in particular, relates to a bacillus sulfide and an application thereof in degrading malodorous pollutants. Background Art

[0002] In the field of odor treatment technology, biotrickling filters are widely used due to their low cost, low energy consumption, and convenient operation and management. The principle of biotrickling filters to remove odor pollutants is that the odor pollutants in the odor are captured and utilized by microorganisms attached to the surface of the biotrickling filter packing, part of which is converted into small molecules such as CO2 and H2O, and part of which is converted into energy for the growth and reproduction of the microorganisms themselves, thereby achieving the purpose of removing odor pollutants in the odor.

[0003] The deodorizing microorganisms growing on the inner and outer surfaces of the biotrickling filter tower packing use odorous pollutants as their food source, and obtain the remaining nutrients they need from the circulating fluid. The metabolites of odorous pollutants degraded by the microorganisms are also discharged from the system regularly through the circulating fluid. The circulating fluid is replenished and discharged regularly.

[0004] The main components of sulfur-containing odor pollutants are hydrogen sulfide, methyl mercaptan, methyl sulfide, dimethyl disulfide, carbon disulfide, etc. The efficiency of the biotrickling filter in removing odor pollutants depends on the activity of microorganisms. Overly acidic or overly alkaline environments are not conducive to the growth of microorganisms. The metabolites of sulfur-containing odor pollutants are sulfate ions, which dissolve in the circulating fluid to form a strong acidic environment, which is not conducive to the degradation of odor pollutants by degradation microorganisms. In order to solve the problem of strong acidic metabolites inhibiting the activity of microorganisms, the current commonly used measure is to regularly replace the circulating fluid, that is, to regularly discharge the strongly acidic circulating fluid and regularly replenish fresh circulating fluid. This measure can effectively solve the problem of acidic metabolites inhibiting the activity of microorganisms, but the disadvantage is that the drainage frequency is high and the water consumption and energy consumption are high. For some system water with low automation and manual drainage, the high frequency of manual drainage will lead to high operating costs.

[0005] Therefore, providing a degradation microorganism that can resist strong acidic environment and effectively remove sulfur-containing odor pollutants is a technical problem that urgently needs to be solved. Summary of the invention

[0006] The purpose of the present invention is to provide a Bacillus sulfide that can resist a strong acidic environment and effectively remove sulfur-containing malodorous pollutants, and its application in degrading malodorous pollutants in view of the deficiencies of the prior art.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] In one aspect, the present invention provides a Sulfobacillus sp., whose deposit number is CGMCC No.27304.

[0009] In another aspect, the present invention provides an immobilized microbial agent comprising the Bacillus sulfide of the present invention.

[0010] In another aspect, the present invention provides a method for preparing an immobilized microbial agent, comprising the following steps:

[0011] (1) preparing the Bacillus sulfide of the present invention into a concentrated bacterial suspension;

[0012] (2) preparing a first mixed solution comprising polyvinyl alcohol and sodium alginate, wherein the first mixed solution is sterilized and then added to the concentrated bacterial suspension to prepare a second mixed solution;

[0013] (3) adding the sterilized bamboo charcoal into the second mixed solution and mixing evenly to obtain bamboo charcoal encapsulating Bacillus sulfide;

[0014] (4) adding the bamboo charcoal encapsulating the Bacillus sulfide into a saturated boric acid solution of calcium chloride for cross-linking, and then washing with sterile saline to obtain the immobilized microbial agent.

[0015] According to some embodiments of the present invention, in step (1), the OD of the concentrated bacterial suspension is 600 The value is 2.0~2.5.

[0016] Optionally, the concentrated bacterial suspension can be prepared by a method comprising the following steps:

[0017] The sulfhydryl bacillus of the present invention is made into OD 600 The value is 0.8 for the culture solution;

[0018] Centrifuging the culture solution, removing the supernatant, washing the solid obtained by centrifugation, and then collecting the bacterial cells;

[0019] The cells were washed with PBS buffer and then diluted with saline to an OD of 600 The value is 2.0-2.5, thereby obtaining the concentrated bacterial suspension.

[0020] According to some embodiments of the present invention, in step (2), the first mixed solution comprises 1 wt% to 3 wt% polyvinyl alcohol and 1 wt% to 3 wt% sodium alginate;

[0021] Preferably, the first mixed solution comprises 3wt% polyvinyl alcohol and 1wt% sodium alginate, or the first mixed solution comprises 2wt% polyvinyl alcohol and 1wt% sodium alginate, or the first mixed solution comprises 1wt% polyvinyl alcohol and 1wt% sodium alginate, or the first mixed solution comprises 1wt% polyvinyl alcohol and 2wt% sodium alginate, or the first mixed solution comprises 1wt% polyvinyl alcohol and 3wt% sodium alginate;

[0022] More preferably, the first mixed solution comprises 2 wt % polyvinyl alcohol and 1 wt % sodium alginate.

[0023] According to some embodiments of the present invention, in step (2), the volume ratio of the first mixed solution to the concentrated bacterial suspension is 100:(10-50).

[0024] According to some embodiments of the present invention, in step (3), the bamboo charcoal is added to the second mixed solution at a concentration of 30 g / L to 60 g / L.

[0025] According to some embodiments of the present invention, in step (3), the particle size of the bamboo charcoal is 5 to 10 mm, and the specific surface area is not less than 280 m 2 / g, the apparent density is not less than 0.32g / mL, the strength is not less than 99%, and the micropore ratio is not less than 85%. Among them, the micropore ratio refers to the pores with a pore diameter less than 2nm.

[0026] According to some embodiments of the present invention, in step (4), the bamboo charcoal wrapped with Bacillus sulfide is added to a saturated boric acid solution of 1wt% to 5wt% calcium chloride at 3 to 10°C for cross-linking; wherein the amount of the saturated boric acid solution of calcium chloride is 0.4 to 4L / g, that is, the lower limit of the amount of the saturated boric acid solution cross-linked per gram of bamboo charcoal particles wrapped with Bacillus sulfide is 0.4L, and the upper limit is 4L.

[0027] Preferably, the cross-linking time is 6 hours to 48 hours, more preferably 24 hours.

[0028] In another aspect, the present invention provides use of the Bacillus sulfide of the present invention or the immobilized microbial agent of the present invention in degrading odor pollutants.

[0029] In another aspect, the present invention provides a biotrickling filter, wherein the filler of the biotrickling filter comprises the Bacillus sulfidus of the present invention or the immobilized microbial agent of the present invention;

[0030] Preferably, the filler of the biological trickling filter contains 30% to 60% of the immobilized microbial agent based on the total volume of the filler. The immobilized microbial agent is filled as filler in the middle of the filter bed of the biological trickling filter, and the upper and lower edges of the filled immobilized microbial agent filler are at least 20 cm away from the top and bottom of the filter bed.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The Bacillus sulfide and the immobilized microbial agent provided by the present invention can efficiently degrade sulfur, thereby achieving efficient degradation of odor pollutants. The inventors have proved through experiments that when the Bacillus sulfide of the present invention is added to a degradation medium containing sulfur and subjected to oscillation treatment, a removal rate of more than 99% can be achieved for sulfur with an initial concentration of 5 g / L.

[0033] (2) The immobilized microbial agent provided by the present invention uses bamboo charcoal with a large specific surface area and high mechanical strength as an attachment carrier. By utilizing the adsorption properties of bamboo charcoal, Bacillus sulfidus, which can efficiently degrade sulfur, can be fixed on the bamboo charcoal filler, thereby improving the removal rate of odor pollutants and effectively preventing the loss of the agent.

[0034] (3) The immobilized microbial agent provided by the present invention can be used for the treatment of sulfur-containing odor pollutants, thereby improving the removal efficiency of sulfur-containing odor pollutants. In addition, the agent adopts a biocompatible inorganic carrier, has no secondary pollution, and has huge environmental benefits.

[0035] (4) The Bacillus sulfide or immobilized microbial agent provided by the present invention can be applied to the treatment of sulfur-containing malodorous pollutants. By inoculating it into the filler of the biological deodorization tower, the Bacillus sulfide can be rapidly enriched in the tower body, and can adapt to the spraying environment with a pH value as low as 1, thereby reducing the frequency of water changes in the biological deodorization tower, saving water costs, and solving the problem of high operating costs caused by the high frequency of artificial drainage, thereby having huge economic benefits.

[0036] Collection Information

[0037] Sulfobacillus sp., named Desulp-III, deposit number: CGMCC No.27304, deposit date: May 9, 2023, deposit unit: General Microbiology Center of China Culture Collection Administration (CGMCC), address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a curve showing the change in sulfur concentration during sulfur degradation by the strain Desulp-III in Example 1 of the present invention.

[0039] Figure 2 This is a curve showing the change in sulfate ion concentration during the degradation of elemental sulfur by the strain Desulp-III in Example 1 of the present invention.

[0040] Figure 3 This is the growth curve of strain Desulp-III in Example 1 of the present invention.

[0041] Figure 4 3 is the degradation curve of elemental sulfur by the immobilized microbial agent with different carrier ratios in Example 3 of the present invention, wherein the carrier ratio in the figure refers to the weight ratio of polyvinyl alcohol to sodium alginate.

[0042] Figure 5 This is the degradation curve of elemental sulfur by the immobilized microbial agent with different cross-linking times in Example 4 of the present invention.

[0043] Figure 6 This is the effect curve of different pH values ​​on the degradation of elemental sulfur by the immobilized microbial agent in Example 5 of the present invention.

[0044] Figure 7 This is the degradation curve of elemental sulfur by the immobilized microbial agent, free microbial agent and immobilized carrier in Example 6 of the present invention.

[0045] Figure 8 This is the degradation curve of hydrogen sulfide by the biological deodorization tower inoculated with the immobilized microbial agent in Example 7 of the present invention.

[0046] Fig. 9 This is a curve showing the change of pH value of the circulating liquid of the biological deodorization tower with the operating time in Example 7 of the present invention. DETAILED DESCRIPTION

[0047] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods without specific conditions in the following examples are based on conventional methods and conditions.

[0048] First, the culture medium, detection method, etc. used in the following examples are described as follows:

[0049] The formula of the improved 9K liquid medium is: ammonium sulfate 3g / L, potassium hydrogen phosphate 0.5g / L, magnesium sulfate heptahydrate 0.5g / L, potassium chloride 0.1g / L, calcium chloride 6.8mg / L, potassium nitrate 6.2mg / L, elemental sulfur 5g / L, yeast extract 0.3g / L, pH 2-2.5. The improved 9K solid medium is based on the improved 9K liquid medium and adds 15g / L agar.

[0050] PBS buffer (pH 7.2-7.4) formula: sodium chloride 8 g / L, potassium chloride 0.2 g / L, disodium hydrogen phosphate 1.44 g / L, potassium dihydrogen phosphate 0.24 g / L.

[0051] OD 600 It refers to the absorbance value of bacterial suspension at a wavelength of 600nm, which is used to indicate the concentration of bacterial suspension.

[0052] Method for determining sulfur element concentration: methylene blue spectrophotometry. The principle is that sulfur ions react with p-aminodimethylaniline in an acidic solution containing ferric ions to generate methylene blue dye. The absorbance is measured at a wavelength of 665nm, and its blue color is proportional to the sulfur ion content in the water sample.

[0053] Method for determining sulfate ion concentration: turbidimetric method. The principle is that sulfate in water reacts with barium ions in an acidic medium to form suspended barium sulfate crystals, making the solution turbid. The absorbance is measured at a wavelength of 410nm, and the degree of turbidity is proportional to the sulfate ion concentration.

[0054] Example 1: Isolation, screening and identification of Bacillus sulfide Desulp-III

[0055] The Bacillus sulfide Desulp-III of the present invention is separated, screened and identified from the filler of a biotrickling filter that has long-term stable operation and excellent deodorization effect. The specific process is as follows:

[0056] (1) Preparation of initial bacterial suspension sample

[0057] 1g of carbon filler was taken from the bottom of the bed of a biotrickling filter in good operating condition, soaked in sterile saline, and then placed in an ultrasonic cleaner for ultrasonic vibration for 10 minutes. After filtering to remove large pieces of carbon filler, a suspension rich in deodorizing bacteria was obtained.

[0058] (2) Enrichment of bacterial strains

[0059] Take 2 ml of the supernatant of the suspension in step (1) and inoculate it into 150 ml of modified 9K liquid culture medium for 3-5 days at 30°C and 150 r / min. After 3-5 days, take 5 ml of the liquid culture medium and transfer it into fresh modified 9K medium and culture it for 3-5 days under the same culture conditions. After 14 transfers, the enriched bacterial liquid is obtained.

[0060] (3) Initial screening of bacterial strains

[0061] Take 0.1 mL of the enriched bacterial solution obtained in step (2) and inoculate it on a modified 9K solid culture medium plate, spread it evenly with a triangular spreading rod, and culture it in a constant temperature incubator at 30°C for 2 days, pick out the colonies with differences from the plate and draw lines. After drawing lines twice, four pure colonies were obtained and numbered Desulp-I, Desulp-II, Desulp-III, and Desulp-IV.

[0062] (4) Rescreening of bacterial strains

[0063] The pure colonies in step (3) were picked and inoculated into the modified 9K liquid medium. After culturing for 48 hours, the cells were centrifuged and washed twice with 0.9% saline. Then, the cells were adjusted to OD 600 The value of the bacterial suspension was 0.8. 5 mL of the bacterial suspension was transferred to a modified 9K liquid medium containing 5 g / L sulfur. Another 5 mL of sterilized saline was transferred to a modified 9K liquid medium containing 5 g / L sulfur as a blank group. The mixture was placed in an incubator at 30°C and 150 r / min for 10 days. The sulfur concentration and sulfate ion concentration were measured on the 5th and 10th days. The results are shown in Table 1 below.

[0064] Table 1

[0065]

[0066] The results showed that the four bacteria all had a certain degradation effect on elemental sulfur. The removal rates of elemental sulfur on the 10th day were 57%, 72%, 81% and 26% respectively. Among them, Desulp-III had the best degradation effect on elemental sulfur, and the concentration of sulfate ions produced by metabolism on the 10th day was also the highest.

[0067] Next, a pure colony numbered Desulp-III was selected and inoculated into a modified 9K liquid medium. After culturing for 48 hours, the culture was centrifuged, the cells were washed twice with 0.9% saline, and then the cells were adjusted to OD 600 5 mL of bacterial suspension was transferred to a modified 9K liquid medium containing 5 g / L sulfur. Another 5 mL of sterilized saline was transferred to a modified 9K liquid medium containing 5 g / L sulfur as a blank group. The mixture was placed in an incubator at 30°C and 150 r / min for 10 days. The sulfur concentration and sulfate ion concentration were measured every day. Figure 1 This is the curve of the change of sulfur concentration during the degradation of sulfur by strain Desulp-III. Figure 2 This is the curve of the change of sulfate ion concentration during the degradation of sulfur by strain Desulp-III. Figure 1It can be seen that on the 10th day, the removal efficiency of the strain Desulp-III for elemental sulfur with an initial concentration of 5 g / L was 80%.

[0068] (5) Identification of bacterial species

[0069] (5.1) Laboratory Identification:

[0070] The slides were prepared by Gram staining, and the strain Desulp-III obtained by the rescreening in step (4) was observed under an electron microscope to be stained purple, so the strain Desulp-III was identified as a Gram-positive bacterium.

[0071] According to the Manual of Identification of Common Bacteria (2001, ISBN 7-03-008460-8), the strain Desulp-III meets the characteristics of the genus Sulfobacillus. The strain is resistant to high temperatures and strong acids; it is an aerobic rod-shaped bacterium, strictly aerobic, and facultative chemoautotrophic bacterium; it can grow autotrophically with ferrous iron, elemental sulfur, and sulfide as raw materials. In the process of sulfur oxidation, hydrogen sulfide, elemental sulfur, and sulfite are gradually oxidized and degraded.

[0072] (5.2) Outsourcing appraisal:

[0073] Shanghai Maipu Biotechnology Co., Ltd. was commissioned to identify the strain Desulp-III obtained by the rescreening in step (4), and it was finally identified as Sulfobacillus sp.

[0074] (6) Optimal process parameters for fermentation tank culture

[0075] The optimal growth environment of strain Desulp-III was studied by controlling the variable method, and finally the optimal process parameters for fermentation culture of strain Desulp-III were determined to be stirring speed 190r / min, pH value 2.0, temperature 50℃, and optimal culture time 4 days.

[0076] The growth curve of strain Desulp-III was studied by the following steps:

[0077] (6.1) Determine the OD600 value of strain Desulp-III at different times in modified 9K liquid medium;

[0078] (6.2) Use physiological saline to treat the OD measured in step (6.1) 600 The concentration gradient of different bacterial suspensions was 10 -1The bacterial suspension was diluted and the appropriate dilution multiple was selected. 0.1 mL was inoculated on the solid culture medium plate and evenly spread with a triangular spreading rod. After culturing in a constant temperature incubator (temperature 50°C) for 2 days, the plate that can be isolated with a single colony was selected for counting. The number of bacteria contained in the original bacterial suspension was calculated according to the dilution multiple, in units of cfu / mL. 600 When the value is 0.8, the corresponding strain Desulp-III is 2.4×10 8 cfu / mL.

[0079] The growth curve of strain Desulp-III is as follows Figure 3 shown.

[0080] Example 2: Preparation of immobilized microbial agent

[0081] (1) Prepare the isolated Sulfobacillus sp. strain Desulp-III into OD 600 The culture medium was centrifuged at 10000r / min for 10min, the supernatant was removed, the bacteria were resuspended and washed with PBS buffer, the washing was repeated 3 times, the bacteria were collected, and then diluted with physiological saline to OD 600 is about 2, and OD is obtained 600 It is a bacterial suspension of about 2.

[0082] (2) A first mixed solution containing 2 wt % polyvinyl alcohol and 1 wt % sodium alginate was prepared, and the first mixed solution was sterilized in a high pressure steam sterilizer. The sterilization conditions of the high pressure steam sterilizer were: a pressure of 0.1 MPa, i.e., 103.4 kPa (1.05 kg / cm 2 ) steam pressure; when the temperature reaches 121°C, maintain it for 30 minutes. The sterilized first mixed solution is cooled to room temperature and then added to the bacterial suspension of step (1) to form a second mixed solution, wherein the ratio (volume ratio) of the first mixed solution to the bacterial suspension is 100:20.

[0083] (3) Sterilize bamboo charcoal particles with a particle size of 5 to 10 mm in a high pressure steam sterilizer. The specific surface area of ​​the bamboo charcoal particles is not less than 280 m 2 / g, apparent density not less than 0.32g / mL, strength not less than 99%, micropore ratio not less than 85%. The sterilization conditions of high pressure steam sterilizer are: 0.1MPa pressure, i.e. 103.4kPa (1.05kg / cm 2 ) steam pressure; when the temperature reaches 121°C, maintain it for 30 minutes. The sterilized bamboo charcoal particles are cooled to room temperature, and then added to the second mixed solution at a concentration of 50g / L and mixed thoroughly to allow the bamboo charcoal particles to encapsulate the Bacillus sulfidus Desulp-III.

[0084] (4) At 4°C, the bamboo charcoal particles encapsulating the Bacillus sulfide Desulp-III obtained in step (3) were slowly placed one by one into a saturated boric acid solution containing 2wt% CaCl2, with the amount of saturated boric acid solution being 0.4L / g. After cross-linking for 24 hours, the bamboo charcoal particles were taken out and washed three times with sterile saline to obtain an immobilized microbial agent.

[0085] Example 3: Effect of carrier ratio on sulfur degradation by immobilized microbial agents

[0086] The following five groups of mixed solutions containing polyvinyl alcohol and sodium alginate (i.e., five carrier ratios) were prepared respectively:

[0087] Group 1: containing 3wt% polyvinyl alcohol and 1wt% sodium alginate, that is, the weight ratio of polyvinyl alcohol to sodium alginate is 3:1;

[0088] Group 2: containing 2wt% polyvinyl alcohol and 1wt% sodium alginate, i.e., the weight ratio of polyvinyl alcohol to sodium alginate is 2:1;

[0089] Group 3: containing 1wt% polyvinyl alcohol and 1wt% sodium alginate, that is, the weight ratio of polyvinyl alcohol to sodium alginate is 1:1;

[0090] Group 4: containing 1wt% polyvinyl alcohol and 2wt% sodium alginate, that is, the weight ratio of polyvinyl alcohol to sodium alginate is 1:2;

[0091] Group 5: contains 1wt% polyvinyl alcohol and 3wt% sodium alginate, that is, the weight ratio of polyvinyl alcohol to sodium alginate is 1:3.

[0092] The method of Reference Example 2 was used to prepare immobilized microbial agents with five different carrier ratios (ie, the weight ratio of polyvinyl alcohol to sodium alginate).

[0093] The ability of these five immobilized microbial agents to degrade sulfur was tested. The specific method was as follows: 4 g of each of the five immobilized microbial agents was weighed and added to 150 ml of modified 9K liquid culture medium. The culture was placed in an incubator at 30°C and 150 r / min for 10 days. The sulfur concentration was measured every day during the culture period. The results were as follows: Figure 4 shown.

[0094] from Figure 4 It can be seen that the immobilized microbial agents prepared using the above five mixed solutions containing polyvinyl alcohol and sodium alginate can effectively remove sulfur. In particular, when the mixed solution contains 2wt% polyvinyl alcohol and 1wt% sodium alginate, the obtained immobilized microbial agent can achieve a sulfur removal efficiency of more than 99% on the 8th day, and the degradation rate is better than that of the immobilized microbial agents prepared by other mixed carriers. The inventors analyzed the reasons as follows:

[0095] Compared with synthetic polymer polyvinyl alcohol, bamboo charcoal and sodium alginate from nature have better biocompatibility; at the same time, compared with sodium alginate, hard bamboo charcoal and synthetic polymer polyvinyl alcohol have higher mechanical strength and wider adjustable range of mechanical properties. Mixing the three carriers in a certain proportion can effectively make up for the shortcomings of the two carrier materials, so that the immobilized microbial agent has a reasonable pore structure, which is conducive to the growth and reproduction of microorganisms and the transmission of nutrients and metabolites. At the same time, it has the advantages of high mechanical strength, and the effective agent is not easy to dissolve, which improves the chemical stability of the immobilized microbial agent. All of these are conducive to the degradation and removal of elemental sulfur.

[0096] Example 4: Effect of different cross-linking times on the degradation of sulfur by immobilized microbial agents

[0097] The method in Example 2 was adopted, but the cross-linking time was set to 6 hours, 12 hours, 24 hours and 48 hours, respectively, to prepare immobilized microbial agents with 4 different cross-linking times.

[0098] The ability of these four immobilized microbial agents to degrade sulfur was tested. The specific method was as follows: 4 g of each of the four immobilized microbial agents were weighed, added to 150 ml of modified 9K liquid culture medium, and cultured in an incubator at 30°C and 150 r / min for 10 days. The sulfur concentration was measured every day during the culture period. The results were as follows: Figure 5 shown.

[0099] from Figure 5 It can be seen that within a certain range, with the increase of cross-linking time, the removal rate of elemental sulfur by immobilized microbial agents gradually increases. This is because the cross-linking time is too short to support the cross-linking calcification of polyvinyl alcohol and sodium alginate on the surface of bamboo charcoal to form a certain mechanical strength. During the degradation process, the effective agent is easily dissolved, which is not conducive to the growth and reproduction of the agent. When the cross-linking time is 24h, 99% of elemental sulfur can be removed on the 8th day, which is the optimal cross-linking time. As the cross-linking time exceeds 24h and continues to increase, the removal rate decreases. This is because after the surface calcification of the immobilized microbial agent forms a certain strength, if the cross-linking time is longer and the cross-linking density is higher, although the mechanical strength will also be enhanced, the transmission of nutrients and metabolites will be subject to greater resistance, which is not conducive to the growth and metabolism of microorganisms, thereby reducing the degradation rate of elemental sulfur.

[0100] In general, when the cross-linking time is within the range of 6 to 48 hours, the prepared immobilized microbial agents can effectively remove elemental sulfur, and the optimal cross-linking time is 24 hours.

[0101] Example 5: Effect of pH on the degradation of elemental sulfur by immobilized microbial agents

[0102] Improved 9K liquid culture medium was prepared and divided into 5 portions, and the pH values ​​thereof were adjusted to 1, 2, 4, 7, and 9 respectively with dilute sulfuric acid and sodium hydroxide. High pressure steam sterilization was performed using the sterilization method in Example 2, and then cooled to room temperature.

[0103] Weigh 4 g of the immobilized microbial agent prepared in Example 2, add them to 150 ml of modified 9K liquid culture medium at pH 1, pH 2, pH 4, pH 7, and pH 9, respectively, place them in an incubator at 30°C and 150 r / min for 10 days, and measure the sulfur concentration every day. The results are as follows: Figure 6 shown.

[0104] from Figure 6 It can be seen that the immobilized microbial agent of the present invention can effectively degrade sulfur in the range of pH 1 to 7. In particular, the optimal pH value of the immobilized microbial agent of the present invention is 2, and a removal rate of more than 99% of sulfur can be achieved on the 8th day of culture. This result is consistent with the description on page 63 of the "Common Bacteria System Identification Manual" that "Sulfobacillus (Sulfobacillus Golovachova & Karavaiko, 1991) has an optimal pH of 1.9 to 2.4". In addition, the immobilized microbial agent of the present invention still maintains a high removal rate for sulfur in an environment with a pH value of 1, and a removal rate of more than 99% of sulfur is achieved on the 9th day of culture, indicating that the immobilized microbial agent can adapt to an extremely acidic environment of pH 1 to 2.

[0105] Example 6: Degradation of elemental sulfur by immobilized microbial agents, free microbial agents, and immobilized carriers

[0106] The OD of strain Desulp-III was prepared according to the method of step (4) in Example 1. 600 It is a bacterial suspension of 0.8, that is, free bacterial agent.

[0107] The preparation method of the immobilized carrier is similar to that of Example 2, except that step (1) of Example 2 is omitted and an equal volume of sterilized saline is used instead of OD 600 It is a bacterial suspension of about 2. The specific method is as follows:

[0108] (1') A first mixed solution containing 2 wt% polyvinyl alcohol and 1 wt% sodium alginate is prepared, and the first mixed solution is sterilized in a high pressure steam sterilizer. The sterilization conditions of the high pressure steam sterilizer are: a pressure of 0.1 MPa, i.e., 103.4 kPa (1.05 kg / cm 2 ) steam pressure; when the temperature reaches 121°C, maintain it for 30 minutes. The sterilized first mixed solution is cooled to room temperature and then added to the sterilized saline to form a third mixed solution, wherein the ratio of the first mixed solution to the saline is 100:20.

[0109] (2') Sterilize bamboo charcoal particles with a particle size of 5 to 10 mm in a high pressure steam sterilizer. The specific surface area of ​​the bamboo charcoal particles is not less than 280 m 2 / g, apparent density not less than 0.32g / mL, strength not less than 99%, micropore ratio not less than 85%. The sterilization conditions of high pressure steam sterilizer are: 0.1MPa pressure, i.e. 103.4kPa (1.05kg / cm 2 ) steam pressure; when the temperature reaches 121°C, maintain it for 30 minutes. The sterilized bamboo charcoal particles are cooled to room temperature, and then added to the third mixed solution at a concentration of 50g / L and mixed thoroughly.

[0110] (3') At 4°C, the bamboo charcoal particles obtained in step (2') are slowly placed into a saturated boric acid solution containing 2 wt% CaCl2, with the amount of the saturated boric acid solution being 0.4 L / g. After cross-linking for 24 hours, the bamboo charcoal particles are taken out and washed three times with sterile saline to obtain a sterile agent immobilization carrier.

[0111] 4 g of the above-mentioned free bacterial agent and immobilized carrier and the immobilized microbial agent prepared in Example 2 were weighed and added to 150 ml of improved 9K liquid culture medium, respectively, and placed in an incubator at 30°C and 150 r / min for 10 days. During this period, the sulfur concentration was measured every day. The results are as follows: Figure 7 shown.

[0112] from Figure 7 It can be seen that compared with the blank group (immobilized carrier) and the control group (free agent), the immobilized microbial agent of the present invention can achieve more than 99% degradation of sulfur within 8 days, and the effect is better than that of the free agent and the immobilized carrier group. This is because the immobilized microbial agent makes full use of the adsorption characteristics of bamboo charcoal and can adsorb sulfur on the surface of bamboo charcoal; on the other hand, due to the excellent adsorption performance of bamboo charcoal, polyvinyl alcohol and sodium alginate can be adsorbed on the surface of bamboo charcoal, forming a high degree of cross-linking between each other, and on the premise of forming sufficient mechanical strength, Bacillus sulfide can also be embedded and fixed inside the carrier, thereby reducing the loss of effective agents; furthermore, the scientific ratio of the three carriers of polyvinyl alcohol, sodium alginate and bamboo charcoal makes the immobilized microbial agent have a reasonable pore structure, which is conducive to the growth and reproduction of microorganisms and the transmission of nutrients and metabolites.

[0113] Example 7: Practical application of immobilized microbial agents in biotrickling filters

[0114] Application method: The immobilized microbial agent prepared in Example 2 is used as a filler in the biological trickling filter and filled in the middle of the filter bed. The filling amount is 40% of the total volume of the filler. When the filler filter adopts the lower air intake and upper air outlet, the lower edge of the filled immobilized microbial agent filler is 0.3m away from the bottom of the filter bed, and the upper edge is 0.5m away from the top of the filter bed.

[0115] The immobilized bacterial agent obtained by the above method was applied to the biological trickling filter deodorization tower of a sewage pumping station in East China, and the inlet and outlet hydrogen sulfide concentrations were tested every day. Figure 8 As shown in the figure, when the inlet hydrogen sulfide concentration is 20-80ppm, the trickling filter inoculated with the immobilized bacterial agent can complete the acclimation of the biological deodorization tower on the 8th day. From the 8th day onwards, the removal rate of the inlet hydrogen sulfide can reach more than 99%. At the same time, the pH of the circulating liquid during the commissioning period was measured, and the results are as follows Fig. 9 As shown, the pH value of the circulating liquid of the biotrickling filter tower after debugging and stabilization is stable between 1 and 3.

Claims

1. A Sulfobacillus sp., characterized in that: Its deposit number is CGMCC No.27304.

2. An immobilized microbial agent, characterized in that: It comprises the Bacillus sulfide according to claim 1.

3. A method for preparing an immobilized microbial agent, characterized in that: It includes the following steps: (1) preparing the Bacillus sulfide described in claim 1 into a concentrated bacterial suspension; (2) preparing a first mixed solution comprising polyvinyl alcohol and sodium alginate, wherein the first mixed solution is sterilized and then added to the concentrated bacterial suspension to prepare a second mixed solution; (3) adding the sterilized bamboo charcoal into the second mixed solution and mixing evenly to obtain bamboo charcoal encapsulating Bacillus sulfide; (4) adding the bamboo charcoal encapsulating the Bacillus sulfide into a saturated boric acid solution of calcium chloride for cross-linking, and then washing with sterile saline to obtain the immobilized microbial agent.

4. The preparation method according to claim 3, characterized in that: In step (1), the OD of the concentrated bacterial suspension is 600 The value is 2.0~2.

5.

5. The preparation method according to claim 3, characterized in that: In step (2), the first mixed solution contains 1 wt% to 3 wt% polyvinyl alcohol and 1 wt% to 3 wt% sodium alginate.

6. The preparation method according to claim 5, characterized in that: In step (2), the first mixed solution contains 3wt% polyvinyl alcohol and 1wt% sodium alginate, or the first mixed solution contains 2wt% polyvinyl alcohol and 1wt% sodium alginate, or the first mixed solution contains 1wt% polyvinyl alcohol and 1wt% sodium alginate, or the first mixed solution contains 1wt% polyvinyl alcohol and 2wt% sodium alginate, or the first mixed solution contains 1wt% polyvinyl alcohol and 3wt% sodium alginate.

7. The preparation method according to claim 3, characterized in that: In step (2), the volume ratio of the first mixed solution to the concentrated bacterial suspension is 100:(10-50).

8. The preparation method according to claim 3, characterized in that: In step (3), the bamboo charcoal is added to the second mixed solution at a concentration of 30 g / L to 60 g / L.

9. The preparation method according to claim 3, characterized in that: In step (3), the particle size of the bamboo charcoal is 5 to 10 mm, and the specific surface area is not less than 280 m 2 / g, the apparent density is not less than 0.32g / mL, the strength is not less than 99%, and the micropore ratio is not less than 85%.

10. The preparation method according to claim 3, characterized in that: In step (4), the bamboo charcoal wrapped with Bacillus sulfide is added to a saturated boric acid solution of 1wt% to 5wt% calcium chloride at 3 to 10°C for cross-linking; wherein the cross-linking time is 6 hours to 48 hours.

11. The preparation method according to claim 10, characterized in that: The cross-linking time was 24 hours.

12. Use of the Bacillus sulfide according to claim 1 or the immobilized microbial agent according to claim 2 in degrading malodorous pollutants.

13. A biotrickling filter, characterized in that: The filler of the biotrickling filter contains the Bacillus sulfidus described in claim 1 or the immobilized microbial agent described in claim 2.

14. The biotrickling filter according to claim 13, characterized in that: The filler of the biological trickling filter contains 30% to 60% of the immobilized microbial agent based on the total volume of the filler.

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