Disclosure of Invention
In order to make up the defects of the prior art, the invention provides a composite microbial inoculum for water quality purification. The composite microbial inoculum can effectively reduce the content of nitrogen-containing compounds such as ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and the like in the aquaculture water body, which influence the water quality, and improve the water quality of the aquaculture water body.
The invention adopts the following technical scheme: the composite bacterial agent for purifying water quality is composite bacterial suspension comprising 8% of lactobacillus plantarum and bacillus caldovelox in the ratio of 2: 1.
The lactobacillus plantarum and bacillus caldovelox bacterial suspension is prepared according to the following steps:
s1. activating strains
Preparing LB and MRS solid culture media, making into an inclined plane and a flat plate, respectively scribing the plant lactobacillus strain and the Bacillus caldus strain on the inclined plane by using bamboo sticks, culturing at 30 ℃, and after 3-7 d of culture, storing at 4 ℃ for later use;
s2. propagation of strains
Respectively picking the activated plant lactobacillus strain and the activated bacillus calsius strain by using bamboo sticks, inoculating the plant lactobacillus strain and the activated bacillus calsius strain into LB or MRS liquid culture medium according to the inoculation amount of 8 percent, and performing shake cultivation at the constant temperature of 30 ℃ for 24 hours to obtain the plant lactobacillus strain and the activated bacillus calsius strain;
s3, preparation of bacterial suspension
Pouring Lactobacillus plantarum suspension and Bacillus Simsii suspension into a centrifuge tube at a ratio of 2:1, centrifuging at 10000r/min for 10min, mixing with sterile water, making into suspension, and counting live bacteria with microscope to obtain live bacteria with a count of 109cfu/mL。
The lactobacillus plantarum strain and the bacillus caldovelox strain in step S1 were stored at-80 ℃.
The LB medium (g/L): 10.0g of peptone, 10.0g of sodium chloride and 5.0g of yeast extract. The pH before sterilization was 7.2.
The MRS medium (g/L): 10.0g of beef extract, 5.0g of yeast extract,peptone 10.0g, glucose 20.0g, K2HPO42.0g,K2HPO45.0g,MgSO4·7H2O0.2g,MnSO4·4H2O0.05g, Tween 801.0g and triammonium citrate 2.0 g. The pH value before sterilization is 6.2-6.6.
The invention also provides application of the composite microbial inoculum in water quality purification. The composite microbial inoculum is added into the water body to be purified, the degradation rate of ammonia nitrogen salt in the water is highest in the 7 th day, the degradation rate of nitrite nitrogen is highest in the 3 rd day, and the degradation rate of nitrate nitrogen in the water is highest in the 10 th day.
The composite microbial inoculum is prepared by taking the ratio of lactobacillus plantarum to bacillus caldovelox as 2:1, and has the optimal degradation effect. When the inoculation amount is 8%, the degradation rate of ammonia nitrogen salt is 88.57%, the degradation rate of nitrite nitrogen is 97.87%, and the degradation rate of nitrate nitrogen is 92.37%, so that the content of pollution factors such as ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in aquaculture can be obviously reduced. Effectively improves the culture environment and reduces the resource waste.
Detailed Description
The invention is described in more detail below with reference to specific examples, without limiting the scope of the invention. Unless otherwise specified, the experimental methods adopted by the invention are all conventional methods, and experimental equipment, materials, reagents and the like used in the experimental method can be purchased from chemical companies.
In the following examples, P1 represents lactobacillus plantarum; s1 represents Bacillus caldovelox. The strain is commercially available. The Bacillus siemens (Bacillus siamensis) is purchased from China agricultural microbial strain preservation management center with the preservation number of ACCC 06497. Lactobacillus plantarum (Lactobacillus plantarum) is purchased from China general microbiological culture collection center with the collection number of CGMCC 1.568.
In the following examples, the specific method for simulating the design of the water environment is as follows:
taking sewage which is used for culturing fancy carp for one week, and adding 150mL of sewage into each triangular flask. 0.1g of fancy carp feed is added into every 150mL of sewage. This is a simulated water environment.
Each salt content control group is compared with a simulated water environment without inoculation.
Example 1
(1) Activated strain
Preparing LB and MRS solid culture media, making into an inclined plane and a flat plate, taking out the glycerol tubes of experimental strains of lactobacillus plantarum and bacillus Simsii from a refrigerator at minus 80 ℃, naturally thawing, drawing lines on the inclined plane by using bamboo sticks, culturing at 30 ℃, and after 3-7 days of culture, storing in the refrigerator at 4 ℃ for later use.
(2) Propagation strain
Picking the activated experimental strain by using a bamboo stick, inoculating the experimental strain into an LB or MRS liquid culture medium according to the inoculation amount of 8%, and performing shaking culture at the constant temperature of 30 ℃ for 24 hours to obtain a plant lactobacillus strain and a bacillus caldus solution;
(3) preparation of the bacterial suspension
Pouring Lactobacillus plantarum suspension and Bacillus Simsii suspension into a centrifuge tube at a ratio of 2:1, centrifuging at 10000r/min for 10min, mixing with sterile water, making into suspension, and counting live bacteria with microscope to obtain live bacteria with a count of 109cfu/mL。
Example 2
The difference between the embodiment and the embodiment 1 is that lactobacillus plantarum and bacillus caldovelox are uniformly mixed according to the proportion of 1:1 to prepare a complex microbial inoculum suspension.
Example 3
The difference between the embodiment and the embodiment 1 is that lactobacillus plantarum and bacillus caldovelox are uniformly mixed according to the proportion of 1:2 to prepare a complex microbial inoculum suspension.
Example 4 measurement of influence of inoculum size and Complex microbial inoculum blend ratio on degradation Rate of Ammonia Nitrogen salt (Nashin reagent photometer method)
(1) Determination of the Standard Curve
a. Sucking 0,50,100,300,500,700 and 1000 μ L of standard ammonium use solution into a test tube, adding double distilled water to 5mL, and mixing uniformly;
b. sequentially adding 100 mu L of potassium sodium tartrate and 150 mu L of the Nashi reagent, and uniformly mixing;
c. standing for 10min, measuring absorbance at a wavelength of 420nm (glass cuvette), and zeroing with double distilled water as a blank.
(2) Sample assay
a. Taking 5mL of water sample, sequentially adding 100 mu L of potassium sodium tartrate and 150 mu L of the Nashi reagent, and uniformly mixing;
b. standing for 10min, measuring absorbance at wavelength of 420nm (glass cuvette), and zeroing with double distilled water as blank (adding reagent)
c. And obtaining the content of ammonia nitrogen in the sample according to the corresponding amount in the absorbance.
The salt concentration in the water environment of the daily simulated aquaculture is recorded, and as the water is changed every week during the fishery aquaculture, in order to compare the influence of different inoculation amounts on the degradation rate of ammonia nitrogen salt, the degradation rate of the seventh day is adopted as a comparison group in the following experiments, and the results are shown in table 1:
TABLE 1 degradation ratio (%)
The results in table 1 show that the degradation rate of the ammonia nitrogen salt is 53.97% -88.57% in the 8% inoculation amount, and the degradation rates of the 3% inoculation amount and the 5% inoculation amount are 17.56% -41.65% and-8.13% -44.70% respectively, so that the degradation effect of the 8% inoculation amount is better than that of other inoculation amounts.
On the basis of selecting the optimal inoculation amount of 8%, the influence of the composite microbial inoculum with different proportions on the degradation efficiency of the ammonia nitrogen salt is compared, the concentration of the ammonia nitrogen salt in the daily simulated aquaculture water environment is recorded, the result is shown in figure 1, and the result is shown in figure 1 and is shown by the continuous 10-day measurement result. The degradation efficiency of the compound microbial inoculum P1: S1 is 2:1 to the ammonia nitrogen salt is better than that of the compound microbial inoculum with other mixture ratios, the degradation effect is better than that of a single microbial inoculum, and the highest degradation rate (88.57%) is reached at 10 d.
EXAMPLE 5 Effect of inoculum size and Complex microbial inoculum proportioning on nitrite Nitrogen degradation Rate (N- (1-naphthyl) -Ethylenediamine photometry)
(1) Determination of the Standard Curve
a. Sucking 0,50,100,300,500,700 and 1000 mu L of nitrite nitrogen standard use solution into a test tube, adding double distilled water to 5mL, and uniformly mixing;
b. adding 100 mu L of nitrite color developing agent, and mixing uniformly;
c. standing for 20min, measuring absorbance at a wavelength of 540nm (glass cuvette), and zeroing with distilled water as a blank (adding reagent).
(2) Sample assay
a. Adding 100 mu L of nitrite color developing agent into 5mL of sample, and uniformly mixing;
b. standing for 20min, measuring absorbance at wavelength of 540nm (glass cuvette), and zeroing with distilled water as blank (adding reagent);
c. the corresponding amount in the absorbance gives the nitrite content of the sample.
TABLE 2 degradation ratio of nitrite nitrogen (%)
As can be seen from Table 2, the effect of the complex microbial inoculum with high inoculum size (8%) on the degradation rate of nitrite nitrogen is obviously better than that of the complex microbial inoculum with low inoculum size, and is also better than that of a single bacterial strain, and the effect of the degradation rate of Bacillus siemens with high inoculum size is also better than that of Lactobacillus plantarum of the single bacterial strain.
As can be seen from FIG. 2, the degradation rates of single strains and complex microbial inoculum on nitrite nitrogen are not obviously different from the first 2-7 days, but are in the 7 th-8 th days. The degradation efficiency of the individual strains started to decline. At 8d, it is significantly lower than that of the complex strain, and the ratio of complex strain 2:1 is optimal. Therefore, if the water quality purification effect is kept for a long time, the composite microbial inoculum is adopted, and the degradation efficiency of the composite microbial inoculum shows a stable and lasting effect.
Example 6 measurement of influence of inoculum size and Complex microbial inoculum blend ratio on nitrate Nitrogen degradation Rate (ultraviolet spectrophotometry)
(1) Determination of the Standard Curve
a. Sucking 0, 12.5, 25, 50, 75 and 100 mu L of nitrate nitrogen standard stock solution into a test tube, adding double distilled water to 5mL, and uniformly mixing;
b. adding 100 mu LHCI solution and 10 mu L sulfamic acid solution and mixing evenly;
c. measuring the absorbance at wavelengths of 220nm and 275nm (quartz cuvette); using distilled water as a blank to adjust zero (adding a reagent);
d.A calibration of A220-A275
(2) Sample assay
a. Taking 5mL of water sample, adding 100 mu L of LHCI solution and 10 mu L of sulfamic acid solution, and uniformly mixing;
b. measuring the absorbance at wavelengths of 220nm and 275nm (quartz cuvette); using distilled water as a blank to adjust zero (adding a reagent);
c. and calculating the nitrate nitrogen content of the water sample from the standard curve according to the measured absorbance value.
TABLE 3 degradation ratio of nitrate nitrogen (%)
From the results shown in table 3, it is understood that the effect of the composite microbial inoculum on the degradation rate of nitrate nitrogen is similar to that of nitrite nitrogen, and that the effect of the composite microbial inoculum on the degradation rate of nitrate nitrogen is high (8%).
As can be seen from FIG. 3, the degradation efficiency of nitrate nitrogen by both single strains and complex strains increased with the increase of the culture time. Reaches a maximum at 10d and then remains at a high degradation rate level.
Application example
The simulated aquaculture water environment is taken as a research environment, and the synergistic purification effect of the two microbial agents and the composite microbial agent thereof on the water body is investigated.
And recording the time for observing the salt concentration in the daily simulated aquaculture water environment to reach the optimal degradation rate, wherein the group P1: S12:1 is selected for ammonia nitrogen salt, nitrite nitrogen and nitrate nitrogen. As can be seen from FIG. 4, the degradation rate of the compound microbial inoculum P1: S12:1 on ammonia nitrogen salt reaches the highest degradation rate of 88.57% at the 7 d; as can be seen from FIG. 5, the degradation rate of the compound bacterial agent P1: S12:1 on nitrite nitrogen reaches the highest degradation rate of 97.87% at the 3 rd stage, and then the degradation rate is continuously stabilized at about 95%. As can be seen from FIG. 6, the degradation rate of the complex bacteria to nitrate nitrogen reached a maximum of 92.37% at 10d, but it had stabilized substantially continuously at about 94% after 8 d. Therefore, the lactobacillus plantarum and bacillus caldovelox compound microbial inoculum has a remarkable effect of purifying water quality.
The results of the above examples and application examples show that the degradation effect of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen is superior to that of other inoculation amounts when the inoculation amount is 8%; when the ratio of the lactobacillus plantarum to the bacillus caldovelox is 2:1, the optimal degradation effect is achieved; ammonia nitrogen salt, nitrite nitrogen and nitrate nitrogen reach peak values at 7d, 4d and 10d respectively, and the optimal degradation time can last for 4-7 d; the pH value has no significant difference during the experiment, namely the inoculation microbial inoculum has no obvious influence on the pH value of the water body. Therefore, the composite microbial inoculum prepared by the method can effectively reduce the content of nitrogen-containing compounds such as ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and the like in the aquaculture water body, which influence the water quality, in a certain time, and improve the water quality of the aquaculture water body.
The above description is only for the purpose of creating a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution and the inventive concept of the present invention within the technical scope of the present invention.