CN107760751B

CN107760751B - Preparation of rice peptone for rapidly culturing staphylococcus aureus

Info

Publication number: CN107760751B
Application number: CN201711275414.5A
Authority: CN
Inventors: 田亚平; 龙婧
Original assignee: Jiangnan University (rugao) Food Biotechnology Research Institute; Jiangnan University
Current assignee: Jiangnan University (rugao) Food Biotechnology Research Institute; Jiangnan University
Priority date: 2017-12-06
Filing date: 2017-12-06
Publication date: 2020-08-04
Anticipated expiration: 2037-12-06
Also published as: CN107760751A; WO2019109539A1

Abstract

The invention discloses a preparation method of rice peptone for rapidly culturing staphylococcus aureus, belonging to the technical field of enzyme preparation application. The invention adds rice protein into water, adds alkaline protease, aminopeptidase and neutral protease for enzymolysis, and obtains rice peptone by freeze-drying the enzymolysis product, wherein the rice peptone not only promotes the growth of staphylococcus aureus, but also can be used as a nitrogen source of other microorganisms. The rice peptone can be compounded with other kinds of peptone simultaneously, so that the effect of taking a single peptone as a nitrogen source is improved.

Description

Preparation of rice peptone for rapidly culturing staphylococcus aureus

Technical Field

The invention relates to preparation of rice peptone for rapidly culturing staphylococcus aureus, belonging to the technical field of enzyme preparations.

Background

The novel peptone is added into the original peptone variety to provide specific peptone for different culture medium raw materials, the rice protein is plant protein and has much similar value with soybean protein, namely the rice protein has the same value as the soybean peptone, and the rice with poor quality can be utilized. And the nitrogen source exists in various culture media, such as common culture media, detection culture media, fermentation culture media and the like, the rice peptone not only can be used as one of the components of the culture media, but also can be compounded with other peptones to improve the application value of the original peptone, and has important academic and application significance in related industries.

Staphylococcus aureus (Staphylococcus aureus) is a gram-positive bacterium that is facultative anaerobic, one of the most common and food-borne pathogens of nosocomial infections. Aureus toxins and virulence proteases normally circulate in host blood vessels leading to life-threatening diseases, pathogens often grow in open wounds and the urethra, ranging from mild skin infections to life-threatening diseases such as abscesses, pneumonia, meningitis, endocarditis and septicaemia. Staphylococcus aureus can live in a severe environment and easily contaminate frozen food, water and other articles, and the food poisoning caused by staphylococcus aureus accounts for a large proportion in every country, thus becoming a worldwide public health problem. Therefore, the detection time is shortened as much as possible, and the staphylococcus aureus can be detected and identified as early as possible, so that the method has important significance for monitoring and controlling public health and food safety. The existing detection method usually carries out enrichment culture on the cultured staphylococcus aureus so as to facilitate accurate qualitative and quantitative analysis.

Disclosure of Invention

In order to solve the problem of long detection period in the prior art, the first object of the invention is to provide rice peptone for rapidly culturing staphylococcus aureus or escherichia coli, which is prepared by adding alkaline protease, aminopeptidase and neutral protease into a solution containing rice protein for enzymolysis, and freeze-drying the solution after enzymolysis into powder as a culture medium component for culturing the staphylococcus aureus or the escherichia coli.

In one embodiment of the invention, the culture medium further contains NaCl and beef extract.

In one embodiment of the invention, the content of the rice peptone, NaCl and beef extract in the culture medium is 10 g/L, 5 g/L and 3 g/L.

In one embodiment of the invention, alkaline protease is added in the enzymolysis according to the enzyme adding amount of 4000-8000U/g rice protein; adding aminopeptidase according to the enzyme adding amount of 100-500U/g rice protein; adding neutral protease according to the enzyme adding amount of 3000-4000U/g rice protein.

In one embodiment of the invention, the enzymolysis is carried out on a rice protein solution with the concentration of 60-120 g/L.

In one embodiment of the invention, the addition amount of the alkaline protease is 4000-8000U/g of rice protein.

In one embodiment of the invention, the amount of aminopeptidase added is 100 to 500U/g rice protein.

In one embodiment of the invention, the addition amount of the neutral protease is 3000-4000U/g rice protein.

In one embodiment of the present invention, the enzymatic hydrolysis is performed at 35 ℃ to 40 ℃.

In one embodiment of the invention, the enzymolysis time is 1-6 hours.

In one embodiment of the present invention, the enzymatic hydrolysis pH is 6.5 to 8.0.

In one embodiment of the invention, the cultured staphylococcus aureus is activated before culture, and the activation medium L B comprises peptone 10 g/L, yeast powder 5 g/L and sodium chloride 10 g/L.

In one embodiment of the invention, the culturing is carried out at 36-38 ℃ for 24-29 h.

In one embodiment of the invention, the concentration of the rice protein is 80 g/L, the adding amount of alkaline protease is 8000U/g substrate, the adding amount of aminopeptidase is 500U/g substrate, the adding amount of neutral protease is 3000U/g substrate, the reaction temperature is 35 ℃, the pH value is 7.5, and the reaction time is 2 h.

The second purpose of the invention is to provide a new peptone, which is treated by alkaline protease, aminopeptidase and protease enzymolysis.

In one embodiment of the invention, the enzymolysis time is 1-6 hours.

In one embodiment of the invention, the content of peptone, NaCl and beef extract in the culture medium is 10 g/L, 5 g/L and 3 g/L.

The third purpose of the invention is to provide a compound of rice peptone and other types of peptone.

In one embodiment of the invention, rice peptone and homemade tryptone are compounded in different mass ratios as follows: 1:2 to 1:5 (mass of tryptone: mass of rice protein) and 1:1 to 5:1 (mass of tryptone: mass of rice protein).

In one embodiment of the invention, rice peptone is compounded with commercially available domestic peptone, fish peptone, import peptone and tryptone in a mass ratio of 1: 3.

In one embodiment of the invention, the content of the composite peptone, NaCl and beef extract in the culture medium is 10 g/L, 5 g/L and 3 g/L.

The invention also provides application of the peptone in food-borne pathogenic bacteria detection and microorganism culture in the fields of food and medicine.

In one embodiment of the invention, the method comprises the use of rice peptone, rice peptone.

The invention has the beneficial effects that:

1. the invention provides an enzymolysis optimization strategy of rice peptone for rapidly culturing staphylococcus aureus, thereby promoting the growth of staphylococcus aureus, wherein the peptide of the rice protein subjected to enzymolysis treatment is mainly less than 3000Da and accounts for 99.28% of all peptides, so that the obtained peptone is mainly formed by mixing polypeptide molecules of 3000-200 Da, the amino acids in the rice protein enzymolysis solution are not only various, but also the essential amino acids account for 58.48% of the total amino acids, and the non-essential amino acids account for 41.52%, so that microorganisms can fully utilize the required amino acids to grow and propagate in the growth metabolism, and the total content of branched chain amino acids of valine (Val), isoleucine (Ile) and leucine (L eu) in a plurality of amino acids is 32.56%, while the total content of aromatic amino acids of tryptophan (Trp), phenylalanine (Phe) and tyrosine (Tyr) is 20.07%, and the partial branched chain amino acids are beneficial to promoting the rapid growth and propagation of staphylococcus aureus.

2. The rice peptone can be used for culturing not only staphylococcus aureus but also various other microorganisms.

3. The rice peptone is compounded with the peptone sold in the market in a mass ratio of 1:3, so that the application value of single peptone is favorably improved.

Drawings

FIG. 1 is a schematic view of a process for enzymatic hydrolysis of rice protein;

FIG. 2 is a graph showing the effect of different enzymatic hydrolysis times and different enzyme products on the growth of Staphylococcus aureus;

FIG. 3 is a graph showing the effect of different enzyme dosages of alkaline protease on the growth of Staphylococcus aureus;

FIG. 4 is a graph showing the effect of varying amounts of aminopeptidase added product on the growth of Staphylococcus aureus;

FIG. 5 is a graph showing the effect of different enzyme dosages of the product of neutral protease on the growth of Staphylococcus aureus;

FIG. 6 is a graph showing the effect of different pH of enzymatic products on the growth of Staphylococcus aureus

FIG. 7 is a graph showing the effect of products of different enzymatic temperatures on the growth of Staphylococcus aureus;

FIG. 8 is a graph of the effect of enzymatic products of different substrate concentrations on the growth of Staphylococcus aureus;

FIG. 9 is a graph showing the growth of Staphylococcus aureus on different peptones;

FIG. 10 is a graph showing growth curves of Escherichia coli cultured on different peptones;

FIG. 11 is a graph showing the growth of Bacillus subtilis cultured with different peptones;

FIG. 12 shows the effect of different quality of rice peptone and self-made tryptone on the growth of Staphylococcus aureus;

FIG. 13 shows the effect of rice peptone on commercially available peptone pairing Staphylococcus aureus at a mass ratio of 1: 3.

Detailed Description

Example 1

(1) And (2) performing enzymolysis on the rice protein, namely preparing a rice protein solution with the concentration of 60-120 g/L, adding alkaline protease with the enzyme amount of 4000-8000U/g of the rice protein, adding aminopeptidase with the enzyme amount of 100-500U/g of the rice protein, adding neutral protease with the enzyme amount of 3000-4000U/g of the rice protein, reacting at the temperature of 35 ℃, keeping the pH value at 7.5, reacting for 2 hours, and performing freeze-drying treatment on the enzymolysis liquid after reaction to obtain the rice peptone.

(2) The lyophilization procedure is shown in table 1 below:

centrifuging the liquid after enzymolysis to retain supernatant, subpackaging the supernatant into centrifuge tubes of 50m L, placing into a refrigerator at the temperature of-20 ℃ for pre-freezing for 12h, then placing into a refrigerator at the temperature of-80 ℃ for pre-freezing for 12h, placing into a tray of a vacuum freeze dryer, and freeze-drying according to the procedures in Table 1.

(3) A nutrient broth liquid culture medium was prepared, which contained 1000m L parts of ultrapure water, 10g of peptone, 3g of beef extract, and 5g of NaCl, as prepared in this example.

(4) Activating commercial staphylococcus aureus in L B culture medium, culturing activated staphylococcus aureus in L B liquid culture medium for 16-18 hr, diluting bacterial liquid with sterilized deionized water 10⁴Taking 100 mu L diluent from the rice peptone to the liquid culture medium with the composition, carrying out shake culture at 37 ℃ and 220r/min for 24 hours or 28 hours, respectively taking 2m L bacterial liquid from each shake flask, taking the corresponding culture medium without the bacterial liquid as a blank control, and measuring an OD value by using a spectrophotometer under the condition that the wavelength is 600nm, wherein the higher the OD value is, the more obvious promotion effect of the rice peptone obtained under the enzymolysis condition on staphylococcus aureus is shown.

Example 2

The same procedure as in example 1 was followed, except that the enzymatic hydrolysis was carried out with alkaline protease and trypsin for 1, 2, 3, 4, 5 and 6 hours, respectively, and the enzyme amounts were the sameIs 12000 U.g^-1。

The results are shown in FIG. 2:

the enzymolysis of the rice milt by the alkaline protease has the trend that the OD value of the cultured staphylococcus aureus is increased after being increased along with the change of time, and is the maximum value when the enzymolysis time is 2 hours.

When rice protein is subjected to enzymolysis by pancreatin, the OD value is in a state of continuously rising along with the change of time, the OD values in the two stages are not greatly changed respectively when the enzymolysis time is 2-3 h and 4-6 h, and after the time is 4h, the OD values are basically consistent, so that the substrates are possibly subjected to enzymolysis fully, the components are not changed along with the extension of the enzymolysis time, and the effects of culturing the strains by using the products in the time period are almost consistent.

The effect of the products of the alkaline protease and the trypsin on the strains is consistent in trend and gradually increases when the rice protein is subjected to enzymolysis for 2 hours before enzymolysis, and the effect of the products of the alkaline protease and the trypsin on the growth of staphylococcus aureus is more favorable. After 2h, however, the growth effect of the alkaline protease on the strain shows a V-shaped change, the growth effect of the trypsin shows a ladder type, and the effect of the alkaline protease is higher than that of the enzymolysis product of the trypsin. Considering comprehensively, alkaline protease is selected as one of enzymes for enzymolysis, and the time is selected to be 2 h.

Example 3

The same procedure as in example 1 was conducted except that alkaline protease alone was added in amounts of 4000 U.g., respectively^-1、6000U·g^-1、8000U·g^-1、10000U·g^-1、12000U·g^-1、14000U·g^-1、16000U·g^-1Enzymolysis is carried out for 2h, the substrate concentration is 10%, the pH is 8.5, and the temperature is 50 ℃.

As shown in FIG. 3, the growth of Staphylococcus aureus cultured with the products of enzymolysis of rice albumin by different alkaline proteases was inconsistent, when the enzyme was added in an amount of less than 8000 U.g^-1When the enzyme amount is more than 8000 U.g, the OD value of staphylococcus aureus is gradually increased, which shows that the effect of enzymolysis product on the growth of bacterial strain is gradually increased, and when the enzyme amount is more than 8000 U.g^-1When it comes toThe OD value becomes smaller gradually by adding the enzyme, and the growth promoting effect of the product on the strain is reduced with the increase of the enzyme amount, and when the adding amount is 8000U g^-1The maximum OD is the one that indicates the product under the conditions of this enzymatic hydrolysis, which is most favorable for its growth. Possibly the product component at the moment, is convenient for the strains to absorb and utilize so as to be convenient for the strains to rapidly grow and reproduce. Therefore, 8000U g is selected^-1The amount of enzyme added for enzymolysis of rice protein as alkaline protease.

Example 4

The same procedure as in example 1 was conducted, except that the amount of alkaline protease used was 8000 U.g^-1The enzymolysis time is 2h, and the dosage of aminopeptidase is 100 U.g^-1、200U·g^-1、300U·g^-1、400U·g^-1、500U·g^-1、600U·g^-1。

As a result, as shown in FIG. 4, when the amount of addition is less than 300 U.g^-1The OD value of the cultured Staphylococcus aureus was almost unchanged, and when the amount was 400 Ug/g^-1The OD value was minimum, and when the enzyme was added in an amount of 500 U.g^-1The OD is at its maximum and the product obtained in this amount is most beneficial for the growth of the strain, probably because the components under these conditions play a critical role in the growth of the strain.

Example 5

The same procedure as in example 1 was conducted, except that the amount of alkaline protease used was 8000 U.g^-1The aminopeptidase is used in an amount of 500 U.g^-1The dosage of neutral protease is 1000U g^-1、2000U·g^-1、3000U·g^-1、4000U·g^-1、5000U·g^-1。

As shown in FIG. 5, the addition of neutral protease makes the corresponding product more beneficial to the growth of Staphylococcus aureus, and the OD value increases and then decreases with the increase of neutral protease, when the amount of the added enzyme is 3000 U.g^-1When the OD value is maximum, the dosage is 3000 U.g^-1. Alkaline protease, neutral protease and aminopeptidase are selected for compound enzymolysis, so that the enzymolysis product of the rice protein is beneficial to golden yellow glucanGrowth of staphylococci.

Example 6

The procedure is as in example 1, except that 5mol L is used^-1And 0.5mol · L^-1The pH of the mixture was adjusted to 6.5, 7.0, 7.5, 8.0, 8.5 and 9.0 during the enzymatic hydrolysis.

As shown in fig. 6, the OD value shows a trend of decreasing with the increase of pH, but when pH is 7.5, the OD value is the largest, and when pH is 9.0, the OD value obtained by the zymolysis product culture strain under the condition is the smallest, probably because when pH is 9.0, neutral protease is preferably pH range of 6.0-8.0, the activity of neutral protease is affected, the zymolysis effect is weakened, so that the components of the product obtained by zymolysis of rice protein are changed and deviate from the components suitable for the growth of staphylococcus aureus.

Example 7

The same procedure as in example 1 was carried out except that the enzymatic hydrolysis temperatures were 35 deg.C, 40 deg.C, 45 deg.C, 50 deg.C and 55 deg.C, respectively.

As shown in fig. 7, when the enzymolysis temperature is lower than 45 ℃, the growth promoting effect of the product of enzymolysis at the corresponding temperature on staphylococcus aureus gradually decreases with the increase of the temperature, and when the temperature is higher than 45 ℃, the OD value increases first and then decreases with the increase of the temperature, which indicates that the efficiency of utilizing the product under the corresponding condition by the strain becomes low, so that the growth becomes slow. The OD value obtained by culturing the strain under these conditions was the largest when the temperature was 35 ℃. Therefore, 35 ℃ was selected as the next enzymatic temperature.

Example 8

The same procedure as in example 1 was followed, except that the substrate concentrations were 4%, 6%, 8%, 10% and 12%, respectively. As shown in FIG. 8, the OD value was between 4% and 8% with the increase of the substrate concentration, increased with the increase of the substrate concentration, and decreased with the increase of the substrate concentration when the substrate concentration was between 8% and 12%. At a substrate concentration of 8%, the OD reached a maximum value, indicating that the product under these conditions was most beneficial for the growth of Staphylococcus aureus.

Example 9

Accurately weighing 5.6g of rice protein, preparing rice protein solution with substrate concentration of 8% at 70m L, maintaining enzymolysis temperature at 35 ℃ by using a constant-temperature magnetic stirrer, adding 0.310m L enzyme powder (enzyme activity is 14.6 ten thousand U/m L) into the rice protein solution according to the dosage ratio of alkaline protease to substrate of 8000U/g, adding 0.611g of enzyme powder (enzyme activity is 4580U/g) into the rice protein solution according to the dosage ratio of aminopeptidase to substrate of 500U/g, adding 0.1018g of enzyme powder (enzyme activity is 16 ten thousand U/g) into the rice protein solution, dropwise adding 0.5 mol/L NaOH into the rice protein solution to adjust pH, maintaining pH at 7.5, carrying out enzymolysis for 2h, centrifuging the enzyme hydrolysate at 12000rpm for 10min, taking supernatant liquid at 2m L to measure polypeptide molecular weight distribution of the enzymolysis solution, taking supernatant liquid at 3m, adding equal volume of 10% TCA L to adjust pH, standing for 2h, taking supernatant liquid at 10000 h, centrifuging the supernatant liquid at 3910 m, taking free amino acid content of the polypeptide, and taking free amino acid content of the supernatant liquid at 39u and centrifuging the molecular weight of 10 μm.

The polypeptide molecular weight distribution (table 2) results show: the peptides subjected to enzymolysis treatment are mainly smaller than 3000Da and account for 99.28% of all peptides, so that the obtained peptone is mainly formed by mixing polypeptide molecules of 3000-200 Da, and the growth of staphylococcus aureus is promoted mainly by the peptone.

TABLE 2 molecular weight of rice peptone

Amino acid analysis (table 3) the rice protein hydrolysate contains various amino acids, wherein the essential amino acid accounts for 58.48 percent of the total amino acids, the non-essential amino acid accounts for 41.52 percent of the total amino acids, so that the microorganisms can fully utilize the required amino acids in the growth metabolism to carry out growth and propagation, the total content of branched-chain amino acids of valine (Val), isoleucine (Ile) and leucine (L eu) in a plurality of amino acids is 32.56 percent, the total content of aromatic amino acids of tryptophan (Trp), phenylalanine (Phe) and tyrosine (Tyr) is 20.07 percent, and the partial number of the branched-chain amino acids is beneficial to promoting the rapid growth and propagation of staphylococcus aureus.

TABLE 3 amino acid composition and content

Example 10

The method comprises the steps of preparing a nutrient medium from rice protein peptide according to the components of the nutrient medium, measuring the growth curve of staphylococcus aureus, escherichia coli and bacillus subtilis by using 2 commercially available peptone and fish peptone, culturing the activated bacteria in L B culture medium for 16-18 h respectively, sucking the activated bacteria into a corresponding liquid culture medium according to the inoculation amount of 0.5%, carrying out shake culture at 37 ℃ and 220r/min for 24h, taking samples from a shake flask every 2h, measuring OD (origin-to-destination) and measuring the growth curve of the bacteria₆₀₀The growth promoting effect of the rice peptone on staphylococcus aureus and the feasibility of the rice peptone on other microorganisms are examined.

The results (FIGS. 9 to 11) show that: as can be obtained from FIG. 9, the growth trends of the Staphylococcus aureus cultured by the 4 raw materials are basically consistent, the delay period is about 6h, and the difference between the strains cultured by the 4 raw materials is gradually enlarged along with the continuous change of the culture time, wherein the OD value of the Staphylococcus aureus cultured by the rice peptone is the maximum value no matter in the logarithmic phase or the stationary phase, and the difference is very obvious. The biomass present is also the largest available. The growth promotion effect of the rice peptone on staphylococcus aureus is the most obvious, the tryptone 1 is added, the tryptone 2 is added, and the effects of the 2 tryptones on the microorganism are different, wherein the effect of the tryptone is better than that of the tryptone 1, and the differences of the tryptones produced by different manufacturers are shown. The peptone is the worst peptone, which indicates that the growth promoting effect of the fish peptone on staphylococcus aureus is the weakest.

It can be seen from fig. 10 that there is no lag phase of escherichia coli, and the adaptability is strong, wherein the OD value of the growth curve of rice peptone culture is higher than that of the other 3 in both growth phase and stationary phase, which indicates that the growth effect of rice peptone on escherichia coli is most beneficial, and the OD value of the microorganism is basically consistent when tryptone and fish peptone are in logarithmic phase, but the culture effect of tryptone 1 is better than that of fish peptone, and the OD value of fish peptone and the OD value of tryptone 2 are different in logarithmic phase, but the difference is reduced and finally tends to be consistent with the extension of culture time.

As can be seen from FIG. 11, the growth curves for 4 materials against Bacillus subtilis are different, in which the times appearing from the high points are different, among which tryptone 2, which is more prominent, has a logarithmic phase substantially identical to that of rice peptone, but the stationary phase of this bacterium cultured with tryptone 2 is longer than that of rice peptone, which has substantially no stationary phase. The OD value of the bacillus subtilis cultured by the tryptone 1 is higher than that of the fish peptone at the end of a logarithmic phase and a stationary phase, which shows that the culturing effect of the tryptone 1 is better than that of the fish peptone. The growth curve of the rice peptone culture microorganism is different from that of other 3 kinds of microorganisms, has no stationary phase, but has a highest point which is basically close to that of the tryptone 2, and the culture promoting effect of the rice peptone on the microorganism is also more advantageous.

The rice peptone can be used for culturing microorganisms which are commonly used and detected, and can be obtained from tryptone and fish peptone which are commonly used in the market, the advantage of the rice peptone on the growth promotion effect of the microorganisms is higher than that of other 3 peptones, particularly the growth promotion effect on the two microorganisms of culturing microorganisms staphylococcus aureus and escherichia coli is particularly obvious, the rice peptone can be added or replaced to be used for culturing and detecting pathogenic bacteria staphylococcus aureus, and the purpose of shortening the detection time is achieved in food sanitation safety and medical microorganism detection. In terms of production, the desired biomass can be achieved in a short time. Rice peptone is feasible as one of the culture components of microorganisms.

Example 11

Compounding self-made tryptone and rice peptone according to a mass ratio, wherein the formula comprises 10 g/L of compound peptone, 3 g/L of beef extract powder and chloridizationSodium 5 g/L, preparing culture medium, shake culturing at 37 deg.C and 220r/min, respectively culturing for 24 hr, sampling, and measuring OD₆₀₀The results are shown in FIG. 12. The abscissa represents the peptone for each set of experiments according to tryptone: the rice peptone is 1:2, 1:3, 1:4, 1:5, 1:1, 2:1, 3:1, 4:1, 5:1, 1:0 and 0:1 in mass, and the OD value of the compound culture medium is generally more favorable than that of the compound culture medium for culturing the staphylococcus aureus by using two single peptones, and the growth promoting effect is achieved. Wherein the mass ratio of 1:2 to 1:5 is that the mass of the rice peptone is gradually increased, and the OD value presents an inverse ratio and is reduced along with the increase of the rice peptone; wherein, 1:1 to 5:1 means that the mass of the rice peptone is gradually reduced, the mass of the tryptone is gradually increased, the OD value is increased along with the mass of the tryptone, and the growth promoting effect is also increased along with the increase of the mass of the tryptone. According to the compounding ratio, when the proportion of the tryptone is higher than that of the rice peptone, the growth promoting effect is higher than that of the tryptone. When the mass ratio of the tryptone to the rice peptone is 3:1, the OD value is the largest, which shows that the growth promoting effect on staphylococcus aureus is the best.

Example 12

Respectively compounding rice peptone with domestic peptone, fish peptone, import peptone and tryptone in a mass ratio of 1:3, culturing staphylococcus aureus, and comparing with independent culture, activating the staphylococcus aureus on L B culture medium, respectively culturing the activated bacteria in L B culture medium for 16-18 h, and diluting the bacterial liquid by 10⁴Then 100u L are taken from the culture medium and cultured in a shaking way at 37 ℃ and 220r/min for 24h, the sampling is carried out, and the OD is measured₆₀₀The results are shown in FIG. 13. When the peptone and the rice peptone are used in a composite way, the OD value is a group of lines with squares, and when the peptone is used independently, the OD value is a group of lines with circles, so that the growth promotion effect of the composite peptone is higher than that of the single peptone. The rice peptone can be used for improving the growth promoting effect of the peptone on microorganisms, can be used as one of compound components, can improve the peptone with nitrogen source component difference, and is beneficial to increasing the variety and effect improvement of the peptone.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The preparation method of the rice peptone for rapidly culturing staphylococcus aureus is characterized in that alkaline protease, aminopeptidase and neutral protease are added into a rice protein solution for enzymolysis, the solution after enzymolysis is freeze-dried to be powder and used as a culture medium component to culture staphylococcus aureus, the alkaline protease is added according to the enzyme adding amount of 4000-8000U/g of rice protein for enzymolysis, the aminopeptidase is added according to the enzyme adding amount of 500U/g of rice protein, the neutral protease is added according to the enzyme adding amount of 3000-4000U/g of rice protein, the concentration of an enzymolysis substrate rice protein solution is 8%, the enzymolysis temperature is 35 ℃, and the enzymolysis time is 2 hours.

2. The method of claim 1, wherein the culture medium further comprises NaCl and beef extract.

3. The method of claim 2, wherein the rice peptone, NaCl and beef extract are contained in the medium in an amount of 10 g/L, 5 g/L, 3 g/L.

4. The method according to any one of claims 1 or 3, wherein the enzymatic hydrolysis is carried out at a pH of 6.5 to 8.0.

5. Rice peptone, which is produced by the method according to any one of claims 1 to 4.

6. The rice peptone according to claim 5, characterized in that the enzymatic hydrolysis is carried out at 35 ℃, the enzymatic hydrolysis time is 2h, and the enzymatic hydrolysis pH is 6.5-8.0.

7. Use of rice peptone as claimed in claim 5 or 6 for food and culture of microorganisms.

8. Use according to claim 7, characterized in that it is used in combination with other peptones.