阅读说明：本技术 一种利用细菌非生长耦联特性生产β-1,3-葡聚糖的方法 (Method for producing beta-1, 3-glucan by using non-growth coupling characteristic of bacteria ) 是由 袁建国 吉武科 高先岭 于 2020-12-23 设计创作，主要内容包括：本发明涉及微生物发酵技术领域,具体涉及一种利用细菌非生长耦联特性生产β-1,3-葡聚糖的方法。所述方法包括以下步骤：将产β-1,3-葡聚糖菌株进行活化,制备种子培养液；将种子培养液接入发酵培养基中,进行发酵培养；发酵结束后,将60-80%的发酵液转入转化罐内；向剩余20-40%的发酵液中加入发酵培养基至初始发酵体积,再继续进行二次发酵,如此循环5-6次；S4.向转化罐内分次流加糖液,进行全细胞转化。本发明方法通过高密度发酵培养和流加补糖全细胞转化的方式,可以显著提高β-1,3-葡聚糖产量,并缩短生产周期,降低生产成本,解决了现有发酵工艺的不足。(The invention relates to the technical field of microbial fermentation, in particular to a method for producing beta-1, 3-glucan by utilizing the non-growth coupling characteristic of bacteria. The method comprises the following steps: activating the beta-1, 3-glucan producing strain to prepare a seed culture solution; inoculating the seed culture solution into a fermentation culture medium for fermentation culture; after fermentation, transferring 60-80% of fermentation liquor into a conversion tank; adding a fermentation culture medium into the rest 20-40% of the fermentation liquor to the initial fermentation volume, and continuing to perform secondary fermentation, and circulating for 5-6 times; and S4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion. The method can obviously improve the yield of the beta-1, 3-glucan, shorten the production period, reduce the production cost and solve the defects of the existing fermentation process by means of high-density fermentation culture and fed-batch glucose-supplementing whole-cell transformation.)

1. A method for producing beta-1, 3-glucan by utilizing the non-growth coupling property of bacteria, comprising the steps of:

s1, activating a strain producing beta-1, 3-glucan to prepare a seed culture solution;

s2, inoculating the seed culture solution into a fermentation culture medium for fermentation culture;

s3, after fermentation is finished, transferring 60-80% of fermentation liquor into a conversion tank; adding a fermentation culture medium into the rest 20-40% of the fermentation liquor to the initial fermentation volume, continuing to perform secondary fermentation, and transferring 60-80% of the fermentation liquor into a conversion tank after the fermentation is finished; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is 1h after the fermentation liquor is transferred;

the second feeding time is 30-35 hours after the fermentation liquor is transferred;

the third feeding time is 40-45h after the fermentation liquor is converted.

2. The method according to claim 1, wherein the β -1, 3-glucan producing strain is agrobacterium ATCC 31749.

3. The method according to claim 1 or 2, wherein the composition of the seed medium used for preparing the seed culture solution is: 1.0-2.0% of sucrose in percentage by mass; (NH)₄)₂HPO₄ 0.5～1.0％；KH₂PO₄ 0.15～0.2％；MgSO₄·7H₂O 0.1％；CaCO₃0.3 percent; 0.15-0.5% of corn steep liquor powder; adjusting the pH value to 7.2;

carrying out shaking culture at the temperature of 28-32 ℃ and at the speed of 150-240 r/min for 16-24 hours to obtain a seed culture solution.

4. The method according to claim 1 or 2, characterized in that the composition of the fermentation medium is: 5.0 percent of sucrose in percentage by mass; (NH)₄)₂HPO₄ 0.5～1.0％；KH₂PO₄ 0.15～0.2％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.1-0.5% of corn steep liquor powder; the pH was adjusted to 7.0.

5. The method according to claim 1 or 2, characterized in that the fermentation culture temperature is 28-32 ℃, the initial pH value is 7.0, the stirring speed is 120-200 r/min, the ventilation rate is 0.35-0.65 v.v.m, oxygen is introduced before the fermentation pH value is reduced to 5.4 inflection point, the oxygen introduction pressure is 0.3-0.5Mp, and the oxygen introduction time is 10-15 min.

Preferably, the fermentation is stopped when the cell concentration of the fermentation broth is >7.5 g/L.

6. The process as claimed in claim 1, characterized in that the total volume of the sugar solution fed in is 20 to 40% of the initial fermentation volume;

when the first flow is added, the adding amount of the sugar liquid is 7.5-15% of the volume of the initial fermentation liquid;

when the second time of flow, the adding amount of the sugar liquid is 7.5-15% of the volume of the initial fermentation liquid;

in the third flow, the sugar solution is added in an amount of 5-10% of the initial fermentation volume.

7. The method as claimed in claim 1 or 6, wherein 3-6mg/L UMP-promoting metabolic factor is further added at the time of first feeding.

8. The method according to claim 1 or 6, wherein the conversion temperature is 28-32 ℃, the stirring speed is 120-200 r/min, the ventilation rate is 0.3-0.5 v.v.m, and the sugar solution flow acceleration rate is 0.4-0.5 m³The pH value is maintained at 5.5-6.0, and the total conversion time is 58-65 h.

9. The method according to claim 1 or 6, wherein the sugar solution is a sucrose solution having a mass concentration of 20 to 50%.

10. Beta-1, 3-glucan obtainable by a process as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of microbial fermentation, in particular to a method for producing beta-1, 3-glucan by utilizing the non-growth coupling characteristic of bacteria.

Background

Beta-1, 3-glucan is a polysaccharide whose main chain is connected by beta-1, 3-glycosidic bonds, is a natural and harmless high molecular substance, and usually contains beta-1, 2/beta-1, 4/beta-1, 6-connected branched chains with different proportions and sizes due to different sources.

The beta-1, 3-glucan has the biological activities of enhancing the immune activity, resisting tumors, oxidation, bacteria, viruses, fungi, cholesterol and blood fat, and the like, and is a good biological effect regulator. Meanwhile, the skin care product has the effects of moisturizing, resisting inflammation, resisting aging, removing wrinkles, removing dandruff, removing jaundice, accelerating repair, increasing skin elasticity and the like, and is widely applied to a plurality of fields of medicines, foods, cosmetics, animal feed additives and the like.

At present, the beta-1, 3-glucan is mainly derived from yeast, edible fungi and plants (such as shiitake mushroom, oat and highland barley) and is limited by the complexity of the technology and the high cost, the beta-1, 3-glucan is mainly a crude product with low purity, the production process generates more byproducts, and the yield is limited by the cost of raw materials. The beta-1, 3-glucan is produced by microbial fermentation, and has the advantages of no limitation of seasons, stable and easily obtained raw material sources, no byproduct generation in the process and stable quality among batches.

Curdlan (Curdlan) is water-insoluble glucan synthesized by rhizobium bacteria and connected by beta-1, 3-D-glycosidic bonds, is obtained by batch fermentation in industrial production, has long production period and low yield, and needs to be consumed in a fermentation tank at the beginning of each period, and has large steam consumption.

The Chinese patent application CN110241150A beta-1, 3-glucan amplifying fermentation method comprises the following steps: firstly, preparing a strain activation culture medium according to KH₂PO₄ 0.3-1.0g/L；CaCl₂ 0.3-1.0g/L，MgSO₄ 0.6-1.2g/L，FeSO₄·7H₂Weighing substances with the mass concentration of 0.6-1.2g/L of O, 3.0-8.0g/L of sucrose and 12.0-18.0g/L of agar, dissolving in redistilled water to constant volume, adjusting the pH value to 6.5-7.0, and sterilizing at 115 ℃ for 30 minutes; secondly, strain activation, namely, streak-inoculating a strain to the strain activation culture medium obtained in the first step, standing at 25-30 ℃ and culturing for 2-3 days at constant temperature; step three, preparing a seed culture solutionWeighing the substances according to the mass concentration of 8.0-10.0g/L of peptone, 3.0-5.0g/L of yeast extract powder and 3.0-5.0g/L of sodium chloride, dissolving the substances in redistilled water to a constant volume, adjusting the pH value of a culture solution to 7.0-7.8, and sterilizing the culture solution for 20-30 minutes at the temperature of 121 ℃; fourthly, culturing seed liquid, scraping the activated strain from the strain activation culture medium, transferring the activated strain into 100mL of liquid seed culture liquid, and performing shake culture in a shaking table at the temperature of 28-32 ℃ and the speed of 300rpm for 48-72h until the OD600 value of the culture liquid is between 0.6 and 0.9, wherein the activated strain is used as the seed liquid for primary fermentation culture for later use; fifthly, preparing a primary fermentation culture solution, weighing the substances according to the mass concentrations of 8.0-10.0g/L of peptone, 3.0-5.0g/L of yeast extract powder and 3.0-5.0g/L of sodium chloride, dissolving the substances in redistilled water to a constant volume, adjusting the pH value of the culture solution to 7.0-7.8, and sterilizing the culture solution for 20-30 minutes at the temperature of 121 ℃; sixthly, culturing the amplified fermentation seed liquid, inoculating the seed liquid into the primary fermentation culture liquid according to the ratio of the seed liquid to the primary fermentation culture liquid (V/V) of 1: 300-800, fermenting for 1-2 days at 25-35 ℃ of a fermentation tank, adjusting the pH value to be 6.5-7.0, stirring at the speed of 150-200rpm and the ventilation volume of 0.4-0.5vvm until the OD600 value of the fermentation culture liquid is more than 0.9, and taking the seed liquid as the seed liquid for amplified fermentation culture for later use; seventhly, preparing an amplified fermentation culture solution, weighing according to the mass concentration of 120g/L of sucrose, dissolving by redistilled water to a constant volume, adjusting the pH value of the culture solution to 7.0-7.8, and introducing steam to sterilize for 30 minutes at 115 ℃; eighth step, amplification fermentation culture, inoculating the primary fermentation broth into the amplification fermentation culture solution according to the proportion of the primary fermentation culture solution to the amplification fermentation culture solution (V/V) being 1: 300-; timing sampling detection, when the nitrogen source is exhausted, adjusting the pH value to 5.5, wherein the error is not more than +/-0.1, the stirring speed is 400-600rpm, and the ventilation volume is 0.7-0.8vvm, and finally obtaining the crude product of the beta-1, 3-glucan. The highest yield of the crude product of the beta-1, 3-glucan obtained by the method is 49.7 mg/mL. The method has complicated steps and the yield of the obtained beta-1, 3-glucan is low.

Disclosure of Invention

The invention mainly aims to provide a method for producing beta-1, 3-glucan by utilizing the non-growth coupling characteristic of bacteria, and the method can obviously improve the yield of the beta-1, 3-glucan, shorten the production period, reduce the production cost and overcome the defects of the existing fermentation process by adopting a high-density fermentation culture and fed-batch glucose-supplementing whole cell transformation mode.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for producing beta-1, 3-glucan by utilizing the non-growth coupling characteristic of bacteria, which comprises the following steps:

s1, activating a strain producing beta-1, 3-glucan to prepare a seed culture solution;

s2, inoculating the seed culture solution into a fermentation culture medium for fermentation culture;

s3, after fermentation is finished, transferring 60-80% of fermentation liquor into a conversion tank; adding a fermentation culture medium into the rest 20-40% of the fermentation liquor to the initial fermentation volume, continuing to perform secondary fermentation, and transferring 60-80% of the fermentation liquor into a conversion tank after the fermentation is finished; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is 1h after the fermentation liquor is transferred;

the second feeding time is 30-35 hours after the fermentation liquor is transferred;

the third feeding time is 40-45h after the fermentation liquor is converted.

Further, the β -1, 3-glucan producing strain is agrobacterium ATCC 31749.

Further, the composition of the seed medium used for preparing the seed culture solution is: 1.0-2.0% of sucrose in percentage by mass; (NH)₄)₂HPO₄ 0.5～1.0％；KH₂PO₄ 0.15～0.2％；MgSO₄·7H₂O 0.1％；CaCO₃0.3 percent; 0.15-0.5% of corn steep liquor powder; adjusting the pH value to 7.2;

carrying out shaking culture at the temperature of 28-32 ℃ and at the speed of 150-240 r/min for 16-24 hours to obtain a seed culture solution.

Further, the composition of the fermentation medium was: 5.0 percent of sucrose in percentage by mass; (NH)₄)₂HPO₄ 0.5～1.0％；KH₂PO₄ 0.15～0.2％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.1-0.5% of corn steep liquor powder; the pH was adjusted to 7.0.

Further, the fermentation culture temperature is 28-32 ℃, the initial pH value is 7.0, the stirring speed is 120-200 r/min, the ventilation rate is 0.35-0.65 v.v.m, oxygen is introduced before the fermentation pH value is reduced to 5.4 inflection points, the oxygen pressure is 0.3-0.5Mp, and the oxygen introduction time is 10-15 min.

Further, when the cell concentration of the fermentation solution is more than 7.5g/L, the fermentation is stopped.

Furthermore, the total volume of the sugar liquid added in a flow manner is 20-40% of the initial fermentation volume;

when the first flow is added, the adding amount of the sugar liquid is 7.5-15% of the volume of the initial fermentation liquid;

when the second time of flow, the adding amount of the sugar liquid is 7.5-15% of the volume of the initial fermentation liquid;

in the third flow, the sugar solution is added in an amount of 5-10% of the initial fermentation volume.

Further, 3-6mg/L UMP metabolism promoting factors are added during the first feeding.

Further, the conversion temperature is 28-32 ℃, the stirring speed is 120-200 r/min, the ventilation rate is 0.3-0.5 v.v.m, and the sugar solution flow acceleration rate is 0.4-0.5 m³The pH value is maintained at 5.5-6.0, and the total conversion time is 58-65 h.

Further, the sugar solution is a sucrose solution with a mass concentration of 20-50%.

The invention also provides the beta-1, 3-glucan prepared by the method.

Compared with the prior art, the invention has the following beneficial effects:

the method adopts a non-coupling fermentation method, and organically combines the high-density culture of microorganisms and the whole-cell catalysis of fed-batch materials, thereby improving the yield of the beta-1, 3-glucan, shortening the production period and reducing the production cost of the beta-1, 3-glucan. Compared with the existing intermittent fermentation production mode, the method utilizes the non-growth coupled fermentation characteristic of curdlan produced by the strains, utilizes the remained mature fermentation culture solution in the high-density culture stage, and then inserts the fresh culture solution, and because the basic quantity of the cells of the strains is large, the cell proliferation and biomass accumulation speed is obviously accelerated, and the cells directly enter the logarithmic growth phase after passing through the lag phase, so that the production period can be obviously reduced; in the whole-cell conversion stage, high conversion of beta-1, 3-glucan can be realized only by controlling the concentration and feeding speed of fed-batch sugar solution, the sugar concentration is increased from 5% of the original batch fermentation to 12-14%, the yield of the beta-1, 3-glucan is more than 8%, and a brand-new fermentation production mode is realized.

The equipment, high-density culture and fed-batch material supplement processes adopted by the invention are simple, and the popularization in industrial production is facilitated; can obviously improve the yield of the beta-1, 3-glucan, shorten the production period, is beneficial to reducing the production cost of the beta-1, 3-glucan, and can meet the requirement of wider application in the fields of food, medicine and the like, thereby improving the commercial value of the beta-1, 3-glucan.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

The method for measuring the bacterial quantity comprises the steps of adding 400ml of 1mol/L sodium hydroxide solution into 100ml of fermentation liquor, stirring at a high speed for 15min, dissolving, centrifuging for 10min at 10000r/min by using a centrifuge, discarding supernatant, washing and centrifuging precipitates twice by using 1mol/L hydrochloric acid solution, washing and centrifuging once by using distilled water, collecting precipitates, drying at a constant temperature of 105 ℃ to constant weight, weighing, and dividing the weight by the volume of the fermentation liquor to obtain the bacterial quantity.

The method for measuring the content of the beta-1, 3-glucan comprises the steps of adding 400ml of 1mol/L sodium hydroxide solution into 100ml of conversion solution, stirring at a high speed for 15min, dissolving, centrifuging for 10min at 10000r/min by using a centrifugal machine, collecting supernatant, adjusting the pH value of the supernatant to 7.0 by using 4mol/L hydrochloric acid to form neutralized gel, centrifuging for 10min at 5000rpm to obtain a solid matter, washing twice by using 95% (v/v) alcohol, drying at low temperature to obtain crude polysaccharide, weighing, and dividing the weight by the product of the conversion solution to obtain the content of the beta-1, 3-glucan.

The beta-1, 3-glucan producing strain used in this example was Agrobacterium ATCC 31749 strain, but the beta-1, 3-glucan producing strain described herein includes, but is not limited to Agrobacterium ATCC 31749 strain.

Example 1

A method for producing beta-1, 3-glucan by utilizing the non-growth coupled property of bacteria, comprising the steps of:

s1, inoculating a shovel of agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 30 ℃ and 240r/min for 20 hours to obtain an activated strain seed culture solution for producing beta-1, 3-glucan.

Wherein, the seed culture medium comprises 2% of sucrose; (NH)₄)₂HPO₄ 0.5％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.15 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

S2, inoculating the second-level seed culture solution into a 20-ton tank with a constant volume of 16m in an inoculation amount of 5%³Culturing in a fermentation tank of a fermentation medium at the fermentation temperature of 30 ℃, the initial pH value of 7.0, the ventilation quantity of 0.6v.v.m., the stirring rotation speed of 150r/min for 10 hours, introducing oxygen before the fermentation pH value is reduced to 5.4 inflection points, introducing oxygen at the pressure of 0.3Mp, and introducing oxygen for 10 min; when the pH value reaches 5.4, stopping fermentation; the culture bacterial amount reaches 7.58 g/L.

Wherein, the composition of the fermentation liquid culture medium is 5.0 percent of sucrose; (NH)₄)₂HPO₄ 0.2％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.2 percent of corn steep liquor powder; adjusting the pH value to 7.0; sterilizing at 121 deg.C for 20 min.

S3, after fermentation is finished, transferring 70% of high-concentration thallus fermentation liquor in the fermentation tank to 20m³In the conversion tank, adding a fermentation medium into the remaining 30% of the fermentation liquor to the initial fermentation volume, continuing to perform secondary fermentation, and after the fermentation is finished, transferring 70% of the fermentation liquor into the conversion tank; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is within 1h after the fermentation broth is transferred, and the adding amount of sugar liquid is 12% of the volume of the initial fermentation broth;

the second feeding time is 30 hours after the fermentation broth is transferred, and the adding amount of sugar liquid is 12 percent of the volume of the initial fermentation broth;

the third feeding time is 42h after the fermentation liquor is converted, and the adding amount of sugar liquor is 6% of the initial fermentation volume.

The conversion temperature is 30 ℃, the ventilation rate is 0.35v.v.m., the stirring rotating speed is 120r/min, and the sugar liquid flow acceleration is 0.4m³The pH value is maintained at 5.8, the conversion is carried out for 62 hours, and the yield of the beta-1, 3-glucan is 85 g/L; the carbon source conversion rate is 70.8 percent; the conversion strength was 32.9 g/L/d.

The sugar solution used is a sucrose solution with the mass concentration of 30%.

Example 2

A method for producing beta-1, 3-glucan by utilizing the non-growth coupled property of bacteria, comprising the steps of:

s1, inoculating a shovel of agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 30 ℃ and 240r/min for 20 hours to obtain an activated strain seed culture solution for producing beta-1, 3-glucan.

Wherein, the seed culture medium comprises 2% of sucrose; (NH)₄)₂HPO₄ 0.5％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃ 015%; 0.15 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

S2, inoculating the second-level seed culture solution into a 20-ton tank with a constant volume of 16m in an inoculation amount of 5%³Culturing in a fermentation tank of fermentation medium at 30 deg.C, initial pH of 7.0, ventilation rate of 0.45v.v.m., stirring speed of 180r/min, introducing oxygen before fermentation pH decreases to 5.4 inflection point, introducing oxygen pressure of 0.3Mp, and introducing oxygen for 10 min; when the pH reached 5.4, the fermentation was stopped. The culture bacterial amount reaches 7.82 g/L.

Wherein, the composition of the fermentation liquid culture medium is 5.0 percent of sucrose; (NH)₄)₂HPO₄ 0.2％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.2 percent of corn steep liquor powder; adjusting the pH value to 7.0; sterilizing at 121 deg.C for 20 min.

S3, after fermentation is finished, transferring 70% of high-concentration thallus fermentation liquor in the fermentation tank to 20m³In the conversion tank, adding a fermentation medium into the remaining 30% of the fermentation liquor to the initial fermentation volume, continuing to perform secondary fermentation, and after the fermentation is finished, transferring 70% of the fermentation liquor into the conversion tank; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is within 1h after the fermentation broth is transferred, the adding amount of sugar liquid is 12% of the volume of the initial fermentation broth, and 5mg/L UMP metabolism promoting factors are added after sugar is supplemented;

the second feeding time is 30 hours after the fermentation broth is transferred, and the adding amount of sugar liquid is 12 percent of the volume of the initial fermentation broth;

the third feeding time is 42h after the fermentation liquor is converted, and the adding amount of sugar liquor is 6% of the initial fermentation volume.

The conversion temperature is 30 ℃, the ventilation rate is 0.35v.v.m., the stirring rotating speed is 120r/min, and the sugar liquid flow acceleration is 0.4m³The yield of the beta-1, 3-glucan is 87g/L after the conversion is carried out for 62 hours by maintaining the pH value at 5.8; carbon source conversion rate 72.5%; the conversion strength was 33.7 g/L/d.

The sugar solution used is a sucrose solution with the mass concentration of 30%.

Example 3

A method for producing beta-1, 3-glucan by utilizing the non-growth coupled property of bacteria, comprising the steps of:

s1, inoculating a shovel of agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 30 ℃ and 240r/min for 20 hours to obtain an activated strain seed culture solution for producing beta-1, 3-glucan.

Wherein, the seed culture medium comprises 2% of sucrose; (NH)₄)₂HPO₄ 0.5％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.15 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

S2, inoculating the second-level seed culture solution into a 20-ton tank with a constant volume of 16m in an inoculation amount of 5%³Culturing in a fermentation tank of a fermentation medium at 30 ℃, with an initial pH of 7.0, a ventilation rate of 0.35v.v.m., a stirring rotation speed of 180r/min for 10 hours, introducing oxygen before the fermentation pH is reduced to a 5.4 inflection point, introducing oxygen at a pressure of 0.3Mp, and introducing oxygen for 15 min; when the pH value reaches 5.4, stopping fermentation; the culture bacterial amount reaches 7.63 g/L.

Wherein, the composition of the fermentation liquid culture medium is 5.0 percent of sucrose; (NH)₄)₂HPO₄ 0.2％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.2 percent of corn steep liquor powder; adjusting the pH value to 7.0; sterilizing at 121 deg.C for 20 min.

S3, after fermentation is finished, transferring 70% of high-concentration thallus fermentation liquor in the fermentation tank to 20m³In the conversion tank, adding a fermentation medium into the remaining 30% of the fermentation liquor to the initial fermentation volume, continuing to perform secondary fermentation, and after the fermentation is finished, transferring 70% of the fermentation liquor into the conversion tank; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is within 1h after the fermentation broth is transferred, the adding amount of sugar liquid is 12% of the volume of the initial fermentation broth, and 6mg/L UMP metabolism promoting factors are added after sugar is supplemented;

the second feeding time is 30 hours after the fermentation broth is transferred, and the adding amount of sugar liquid is 12 percent of the volume of the initial fermentation broth;

the third feeding time is 42h after the fermentation liquor is converted, and the adding amount of sugar liquor is 6% of the initial fermentation volume.

The conversion temperature is 30 ℃, the ventilation rate is 0.35v.v.m., the stirring rotating speed is 120r/min, and the sugar liquid flow acceleration is 0.4m³The pH value is maintained at 5.8, the conversion is carried out for 65 hours, and the yield of the beta-1, 3-glucan is 86 g/L; carbon source conversion rate 71.7%; the conversion strength was 31.8 g/L/d. The sugar solution used is a sucrose solution with the mass concentration of 30%.

Example 4

A method for producing beta-1, 3-glucan by utilizing the non-growth coupled property of bacteria, comprising the steps of:

s1, inoculating a shovel of agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 28 ℃ and 150r/min for 24 hours to obtain an activated strain seed culture solution for producing beta-1, 3-glucan.

Wherein, the seed culture medium comprises 1% of sucrose; (NH)₄)₂HPO₄ 1％；KH₂PO₄ 0.5％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.5 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

S2, inoculating the second-level seed culture solution into a 20-ton tank with a constant volume of 16m in an inoculation amount of 5%³Culturing in a fermentation tank of a fermentation medium at 30 ℃, with an initial pH of 7.0, a ventilation rate of 0.65v.v.m., a stirring speed of 150r/min for 10 hours, introducing oxygen before the fermentation pH is reduced to a 5.4 inflection point, introducing oxygen at a pressure of 0.5Mp, and introducing oxygen for 15 min; when the pH reached 5.4, the fermentation was stopped. The culture bacterial amount reaches 7.71 g/L.

Wherein, the composition of the fermentation liquid culture medium is 5.0 percent of sucrose; (NH)₄)₂HPO₄ 0.2％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.2 percent of corn steep liquor powder; adjusting the pH value to 7.0; sterilizing at 121 deg.C for 20 min.

S3, after fermentation is finished, 80% of high-concentration thallus fermentation liquor in the fermentation tank is transferred to20m³In the conversion tank, adding a fermentation medium into the remaining 20% of the fermentation liquor to the initial fermentation volume, continuing to perform secondary fermentation, and after the fermentation is finished, transferring 80% of the fermentation liquor into the conversion tank; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is within 1h after the fermentation broth is transferred, and the adding amount of sugar liquid is 7.5 percent of the volume of the initial fermentation broth;

the second feeding time is 35 hours after the fermentation broth is transferred, and the adding amount of sugar liquid is 7.5 percent of the volume of the initial fermentation broth;

the third feeding time is 45 hours after the fermentation liquor is converted, and the adding amount of sugar liquor is 5 percent of the initial fermentation volume.

The conversion temperature is 30 ℃, the ventilation rate is 0.5v.v.m., the stirring rotating speed is 120r/min, and the sugar liquid flow acceleration is 0.5m³The pH value is maintained at 5.5, the conversion is carried out for 58 hours, and the yield of the beta-1, 3-glucan is 82 g/L; carbon source conversion rate is 68.3%; the conversion strength was 33.9 g/L/d. The sugar solution used is a sucrose solution with the mass concentration of 30%.

Example 5

A method for producing beta-1, 3-glucan by utilizing the non-growth coupled property of bacteria, comprising the steps of:

s1, inoculating a shovel of agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 30 ℃ and 240r/min for 20 hours to obtain an activated strain seed culture solution for producing beta-1, 3-glucan.

Wherein, the seed culture medium comprises 2% of sucrose; (NH)₄)₂HPO₄ 0.5％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.15 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

S2, inoculating the secondary seed culture solution into a 50L fermentation tank with constant volume of 30L fermentation medium for culture at the fermentation temperature of 30 ℃, the initial pH value of 7.0, the ventilation quantity of 0.45v.v.m., the stirring rotation speed of 180r/min, culturing for 10 hours, introducing oxygen before the fermentation pH value is reduced to the inflection point of 5.4, introducing oxygen at the pressure of 0.3Mp, and introducing oxygen for 10 min; when the pH reached 5.4, the fermentation was stopped. The culture bacterial amount reaches 7.82 g/L.

Wherein, the composition of the fermentation liquid culture medium is 5.0 percent of sucrose; (NH)₄)₂HPO₄ 0.2％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.2 percent of corn steep liquor powder; adjusting the pH value to 7.0; sterilizing at 121 deg.C for 20 min.

S3, after fermentation is finished, transferring 70% of high-concentration thallus fermentation liquor in the fermentation tank to a 50L conversion tank, adding a fermentation culture medium to the remaining 30% of the fermentation liquor to reach an initial fermentation volume, continuing to perform secondary fermentation, and after the fermentation is finished, transferring 70% of the fermentation liquor into the conversion tank; circulating for 5-6 times;

s4, adding sugar liquor into the conversion tank in a fractional flow manner to perform whole-cell conversion:

the first feeding time is within 1h after the fermentation broth is transferred, the adding amount of sugar liquid is 12% of the volume of the initial fermentation broth, and 5mg/L UMP metabolism promoting factors are added after sugar is supplemented;

the second feeding time is 30 hours after the fermentation broth is transferred, and the adding amount of sugar liquid is 12 percent of the volume of the initial fermentation broth;

the third feeding time is 42h after the fermentation liquor is converted, and the adding amount of sugar liquor is 6% of the initial fermentation volume.

The conversion temperature is 30 ℃, the ventilation rate is 0.35v.v.m., the stirring rotating speed is 120r/min, and the sugar liquid flow acceleration is 0.4m³The pH value is maintained at 5.8, the conversion is carried out for 62 hours, and the yield of the beta-1, 3-glucan is 88 g/L; carbon source conversion rate 73.3%; the conversion strength was 34.1 g/L/d. The sugar solution used is a sucrose solution with the mass concentration of 30%.

Comparative example 1

Inoculating a shovel of the agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 30 ℃ and 240r/min for 20 hours to obtain an activated strain seed culture solution for producing the beta-1, 3-glucan.

Wherein, the seed culture medium comprises 2% of sucrose; (NH)₄)₂HPO₄ 0.5％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.15 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

Inoculating the mixture into a fermentation medium containing 30L in a 50L fermentation tank at the fermentation temperature of 30 ℃, the initial pH value of 7.0, the ventilation rate of 0.45v.v.m., the stirring speed of 180r/min, introducing oxygen before the fermentation pH value is reduced to 5.4 inflection points, introducing oxygen at the pressure of 0.3Mp and introducing oxygen for 10 min; the fermentation time was 96 hours. Wherein the fermentation medium comprises sucrose 5.0%; (NH)₄)₂HPO₄0.2％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.3 percent; 0.2 percent of corn steep liquor powder; pH 7.0; sterilizing at 121 deg.C for 20 min. The bacterial count reaches 3.15g/L, and the yield of beta-1, 3-glucan is 32 g/L; carbon source conversion rate 64%; the fermentation intensity is 8.0 g/L/d.

Comparative example 2

Inoculating a shovel of the agrobacterium tumefaciens ATCC 31749 slant culture medium into a seed culture medium by using an inoculating shovel, and performing shaking culture at 30 ℃ and 240r/min for 20 hours to obtain an activated strain seed culture solution for producing the beta-1, 3-glucan.

Wherein, the seed culture medium comprises 2% of sucrose; (NH)₄)₂HPO₄ 0.5％；KH₂PO₄ 0.15％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.15 percent of corn steep liquor powder; adjusting the pH value to 7.2; sterilizing at 121 deg.C for 20 min.

Inoculating the mixture into a fermentation medium containing 30L in a 50L fermentation tank at the fermentation temperature of 30 ℃, the initial pH value of 7.0, the ventilation rate of 0.45v.v.m., the stirring speed of 180r/min, introducing oxygen before the fermentation pH value is reduced to 5.4 inflection points, introducing oxygen at the pressure of 0.3Mp and introducing oxygen for 10 min; the fermentation time was 96 hours. Wherein the composition of the fermentation liquid culture medium is 8.0 percent of sucrose; (NH4)2HPO 40.15%; KH (Perkin Elmer)₂PO₄ 0.2％；MgSO₄·7H₂O 0.1％；CaCO₃0.15 percent; 0.2 percent of corn steep liquor powder; adjusting the pH value to 7.0; sterilizing at 121 deg.C for 20 min. The bacterial amount reaches 3.20g/L, the yield of beta-1, 3-glucan is 48.9 g/L; carbon source conversion rate is 61.12%; the fermentation intensity is 12.23 g/L/d.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.