阅读说明：本技术 一种高效生产味精的方法 (Method for efficiently producing monosodium glutamate ) 是由 赵兰坤 徐庆阳 孙钦波 刘景阳 李树标 王峰 赵凤良 王小平 吴国强 于 2020-11-04 设计创作，主要内容包括：本发明属于发酵技术领域,公开了一种高效生产味精的方法,其包括如下步骤：1)菌株活化；2)制备种子液；3)发酵；4)陶瓷膜过滤；5)超滤膜过滤；6)味精制备；7)减压浓缩；8)脱色；9)反渗透过浓缩；9)减压浓缩；10)冷冻结晶；11)离心,干燥。本发明提供的一种高效提取味精的方法,能够提高味精的生产能力和提取效率,降低污染,从而降低生产成本,提高经济效益。(The invention belongs to the technical field of fermentation, and discloses a method for efficiently producing monosodium glutamate, which comprises the following steps: 1) activating a strain; 2) preparing a seed solution; 3) fermenting; 4) filtering by a ceramic membrane; 5) filtering with an ultrafiltration membrane; 6) preparing monosodium glutamate; 7) concentrating under reduced pressure; 8) decoloring; 9) reverse osmosis concentration; 9) concentrating under reduced pressure; 10) freezing and crystallizing; 11) centrifuging and drying. The method for efficiently extracting the monosodium glutamate provided by the invention can improve the production capacity and extraction efficiency of the monosodium glutamate and reduce pollution, thereby reducing the production cost and improving the economic benefit.)

1. The method for efficiently producing monosodium glutamate is characterized by comprising the following steps: 1) activating a strain; 2) preparing a seed solution; 3) fermenting; 4) filtering by a ceramic membrane; 5) filtering with an ultrafiltration membrane; 6) preparing monosodium glutamate; 7) concentrating under reduced pressure; 8) decoloring; 9) reverse osmosis concentration; 9) concentrating under reduced pressure; 10) freezing and crystallizing; 11) centrifuging and drying.

2. The method for efficiently producing monosodium glutamate according to claim 1, wherein: the method comprises the following steps:

1) strain activation: taking out Corynebacterium glutamicum GDK-9 from a refrigerator at-80 ℃, inoculating the Corynebacterium glutamicum GDK-9 on a slant culture medium, and carrying out passage twice to obtain an activated strain;

2) preparing a seed solution: eluting the strain on the inclined plane by using sterile water, inoculating the strain into a fermentation tank containing a seed culture medium, controlling the temperature at 34 ℃, controlling the dissolved oxygen at 30-50% and controlling the pH at about 7.0 by using ammonia water;

3) fermentation: when OD of seed liquid₆₀₀When the inoculation amount reaches 20%, inoculating the seed liquid into a fermentation tank containing a fermentation culture medium according to the inoculation amount of 20%; controlling the initial temperature at 34 ℃, raising the temperature by 0.5 ℃ every 4 h, and stopping raising the temperature to 37 ℃; controlling the dissolved oxygen passing speed and ventilation to be 30-50%; the pH is controlled to be about 7.0 by feeding alkaline mixed liquor;

4) ceramic membrane filtration: heating the fermentation liquor to 80-90 ℃, and filtering by using a ceramic membrane to remove thalli and macromolecular proteins in the fermentation liquor to obtain filtered fermentation liquor;

5) and (3) ultrafiltration membrane filtration: maintaining the temperature of the filtered fermentation liquor at 80-90 ℃, and filtering with an ultrafiltration membrane to obtain clarified fermentation liquor;

6) monosodium glutamate preparation: respectively flowing the clarified fermentation liquor and 1 mol/L NaOH solution into a stirring tank in proportion, and quickly pumping into a reduced pressure concentration tank after uniformly mixing in the stirring tank;

7) and (3) concentrating under reduced pressure: then pumping the mixture into a decompression concentration tank, vacuumizing the decompression concentration tank, keeping the temperature at 70-80 ℃, and concentrating the mixture to be half of the original volume;

8) and (3) decoloring: adding active carbon into the concentrated fermentation liquor, mixing uniformly, and performing suction filtration;

9) reverse osmosis concentration: concentrating the decolorized fermentation liquor through a reverse osmosis filter, wherein the membrane inlet pressure of the reverse osmosis filter is 1.5-3 Mpa, and the temperature of the fermentation liquor is 80-90 ℃;

9) and (3) concentrating under reduced pressure: after reverse osmosis concentration, further concentrating the fermentation liquor by reduced pressure concentration to obtain saturated sodium glutamate solution;

10) freezing and crystallizing: crystallizing the obtained saturated solution of sodium glutamate in a low-temperature freezing crystallization tank, and maintaining the temperature at 5-10 ℃;

11) centrifuging and drying.

3. The method for efficiently producing monosodium glutamate according to claim 2, wherein:

the slant culture medium: peptone 10 g/L; 10 g/L of beef extract; 5 g/L of yeast powder; 25 mL/L of corn steep liquor; KH (Perkin Elmer)₂PO₄ 1 g/L；MgSO₄0.5 g/L; NaCl 2.5 g/L; 25 g/L of agar powder.

4. The method for efficiently producing monosodium glutamate according to claim 2, wherein:

the seed culture medium is as follows: 35 g/L of glucose; corn steep liquor dry powder15 g/L; 20 mL/L of soybean meal hydrolysate; k₂HPO₄ 3.5 g/L；MgSO₄ 1 g/L；V_B1 0.5 mg/L；V_B3 0.5 mg/L；V_B5 0.5 mg/L；VB₁₂0.5 mg/L。

5. The method for efficiently producing monosodium glutamate according to claim 2, wherein: the alkaline mixed solution is prepared from 1 mol/L NaOH and 25% ammonia water according to a ratio of 4: 6-6: 4.

6. The method for efficiently producing monosodium glutamate according to claim 2, wherein: the molecular weight cut-off of the ceramic membrane is 30000 Da.

7. The method for efficiently producing monosodium glutamate according to claim 2, wherein: the molecular weight cut-off of the ultrafiltration membrane is 2000 Da.

8. The method for efficiently producing monosodium glutamate according to claim 2, wherein: in the monosodium glutamate preparation, the feeding proportion of the clarified fermentation liquor to 1 mol/L NaOH solution is 1: 0.5-1: 1.5.

9. the method for efficiently producing monosodium glutamate according to claim 2, wherein: the equipment used for the reduced pressure concentration is a three-effect concentrator.

Technical Field

The invention belongs to the technical field of fermentation, and relates to a method for efficiently producing monosodium glutamate.

Background

Monosodium glutamate, known as monosodium glutamate and chemical name alpha-amino monosodium glutarate, is a sodium salt of glutamic acid, is a common seasoning in daily life, and can obviously increase the delicate flavor of food. In addition, monosodium glutamate can be hydrolyzed into L-glutamic acid by gastric acid after being taken into human body, and has positive effects in preventing and treating hepatic coma, protecting liver, and promoting normal physiological activity of central nervous system. Through the development of many years, the annual output of the monosodium glutamate industry in China reaches more than 170 million tons, more than 50 countries are exported, the sales income is nearly 180 million yuan, and the market prospect is huge. However, the following problems still exist in the production of monosodium glutamate:

1. the fermentation efficiency is low. L-glutamic acid is a precursor substance for producing monosodium glutamate, and although the yield of the L-glutamic acid is continuously improved along with the deep development of technologies such as genetic engineering and the like in recent years, the problems of high production cost, low enterprise income and the like still exist;

2. the pollution is serious. At present, most of monosodium glutamate is extracted by adopting an isoelectric-ion exchange method, and during the production process, concentrated sulfuric acid is added to adjust isoelectric points so as to crystallize glutamic acid, so that a large amount of ammonium sulfate waste liquid is generated in the process, great difficulty is brought to waste liquid treatment, and the production cost is increased.

3. The by-products are numerous. The preparation of the monosodium glutamate is mainly to add 10 percent sodium carbonate aqueous solution by mass fraction into glutamic acid crystals for dissolving and neutralizing, thereby obtaining the monosodium glutamate. This method has a long reaction time and is liable to cause side reactions, which in turn leads to the formation of by-products.

Disclosure of Invention

The invention aims to overcome the problems, and provides a method for efficiently producing monosodium glutamate, which can improve the production capacity and extraction efficiency of monosodium glutamate and reduce pollution, thereby reducing the production cost and improving the economic benefit.

The main solution of the invention is realized as follows:

a method for efficiently producing monosodium glutamate comprises the following steps:

1) strain activation: taking out Corynebacterium glutamicum GDK-9 from a refrigerator at-80 ℃, inoculating the Corynebacterium glutamicum GDK-9 on a slant culture medium, and carrying out passage twice to obtain an activated strain;

2) preparing a seed solution: eluting the strains on the inclined plane by using sterile water, completely inoculating the strains into a fermentation tank containing a seed culture medium, controlling the temperature at 34 ℃, controlling the dissolved oxygen at 30-50% and controlling the pH at about 7.0 by using ammonia water;

3) fermentation: when OD of seed liquid₆₀₀When 20% was reached, the seed solution was inoculated into a fermenter containing a fermentation medium at an inoculum size of 20%. Controlling the initial temperature at 34 ℃, raising the temperature by 0.5 ℃ every 4 h, and stopping raising the temperature to 37 ℃; controlling the dissolved oxygen passing speed and ventilation to be 30-50%; the pH is controlled to be about 7.0 by feeding alkaline mixed liquor;

4) ceramic membrane filtration: heating the fermentation liquor to 80-90 ℃, and filtering by using a ceramic membrane to remove thalli and macromolecular proteins in the fermentation liquor to obtain filtered fermentation liquor;

5) and (3) ultrafiltration membrane filtration: maintaining the temperature of the filtered fermentation liquor at 80-90 ℃, and filtering with an ultrafiltration membrane to obtain clear fermentation liquor;

6) monosodium glutamate preparation: respectively flowing the obtained clarified fermentation liquor and 1 mol/L NaOH solution into a stirring tank in proportion, and quickly pumping into a reduced pressure concentration tank after uniformly mixing in the stirring tank;

7) and (3) concentrating under reduced pressure: pumping the mixed fermentation liquor into a reduced pressure concentration tank, vacuumizing, keeping the temperature at 70-80 ℃, and concentrating to obtain a volume which is one half of the original volume;

8) and (3) decoloring: adding active carbon into the concentrated fermentation liquor, mixing uniformly, and performing suction filtration;

9) reverse osmosis concentration: concentrating the decolorized fermentation liquor through a reverse osmosis filter, wherein the membrane inlet pressure of the reverse osmosis filter is 1.5-3 Mpa, and the temperature of the fermentation liquor is 80-90 ℃;

9) and (3) concentrating under reduced pressure: after reverse osmosis concentration, further concentrating the fermentation liquor by reduced pressure concentration to obtain saturated sodium glutamate solution;

10) freezing and crystallizing: crystallizing the obtained saturated solution of sodium glutamate in a low-temperature freezing crystallization tank, and maintaining the temperature at 5-10 ℃;

11) centrifuging and drying.

Preferably, the slant culture medium in the method for efficiently producing monosodium glutamate comprises: peptone 10 g/L; 10 g/L of beef extract; 5 g/L of yeast powder; 25 mL/L of corn steep liquor; KH (Perkin Elmer)₂PO₄ 1 g/L；MgSO₄0.5 g/L; NaCl 2.5 g/L; 25 g/L of agar powder.

Preferably, the seed culture medium in the method for efficiently extracting monosodium glutamate is: 35 g/L of glucose; 15 g/L of corn steep liquor dry powder; 20 mL/L of soybean meal hydrolysate; k₂HPO₄ 3.5 g/L；MgSO₄ 1 g/L；V_B1 0.5 mg/L；V_B3 0.5 mg/L；V_B5 0.5 mg/L；VB₁₂0.5 mg/L；

Preferably, the alkaline mixed solution in the method for efficiently producing monosodium glutamate is prepared from 1 mol/L NaOH and 25% ammonia water according to a ratio of 4: 6-6: 4.

Preferably, in the method for efficiently producing monosodium glutamate, the membrane filtration system with a molecular weight cutoff of 30000 is used for filtration, and is used for removing thalli and macromolecular proteins in the fermentation broth.

Preferably, the ultrafiltration is performed by using a membrane filtration system with a molecular weight cut-off of 2000, so as to further remove small-molecule proteins.

Preferably, in the method for efficiently producing monosodium glutamate, the feeding proportion of the clarified fermentation liquor and the 1 mol/L NaOH solution in the monosodium glutamate preparation is 1: 0.5-1: 1.5

Preferably, in the method for efficiently producing monosodium glutamate, the equipment used for the reduced pressure concentration is a three-effect concentrator.

The advantages achieved by the present invention mainly include, but are not limited to, the following:

1. according to the invention, ammonia water is replaced by alkaline mixed liquor in the fermentation process, so that the inhibition of the activity and acid production capability of thalli by ammonium salt in the fermentation process can be avoided, and the yield of L-glutamic acid is improved;

2. the invention replaces the isoelectric-ion exchange technology with the membrane filtration technology, greatly reduces the consumption of concentrated sulfuric acid, reduces the treatment difficulty of waste liquid and reduces the production cost;

3. in the invention, NaOH and fermentation liquor are mixed in proportion and then are quickly pumped into a concentration tank for subsequent operation in the preparation of monosodium glutamate, the reaction in the whole process is quick, and the generation of byproducts caused by a long-time reaction process is avoided.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the present application will be clearly and completely described below with reference to specific embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

A method for efficiently producing monosodium glutamate comprises the following steps:

1) strain activation: taking out Corynebacterium glutamicum GDK-9 from a refrigerator at-80 ℃, inoculating the Corynebacterium glutamicum GDK-9 on a slant culture medium, and carrying out passage twice to obtain an activated strain;

2) preparing a seed solution: eluting the strains on the inclined plane by using sterile water, completely inoculating the strains into a fermentation tank containing a seed culture medium, controlling the temperature at 34 ℃, controlling the dissolved oxygen at 30-50% and controlling the pH at about 7.0 by using ammonia water;

3) fermentation: when OD of seed liquid₆₀₀When 20% was reached, the seed solution was inoculated into a fermenter containing a fermentation medium at an inoculum size of 20%. Controlling the initial temperature at 34 ℃, raising the temperature by 0.5 ℃ every 4 h, and stopping raising the temperature to 37 ℃; controlling the dissolved oxygen passing speed and ventilation to be 30-50%; the pH is controlled to be about 7.0 by feeding alkaline mixed liquor, and the alkaline mixed liquor is prepared by 1 mol/L NaOH and 25% ammonia water according to the proportion of 6: 4;

4) ceramic membrane filtration: heating the fermentation liquor to 80-90 ℃, and filtering by using a ceramic membrane to remove thalli and macromolecular proteins in the fermentation liquor to obtain filtered fermentation liquor;

5) and (3) ultrafiltration membrane filtration: maintaining the temperature of the filtered fermentation liquor at 80-90 ℃, and filtering with an ultrafiltration membrane to obtain clear fermentation liquor;

6) monosodium glutamate preparation: mixing the obtained clear fermentation liquor and 1 mol/L NaOH solution according to the weight ratio of 1:1 respectively flowing into a stirring tank, uniformly mixing in the stirring tank, and quickly pumping into a reduced-pressure concentration tank;

7) and (3) concentrating under reduced pressure: pumping the mixed fermentation liquor into a reduced pressure concentration tank, vacuumizing, keeping the temperature at 70-80 ℃, and concentrating to obtain a volume which is one half of the original volume;

8) and (3) decoloring: adding active carbon into the concentrated fermentation liquor, mixing uniformly, and performing suction filtration;

9) reverse osmosis concentration: concentrating the decolorized fermentation liquor through a reverse osmosis filter, wherein the membrane inlet pressure of the reverse osmosis filter is 1.5-3 Mpa, and the temperature of the fermentation liquor is 80-90 ℃;

9) and (3) concentrating under reduced pressure: after reverse osmosis concentration, further concentrating the fermentation liquor by reduced pressure concentration to obtain saturated sodium glutamate solution;

10) freezing and crystallizing: crystallizing the obtained saturated solution of sodium glutamate in a low-temperature freezing crystallization tank, and maintaining the temperature at 5-10 ℃;

11) centrifuging and drying.

The preparation method of the soybean meal hydrolysate comprises the following steps: preheating 20% soybean meal solution at 90 deg.C for 10min, hydrolyzing at 40 deg.C, pH3, adding 20000U/g acid protease (calculated on dry soybean meal), and inactivating enzyme when the hydrolysis time is 3 hr.

Example 2

Referring to example 1, the difference is that the alkaline mixture is prepared from 1 mol/L NaOH and 25% ammonia water in a ratio of 1: 1.

Example 3

Referring to example 1, the difference is that the alkaline mixture is prepared from 1 mol/L NaOH and 25% ammonia water in a ratio of 4:6

Example 4

Referring to example 1, except that the feeding ratio of the clarified fermentation broth and 1 mol/L NaOH solution in the monosodium glutamate preparation was 1: 0.5.

Example 5

Referring to example 1, except that the feeding ratio of the clarified fermentation broth and 1 mol/L NaOH solution in the monosodium glutamate preparation was 0.5: 1.

TABLE 1 comparison of L-glutamic acid yield, monosodium glutamate crystal quality and yield in fermentation broth

	L-glutamic acid yield (g/L)	Monosodium glutamate Crystal Mass (g/L)	Yield (%)
				Example 1	181	220.8	122
Example 2	161	189.9	118
				Example 3	153	185	121
Example 4	182	200.3	110
				Example 5	176	198	112

As can be seen from Table 1, the alkaline mixed solution adopted in the fermentation process to replace ammonia water can indeed play a role in relieving the inhibition of ammonium salt, so that the yield of the L-glutamic acid is improved, wherein the alkaline mixed solution prepared by 1 mol/L NaOH solution and ammonia water according to the proportion of 6:4 has the best effect on improving the yield of the L-glutamic acid; in the process of preparing monosodium glutamate, the method that clarified fermentation liquor and 1 mol/L NaOH solution respectively flow into a stirring tank in proportion, are mixed uniformly in the stirring tank and then are rapidly pumped into a decompression concentration tank is adopted for preparation, and the yield of the final product is obviously improved, wherein the ratio of the fermentation liquor to the NaOH solution is 1: the yield of the mixed preparation with the ratio of 1 is the highest, which shows that the ratio has the best effect.

Although the present invention has been described in detail with respect to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made based on the present invention. Accordingly, it is intended that all such modifications and variations as fall within the true spirit of this invention be included within the scope thereof.