CN113636703A

CN113636703A - Method for isoelectric extraction of protein from amino acid wastewater

Info

Publication number: CN113636703A
Application number: CN202110823679.4A
Authority: CN
Inventors: 王小平; 赵兰坤; 侍述志; 张传松; 白红兵; 李武红; 刘刚; 曹连坤
Original assignee: Hulunbeier Northeast Fufeng Biotechnologies Co ltd
Current assignee: Hulunbeier Northeast Fufeng Biotechnologies Co ltd
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2021-11-12

Abstract

The invention belongs to the field of amino acid wastewater treatment, and discloses a method for isoelectric protein extraction of amino acid wastewater, which comprises the following steps: reducing the blood sugar of the amino acid fermentation waste water, adjusting the isoelectric point of the amino acid fermentation waste water to be 3.1-3.2, pumping the adjusted amino acid fermentation waste water into a protein extraction tank, and adding a flocculating agent for flocculation extraction; and (3) compressing the extracted wet protein by a filter press, further extracting solid wet protein, drying the pressed wet protein, then feeding the dried wet protein into a crusher by an air conveying system for crushing to produce a finished product, concentrating the waste water after protein extraction, and spraying, granulating and preparing the fertilizer.

Description

Method for isoelectric extraction of protein from amino acid wastewater

Technical Field

The technology belongs to the field of amino acid wastewater treatment, and particularly relates to a method for isoelectric protein extraction of amino acid wastewater.

Background

The technology for treating the amino acid wastewater is always a hotspot and a difficult point of research, in recent years, the construction and development of the amino acid production industry in China are fast, and the technology becomes a hotspot of the investment of foreign resources and the increase of the economy in China, so that environmental problems such as water resource pollution and the like become keys for restricting the sustainable development of the amino acid production industry.

The fermentation industry in China develops rapidly, in particular to the monosodium glutamate industry. As is known, the large production of monosodium glutamate in China stably stays in the world leadership, and the wastewater contains high-concentration COD and BOD, about 0.6 percent of reducing sugar and 1.0 percent of glutamic acid bacteria. The glutamic acid wastewater mainly comes from residual ion exchange mother liquor for extracting glutamic acid, sewage generated by washing various devices in the production process and condensed water in various processes. The discharge of a large amount of waste liquid and the extrusion and accumulation of waste thalli become a main problem, if glutamic acid waste water is utilized, the method is an important measure combined with environmental protection, not only can fully utilize waste resources, but also can obtain a new product, achieves two purposes at one stroke, has extremely wide application prospect, and is also a problem generally concerned by the majority of monosodium glutamate enterprises.

China is a big country for producing monosodium glutamate, and more than 70 ten thousand tons of monosodium glutamate are produced every year and live at the top of the world. Production of monosodium glutamate

The discharged waste liquid is separated at the medium electric point in the process, the pollution load is high, the quantity is large, and the pollution is serious. According to statistics, each production

1 ton of monosodium glutamate can be used, and about 20 tons of waste liquid can be discharged. Glutamic acid waste water contains a large amount of mycoprotein and

the useful organic matters can be fully utilized, so that the waste is changed into valuable.

The characteristics of the mycoprotein of the glutamic acid waste liquid are as follows: the glutamic acid mycoprotein is a byproduct in the production process of monosodium glutamate

After glutamic acid is generated by glutamic acid producing bacteria, the waste thallus after monosodium glutamate extraction is separated, dried and ground into powder

The single-cell protein is obtained by extracting glutamic acid fermentation broth containing wet thallus about 4%, drying

High quality protein with protein content over 70% can be produced. The glutamic acid mycoprotein is in powder or fine particle shape,

the color of the product is different according to different sugar raw materials used in the fermentation process, and is usually gray white to earthy yellow (brown), if the color of the fed-batch molasses is dark, the product is dark brown to dark brown, has the peculiar slight fragrance of the thallus, and has no foreign odor.

In the production process of monosodium glutamate, glutamic acid strain fermentation is carried out to produce a large amount of glutamic acid, a large amount of tail liquid is obtained after glutamic acid is extracted from fermentation liquor, a large amount of mycoprotein is contained in the tail liquid, if the mycoprotein is not extracted and is directly subjected to slurry spraying granulation, waste is caused, the value of the fermentation tail liquid is reduced, and if the mycoprotein is extracted as a feed, the value of the fermentation tail liquid can be improved. Therefore, it is necessary to extract mycoprotein from the fermentation tail liquid.

The flocculation precipitation method is the most common method for treating wastewater, and the most used method in industry is sodium polyacrylate. Sodium polyacrylate is selected as the flocculating agent because the sodium polyacrylate is low in price and stable in effect. The synthesized organic polymeric flocculant has the advantages of small dosage, strong flocculation capability, high precipitation speed and the like, and has wide application prospect in the field of water treatment. There are many factors affecting the effect of flocculation and precipitation, such as pH, temperature, etc., and how to adjust and optimize to obtain the optimal solution is difficult.

Disclosure of Invention

In order to solve the problems of poor flocculation effect and low extraction rate of a flocculating agent in the prior art of extracting mycoprotein from amino acid fermentation waste liquid, the invention provides a method for isoelectric extraction of protein from amino acid waste water.

The invention is realized by the following technical scheme:

a method for isoelectric extraction of protein from amino acid wastewater comprises the following steps:

carrying out blood sugar reduction treatment on the amino acid fermentation wastewater, then adjusting the protein concentration in the feed liquid to 1200-1600mg/L, slowly adding concentrated sulfuric acid, adjusting the isoelectric point of the concentrated sulfuric acid to be 3.1-3.2, then pumping the adjusted amino acid fermentation wastewater into a protein extraction tank, adding a flocculating agent for flocculation extraction, wherein the concentration of the flocculating agent is 1-3 per mill (w/v), heating to 50 ℃, stirring under the heat preservation condition for 10-20min, then cooling to 35 ℃, and precipitating for 2.0-4.0 h under the heat preservation condition; and (3) compressing the extracted wet protein by a filter press, further extracting solid wet protein, drying the pressed wet protein, then feeding the dried wet protein into a crusher by an air conveying system for crushing to produce a finished product, concentrating the waste water after protein extraction, and spraying, granulating and preparing the fertilizer.

Preferably, the flocculant is sodium acrylate.

Preferably, the pH is 3.15.

Preferably, the protein concentration is 1400mg/L.

Preferably, the concentration of the flocculant is 2% o (w/v).

Preferably, the precipitation time is 3.0h.

Preferably, the stirring time is 15 min.

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

the mycoprotein is the comprehensive utilization of waste resources, has relatively low cost and outstanding economic benefit, and makes full use of

Changes waste into valuable, so that the development and utilization of the glutamic acid wastewater have wide prospects.

The amino acid fermentation tail liquid contains a large amount of mycoprotein, which has high nutritive value, and the mycoprotein contains thallus

If the protein can be fully utilized, the method not only can protect the environment and reduce the influence of the factory wastewater on the environment, but also can reduce the influence of the factory wastewater on the environment

And can also relieve the problem of shortage of protein feed in China to a great extent, and simultaneously reduce cost and improve efficiency of enterprises

Has important significance. The invention explores a group of optimum combinations by continuously researching influencing factors and optimizing and improving parameter steps.

And in addition, the temperature is raised while the protein flocculation is fully separated out, so that the solid protein is separated out to the maximum extent, the extracted wet protein is compressed by a filter press and then is further extracted, the pressed wet protein is dried and then enters a crusher through an air conveying system to be crushed to produce a finished product, and the waste water after the protein extraction is concentrated and then is subjected to spray granulation to prepare the fertilizer. Effectively solves the problem of waste water discharge in the traditional amino acid production.

Drawings

FIG. 1: a process route diagram of the invention;

FIG. 2: influence of pH on the protein precipitation rate of the amino acid fermentation waste liquid;

FIG. 3: influence of temperature on protein precipitation rate of amino acid fermentation waste liquid

FIG. 4: influence of precipitation time on protein precipitation rate in the amino acid fermentation waste liquid;

FIG. 5: influence of protein concentration in the amino acid fermentation waste liquid on precipitation rate.

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

Experimental Material

The wastewater mainly comprises wastewater generated after amino acid is extracted in each workshop

Experimental procedure

Effect of pH on protein precipitation Rate of amino acid fermentation wastewater

As can be seen from FIG. 2, the precipitation rate of protein in the supernatant of amino acid fermentation wastewater was found to be 3.1 to 3.2 pH

The highest. According to the principle that the water solubility of protein at isoelectric point is minimum, the protein and the like in the amino acid fermentation wastewater

The electric point is between 3.1 and 3.2. At isoelectric point, the amount of protein precipitated is greatest, and the protein particles are physically numerous

Properties such as bound water, particle size, osmotic pressure, etc. become small, facilitating filtration of the protein suspension.

The amino acid fermentation wastewater is high-concentration organic wastewater, and if the pH value is too low, the wastewater has precipitation effect and the recovered eggs

The quality of white matter is poor, so when the influence factor research of protein recovery by acid precipitation is carried out subsequently, the selection is carried out

The orthogonal experiments were performed at three levels of pH 3.10, 3.15, and 3.20.

2. Influence of wastewater temperature on protein precipitation rate in amino acid fermentation wastewater

As can be seen from FIG. 3, the protein precipitation rate increased and then decreased with increasing temperature, at 25 deg.C and 35 deg.C

The precipitation rate is maximal and then the protein precipitation rate is slightly decreased. Egg separated out at a temperature of more than 45 deg.C

White matter is suspended in the wastewater and difficult to precipitate. This is probably due to the fact that the protein precipitates and then binds to water at high temperature

The protein is swelled, resulting in poor precipitation and reduced protein precipitation rate. Comprehensive consideration of amino acid plants

The actual situation of the production wastewater selects three levels of 25, 30 and 35 ℃ for orthogonal test.

3. Influence of precipitation time on protein precipitation rate of amino acid fermentation wastewater

As is clear from FIG. 4, the protein precipitation rate tended to increase gradually and then decrease sharply with the increase of the precipitation time.

After stabilization, the protein concentration of the stock solution is increased due to the high concentration of organic matters in the wastewater and the easy microbial contamination

In addition, the protein precipitation rate is reduced. Comprehensive test results, selecting precipitation time of 2.5, 3.0 and 3.5h

Orthogonal experiments were performed horizontally.

4. Influence of protein concentration in amino acid fermentation wastewater on protein precipitation rate

As can be seen from FIG. 5, the protein precipitation rate of the amino acid fermentation wastewater increased as the protein concentration increased because

After the amino acid fermentation wastewater is precipitated, the concentration of residual protein in the wastewater is not greatly different, so that the amino acid is generated

The higher the protein content in the fermentation wastewater, the higher the precipitation rate. The protein concentration of the amino acid fermentation wastewater is

The protein precipitation rate was the best after 1200(3:2500) mg/L. The comprehensive test results show that the protein concentration of the amino acid fermentation wastewater is selected to be 1000(1:1000), 1200(3:2500) and 1400(7:5000) mg/L

And (4) cross-linking test.

5. High heat temperature: the temperature of the mycoprotein is controlled to be 40 ℃, 45 ℃, 50 ℃, 55 ℃ and 60 ℃, the experiment is carried out under the condition that the concentration of the flocculating agent is 2 per mill, and the temperature gradient difference is 5 ℃. And (5) observing the bacterial degeneration flocculation effect and recording data.

Under the condition that the concentration of the fixed flocculating agent is 2 per mill, and the temperature is 40 ℃ and 45 ℃, the flocculation volume is loose, and the flocculation effect is poor. When the temperature for extracting the mycoprotein reaches 50 ℃, 55 ℃ and 60 ℃, the flocculation effect starts to have obvious change, and the flocculation group starts to become large and solid, and the flocculation effect is good. From this, it is found that the flocculation effect is best when the heating temperature is 50 ℃.

High heat retention time: the heating maintaining time is divided into 5min, 10min, 15min, 20min and 25 min.

Performing experiments with different time and 5min time gradient difference, and observing the transmittance of the supernatant and its transmittance in 10min

The volume of the inner filtrate was measured and the data was recorded.

Influence of Heat Retention time

The temperature was maintained at 50 ℃ at a flocculant concentration of 2% o, and the heat retention time was varied, the results are shown in table 1 below.

TABLE 1

As can be seen from the above table, the transmittance of the supernatant and the filtering effect thereof are improved with the gradual increase of the heating time

The better the result, but at 20min, although the supernatant transmittance still increased, but its filtration volume had a very obvious decrease trend; at 25min, the supernatant transmittance and the filtration volume were all reduced. The larger the filtration volume, the more the mycoprotein flocculated and precipitated. The filtration volume becomes smaller, which means that the mycoprotein is in the shape of flowing flocculent, and the heating time is too long, so that the flocculation group which is originally formed is dissolved and mixed with the aqueous solution, the flocculation group cannot be formed, and the water and the flowing mycoprotein are difficult to separate, so the volume filtered is small. From this, it was found that the supernatant was most clear and the filtration effect was best when the heating time was 15 min.

6. Design of orthogonal experiments

Screening out wood according to the single-factor test result of protein in amino acid fermentation wastewater recovered by isoelectric point method

The experimental conditions under which the potato protein precipitation rate was highest were subjected to an orthogonal test. Protein isoelectric point method for amino acid fermentation wastewater

The orthogonal experimental design is shown in table 2.

TABLE 2

Taking precipitation temperature, precipitation time, concentration and pH value as factors to be considered, and adopting L9 to carry out orthogonal test

The results are analyzed and shown in Table 3.

TABLE 3

7. Results and analysis

Comparing the magnitude of the range R, the major and minor sequences affecting protein recovery are D > C > B > A, i.e., waste

The pH of the solution is most affected, followed by the protein concentration in the system and the time, with the least effect on temperature. Isoelectric point

The optimal process conditions for recovering the protein in the amino acid fermentation wastewater by the method are as follows: A3B2C3D2, namely at 35 ℃,

The precipitation time was 3.0h, the concentration was 1400(7:5000) mg/L, pH with a value of 3.15, and none of the orthogonal tests

The precipitation rate under this condition, therefore, the test result under this condition needs to be verified, and the verification result is 98.3%.

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.

Claims

1. A method for isoelectric extraction of protein from amino acid wastewater comprises the following steps:

2. The method of claim 1, wherein the flocculant is sodium acrylate.

3. The method of claim 1, wherein the pH is 3.15.

4. The method of claim 1, wherein the protein concentration is 1400mg/L.

5. The method of claim 1, wherein the concentration of the flocculant is 2% o (w/v).

6. The method according to claim 1, characterized in that the precipitation time is 3.0h.

7. The method according to claim 1, wherein the stirring time is 15 min.