阅读说明：本技术 一种古龙酸的提取方法 (Extraction method of gulonic acid ) 是由 慕金凤 王良 马晓军 朱娜 于 2020-12-17 设计创作，主要内容包括：本发明涉及一种古龙酸的提取方法,其工艺步骤为：将古龙酸钠发酵液依次采用陶瓷微滤膜过滤、平板超滤膜复滤后用阳离子交换树脂离交得到古龙酸溶液,然后将古龙酸溶液用高压纳滤膜浓缩、双效或三效蒸发器蒸发浓缩,所得浓缩液中加入古龙酸结晶母液,入连续单效蒸发器中浓缩,后降温结晶、离心分离、干燥即可得古龙酸。本发明同常规超滤法提取工艺相比,有效提高结晶收率,且工艺简单,操作简便,生产成本低。(The invention relates to a method for extracting gulonic acid, which comprises the following process steps: filtering the gulonic acid sodium fermentation liquor by adopting a ceramic microfiltration membrane and a flat ultrafiltration membrane in sequence, then performing ion exchange by using cation exchange resin to obtain a gulonic acid solution, concentrating the gulonic acid solution by using a high-pressure nanofiltration membrane, and performing evaporation concentration by using a double-effect or triple-effect evaporator, adding a gulonic acid crystallization mother liquor into the obtained concentrated solution, concentrating the gulonic acid solution in a continuous single-effect evaporator, and then cooling, crystallizing, centrifugally separating and drying to obtain the gulonic acid. Compared with the conventional ultrafiltration extraction process, the method has the advantages of effectively improving the crystallization yield, along with simple process, simple and convenient operation and low production cost.)

1. A gulonic acid extraction method is characterized by comprising the following process steps: filtering the gulonic acid sodium fermentation liquor by adopting a ceramic microfiltration membrane and filtering again by using a flat ultrafiltration membrane in sequence, then exchanging by using cation exchange resin to obtain a gulonic acid exchange solution, then concentrating the gulonic acid exchange solution by using a high-pressure nanofiltration membrane, evaporating and concentrating by using a double-effect or triple-effect evaporator, adding a gulonic acid crystallization mother liquor into the obtained concentrated solution, concentrating in a continuous single-effect evaporator, cooling, crystallizing, centrifugally separating and drying to obtain the gulonic acid.

2. The method for extracting gulonic acid as claimed in claim 1, wherein the pressure of the inlet membrane is controlled to be 0.30-0.35 MPa, the pressure of the outlet membrane is controlled to be 0.20-0.25 MPa, the temperature is controlled to be 30-40 ℃ and the volume of the concentrated solution is controlled to be 5-10% of the volume of the original solution during the filtration of the ceramic microfiltration membrane and the re-filtration of the flat ultrafiltration membrane.

3. The method for extracting gulonic acid according to claim 1, wherein the gulonic acid exchange solution is concentrated to 30-60% of the volume of the stock solution by using a high pressure nanofiltration membrane.

4. The extraction method of gulonic acid according to claim 1, wherein the double-effect evaporator or the triple-effect evaporator is concentrated until the specific gravity of the concentrated solution is 1.1-1.3.

5. The extraction method of gulonic acid according to claim 1, wherein the volume ratio of the gulonic acid double-effect or triple-effect concentrated solution to the gulonic acid primary crystallization mother solution is 5-10: 1.

6. The process for extracting gulonic acid as claimed in claim 1, wherein said continuous single effect evaporator is concentrating until the specific gravity of the concentrated solution is 1.38-1.45.

7. The extraction method of gulonic acid as claimed in claim 1, wherein the crystallization by cooling is performed by slowly cooling the concentrated solution obtained by single effect concentration to 0-5 ℃.

Technical Field

The invention relates to an antibiotic refining technology, in particular to a gulonic acid extraction method.

Background

2-keto-L-gulonic acid (KGA for short) is an important intermediate for producing vitamin C in the pharmaceutical industry, and the improvement of the quality of the 2-keto-L-gulonic acid has a crucial influence on the inherent quality of the vitamin C (including baking extinction, crystal form completeness, shelf life extension and the like), and is also an important means for reducing the cost, improving the quality and increasing the economic benefit.

The traditional gulonic acid extracting process is to exchange sodium gulonate generated by two-step fermentation of sorbitol with cation exchange resin, and then to prepare gulonic acid by concentration, crystallization, washing and drying. The production process has the advantages of longer flow, more stable and reliable technology, larger gulonic acid loss, lower yield and more consumed regenerated acid and alkali in the production process. With the development and progress of chemical separation technology in recent years, scientific researchers in China have made some attacks and customs on the gulonic acid extraction technology, and made some progress: 1. the isoelectric point treatment method is that impurities (including mycoprotein, culture medium used up, nucleic acid and the like) in gulonic acid mash generated by two-step fermentation of vitamin C are removed by isoelectric point adjustment, heating sedimentation and high-speed centrifugation, so as to achieve the purposes of improving the extraction yield and the product quality. 2. And (2) an ultrafiltration method, namely performing ultrafiltration on gulonic acid mash generated by two-step fermentation of vitamin C by using an ultrafiltration membrane, exchanging dialysate by using cation exchange resin to obtain a gulonic acid solution, performing nanofiltration concentration, concentration by using a double-effect evaporator or a triple-effect evaporator, and crystallization after concentration by using a continuous single-effect evaporator, separating and drying to obtain the gulonic acid. Among them, the ultrafiltration method is widely used in the separation, concentration and purification of bioactive substances because of its characteristics of low energy consumption, high efficiency, low operation temperature, difficult inactivation of bioactive substances, etc. However, the extraction of gulonic acid by the ultrafiltration method has the following problems: 1) a large amount of impurities such as residual culture medium, protein and the like exist in the gulonic acid sodium fermentation liquor, ultrafiltration membrane separation is directly adopted without other membrane pre-filtration, the risk of pollution of the ultrafiltration membrane is increased, the membrane utilization rate is reduced, the dialysate is large in size, the concentration is prolonged, the gulonic acid is degraded at high temperature, the impurities are increased, and the extraction yield is reduced. 2) The concentration specific gravity of the gulonic acid is a main factor influencing the primary crystallization yield of the gulonic acid. In the traditional process, the gulonic acid exchange solution passes through a high-pressure nanofiltration membrane and is concentrated by three-effect, double-effect and single-effect, but the specific gravity of the concentrated solution in a single-effect concentrator is too high (more than 1.38), so that the flowability of the concentrated solution is influenced, and the normal operation of single-effect concentration equipment is further influenced.

Therefore, the extraction process of gulonic acid still needs to be optimized, and is always an important subject for the research of vitamin C manufacturers.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the method for extracting the gulonic acid, which effectively improves the crystallization yield, and has the advantages of simple process, simple and convenient operation and low production cost.

The technical scheme adopted for realizing the aim of the invention is as follows:

a gulonic acid extraction method is characterized by comprising the following process steps: filtering the gulonic acid sodium fermentation liquor by adopting a ceramic microfiltration membrane and filtering again by using a flat ultrafiltration membrane in sequence, then exchanging by using cation exchange resin to obtain a gulonic acid exchange solution, then concentrating the gulonic acid exchange solution by using a high-pressure nanofiltration membrane, evaporating and concentrating by using a double-effect or triple-effect evaporator, adding a gulonic acid crystallization mother liquor into the obtained concentrated solution, concentrating in a continuous single-effect evaporator, cooling, crystallizing, centrifugally separating and drying to obtain the gulonic acid.

When the ceramic microfiltration membrane is used for filtering and the flat plate ultrafiltration membrane is used for re-filtering, the membrane inlet pressure is controlled to be 0.30-0.35 MPa, the membrane outlet pressure is controlled to be 0.20-0.25 MPa, the temperature is 30-40 ℃, and the volume of a concentrated solution is controlled to be 5-10% of the volume of a stock solution when the ceramic microfiltration membrane is used for filtering.

And concentrating the gulonic acid exchange solution to 30-60% of the volume of the stock solution by using a high-pressure nanofiltration membrane.

And concentrating the double-effect evaporator or the triple-effect evaporator until the specific gravity of the concentrated solution is 1.1-1.3.

The volume ratio of the gulonic acid double-effect or triple-effect concentrated solution to the gulonic acid primary crystallization mother liquor is 5-10: 1.

When the continuous single-effect evaporator is used for concentration, the continuous single-effect evaporator is concentrated until the specific gravity of the concentrated solution is 1.38-1.45.

And the cooling crystallization is to slowly cool the concentrated solution obtained by single-effect concentration to 0-5 ℃ for crystallization.

Compared with the conventional ultrafiltration extraction process, the method has the following technical advantages:

1) the method adopts the ceramic microfiltration membrane and the flat ultrafiltration membrane to filter the gulonic sodium fermentation liquor in a grading way, the ceramic microfiltration membrane filters most residual culture medium and macromolecular protein, the flat ultrafiltration membrane is adopted to filter the dialysate of the ceramic microfiltration membrane, the flux of the ultrafiltration membrane is improved by more than 2 times compared with that of the flat ultrafiltration membrane which is directly used for filtering the gulonic sodium fermentation liquor, the utilization rate of the flat ultrafiltration membrane is improved, the service life of the ultrafiltration membrane is prolonged, and the cleaning frequency is reduced. And the protein content of the gulonic acid exchange solution is fundamentally reduced by stage filtration, and the quality of a gulonic acid wet product is improved.

2) According to the invention, the gulonic acid crystallization mother liquor is added into the gulonic acid triple-effect concentrated solution and then concentrated by using the single-effect concentrator, so that the total volume of the mother liquor is fundamentally reduced, the recovery time of the gulonic acid crystallization mother liquor is shortened, the high-temperature degradation of the gulonic acid is reduced, and the extraction yield of the gulonic acid is improved.

Compared with the conventional extraction process of gulonic acid, the method provided by the invention comprises the following specific operation steps:

A. control group: filtering gulonic acid fermentation liquor with a flat ultrafiltration membrane (the membrane inlet pressure is 0.32MPa, the membrane outlet pressure is 0.22MPa, and the temperature is lower than 40 ℃), feeding the dialysate into cation exchange resin (the pH of the exchange liquid is less than or equal to 1.7), concentrating the dialysate by a high-pressure nanofiltration concentration membrane (the concentration multiple is 1.5-3.0), concentrating the dialysate by a double-effect evaporator and a triple-effect evaporator (the concentration proportion is 1.1-1.3), concentrating the dialysate by a continuous single-effect evaporator (the proportion is 1.3-1.4), slowly cooling the concentrate to 0-5 ℃, crystallizing and centrifuging to obtain a gulonic acid wet product.

B. The invention group: gulonic acid fermentation liquor-ceramic microfiltration membrane (membrane inlet pressure 0.32MPa, membrane outlet pressure 0.22MPa and temperature <40 ℃) -flat ultrafiltration membrane filtration (membrane inlet pressure 0.32MPa, membrane outlet pressure 0.22MPa and temperature <40 ℃) -dialysate inlet cation exchange resin (pH of exchange liquid is less than or equal to 1.7) -high-pressure nanofiltration concentration membrane concentration (concentration multiple of 1.5-3.0) -double-effect evaporator, concentration of triple-effect evaporator (concentration specific gravity of 1.1-1.3) -gulonic acid triple-effect concentrated solution (V): and (3) gulonic acid one mother (V) = 5-10: 1-continuous single-effect evaporator concentration (specific gravity is 1.35-1.45), slowly cooling the concentrated solution to 0-5 ℃, and crystallizing and centrifuging to obtain a gulonic acid wet product.

The results of 10 experimental batches were collected and shown in Table 1.

TABLE 1 parameters relating to the different ways of extraction of gulonic acid

Group number	Flat sheet membrane flux L/h m-2	Protein mg/ml of the exchange solution	Triple effect concentrate (V): mother liquor (V)	The content of finished gulonic acid product is%	Sodium salt of finished product%	The extraction yield is%
							Control group	102-125	0.2-0.6	Is free of	89-90	0.02-0.04	88-90
Invention group	299-339	0.1-0.3	5~10:1	90-92	0.01-0.04	91-93

The above results show that: the yield of the gulonic acid in the invention is 2-4% higher than that of a control group, the content of the gulonic acid is improved by 1-3%, and the flux of a flat ultrafiltration membrane is improved by 2-3 times.

Detailed Description

The invention is illustrated below by way of examples, which are to be understood as being illustrative and not limiting. The scope and core content of the invention are to be determined by the claims.

Example 1:

(1) membrane filtration: 317L of gulonic acid fermentation liquor with the content of 122.88mg/ml, the light transmittance of 0.92 percent and the protein of 7.15mg/ml is taken. And (3) filtering by adopting a ceramic microfiltration membrane, controlling the membrane inlet pressure to be 0.30MPa, the membrane outlet pressure to be 0.20 MPa and the temperature to be 30-35 ℃, and filtering until the volume of the concentrated liquid is about 8% of the volume of the ceramic membrane dialysate.

Filtering the obtained dialysate with flat ultrafiltration membrane (pore diameter of 2 ten thousand molecular weight), controlling the pressure of inlet membrane to 0.32MPa and the pressure of outlet membrane to 0.22MPa, controlling the filtering temperature to 35-40 deg.C, and filtering again until the volume of concentrated liquid is about 10% of that of the dialysate of ceramic membrane, and the average membrane flux is 338.4L/h × m^-2。

(2) Ion exchange conversion: and (3) putting the dialysate filtered by the flat ultrafiltration membrane into cation exchange resin, controlling the pH of the exchange liquid to be less than or equal to 1.7, controlling the exchange capacity of the resin to be 0.216g/ml, controlling the transmittance of the exchange liquid to be 99.2%, and controlling the protein content to be 0.11 mg/ml.

(3) Concentration and crystallization: concentrating the obtained gulonic acid exchange solution by using a high-pressure nanofiltration concentration membrane until the volume of the concentrated solution is 50% of that of the ion exchange solution, further concentrating by using a triple-effect evaporator until the specific gravity is 1.25, and concentrating the gulonic acid triple-effect concentrated solution (V): mixing the gulonic acid crystallization mother liquor (V) according to the ratio of 8:1, then concentrating by adopting a continuous single-effect evaporator until the specific gravity is 1.38, further slowly cooling to 5 ℃, centrifuging and drying to obtain a gulonic acid finished product.

(4) And (3) detection: the detection result shows that the content of the finished gulonic acid product is 90.3 percent, the content of the sodium salt is 0.01 percent, and the calculation yield is 91.32 percent.

Example 2:

(1) membrane filtration: 557.9L of gulonic acid fermentation liquor with the content of 129.2mg/ml, the transmittance of 1.03 percent and the protein content of 6.52 mg/ml is taken. Filtering with ceramic microfiltration membrane under the conditions of membrane inlet pressure of 0.35 MPa, membrane outlet pressure of 0.25 MPa and temperature of 30-35 deg.C until the volume of concentrated solution is about that of ceramic membrane dialysate5.3% of the total. Filtering the dialysate with flat ultrafiltration membrane (pore diameter 2 ten thousand molecular weight), controlling the pressure of inlet membrane at 0.32MPa and the pressure of outlet membrane at 0.22MPa, controlling the filtering temperature at 33-38 deg.C, and filtering again until the volume of concentrated liquid is about 9.5% of that of the dialysate of ceramic membrane, and the average membrane flux is 329.3L/h m^-2。

(2) Ion exchange conversion: and (3) putting the flat membrane dialysate into cation exchange resin, controlling the pH of the exchange liquid to be less than or equal to 1.7, controlling the exchange capacity of the resin to be 0.228g/ml, controlling the transmittance of the exchange liquid to be 99.5 and controlling the protein content to be 0.3 mg/ml.

(3) Concentration and crystallization: concentrating the exchange solution by using a high-pressure nanofiltration membrane until the volume of the concentrated solution is 58% of the volume of the exchange solution, further concentrating by using a double-effect evaporator until the specific gravity is 1.1, and mixing the gulonic acid double-effect concentrated solution (V): mixing the gulonic acid crystallization mother liquor (V) according to the ratio of 10:1, then concentrating by adopting a continuous single-effect evaporator until the specific gravity is 1.45, and further slowly cooling to 0 ℃ for centrifuging to obtain a gulonic acid finished product.

(4) And (3) detection: the content of the gulonic acid finished product is detected to be 91.2 percent, the content of the sodium salt is detected to be 0.04 percent, and the calculated yield is 92.65 percent.

Example 3:

(1) two-stage membrane filtration: 530L of gulonic acid fermentation liquor with the content of 132.33mg/ml, the light transmittance of 1.25 percent and the protein of 6.46 mg/ml is taken. And (3) filtering by adopting a ceramic microfiltration membrane, controlling the membrane inlet pressure to be 0.32MPa, the membrane outlet pressure to be 0.22MPa and the temperature to be 30-35 ℃, and filtering until the volume of the concentrated liquid is about 5.8% of the volume of the ceramic membrane dialysate. Filtering the dialysate with flat ultrafiltration membrane (pore diameter 2 ten thousand molecular weight), controlling the pressure of inlet membrane at 0.32MPa and the pressure of outlet membrane at 0.22MPa, controlling the filtering temperature at 35-39 deg.C, and filtering again until the volume of concentrated liquid is about 8.2% of that of the dialysate of ceramic membrane, and the average membrane flux is 299.6L/h m^-2。

(2) Ion exchange conversion: and (3) putting the flat membrane dialysate into cation exchange resin, controlling the pH of the exchange liquid to be less than or equal to 1.7, controlling the exchange capacity of the resin to be 0.239g/ml, controlling the transmittance of the exchange liquid to be 100 and controlling the protein content to be 0.21 mg/ml.

(3) Concentration and crystallization: concentrating the exchange solution by using a high-pressure nanofiltration membrane until the volume of the concentrated solution is 30% of the volume of the exchange solution, further concentrating by using a triple-effect evaporator until the specific gravity is 1.3, and mixing the gulonic acid triple-effect concentrated solution (V): mixing the gulonic acid crystallization mother liquor (V) according to the ratio of 5:1, concentrating by adopting a continuous single-effect evaporator until the specific gravity is 1.43, and then slowly cooling to 2 ℃ for centrifuging to obtain a gulonic acid finished product.

(4) And (3) detection: the content of the finished gulonic acid product is detected to be 92 percent, the content of the sodium salt is detected to be 0.018 percent, and the calculated yield is 93.0 percent.

Comparative example:

(1) flat membrane filtration: 502L of gulonic acid fermentation liquor with the content of 128.45mg/ml, the light transmittance of 1.35 percent and the protein of 5.38 mg/ml is taken. Filtering with flat ultrafiltration membrane (pore diameter of 2 ten thousand molecular weight), controlling inlet pressure of 0.34 MPa and outlet pressure of 0.23 MPa, controlling filtering temperature of 32-39 deg.C, filtering until the volume of concentrated liquid is about 7.6% of that of ceramic membrane dialysate, and average membrane flux is 115.5L/h m^-2。

(2) Ion exchange conversion: and (3) putting the flat membrane dialysate into cation exchange resin, controlling the pH of the exchange liquid to be less than or equal to 1.7, controlling the exchange capacity of the resin to be 0.211g/ml, controlling the transmittance of the exchange liquid to be 98 and controlling the protein content to be 0.5 mg/ml.

(3) Concentration and crystallization: and concentrating the exchange liquid by adopting a high-pressure nanofiltration membrane until the volume of the concentrated liquid is 45% of that of the exchange liquid, then concentrating by adopting a triple-effect evaporator until the specific gravity is 1.3, concentrating by adopting a continuous single-effect evaporator until the specific gravity is 1.38, and then slowly cooling to 0 ℃ for centrifugation to obtain a gulonic acid finished product.

(4) And (3) detection: the content of the finished gulonic acid product is 89.7 percent, the content of the sodium salt is 0.03 percent and the calculated yield is 89.8 percent.