阅读说明：本技术 一种除γ-氨基丁酸转化液颜色的方法 (Method for removing color of gamma-aminobutyric acid conversion solution ) 是由 王元秀 闫朝阳 丁良 于 2020-05-09 设计创作，主要内容包括：本发明公开了一种除γ-氨基丁酸(γ-aminobutyric acid,GABA)转化液颜色的方法,属于生物技术领域。所述GABA转化液是以短乳杆菌为GABA生产菌种,使用加入L-谷氨酸钠、曲拉通、磷酸吡哆醛的乙酸-乙酸钠缓冲溶液作为转化体系,采用全细胞转化法制得。本发明的除GABA转化液颜色的方法,成本低,活性炭用量少并且可以再生重复利用,省时,污染少,清除率高,工艺简单,溶液中GABA的损失率低。(The invention discloses a method for removing color of gamma-aminobutyric acid (GABA) conversion liquid, and belongs to the technical field of biology. The GABA conversion solution is prepared by using lactobacillus brevis as GABA production strains, using acetic acid-sodium acetate buffer solution added with L-sodium glutamate, triton and pyridoxal phosphate as a conversion system and adopting a whole-cell conversion method. The method for removing the color of the GABA conversion solution has the advantages of low cost, small using amount of the activated carbon, regeneration and reutilization, time saving, less pollution, high clearance rate, simple process and low GABA loss rate in the solution.)

1. A method for removing the color of gamma-aminobutyric acid conversion liquid comprises the following steps:

preparing gamma-aminobutyric acid (GABA) conversion solution by using whole cell conversion method

Taking lactobacillus brevis as GABA production strain, centrifuging cultured lactobacillus brevis for 48 h, collecting thallus, adding acetic acid-sodium acetate buffer solution containing L-sodium glutamate, triton and pyridoxal phosphate as a conversion system, and performing conversion culture at 30 ℃ for 24-72 h to obtain GABA conversion solution;

② removal of color from GABA conversion liquid

Heating the GABA conversion solution prepared firstly in a boiling water bath for 10 min, centrifuging to obtain a supernatant, adjusting the pH to 5.00-5.20 by using a glacial acetic acid solution, adding activated carbon according to a solid-to-liquid ratio of 1:50-1:100 for decoloring, adsorbing at the decoloring temperature of 30 ℃ for 5-15 min, and performing suction filtration to obtain colorless or yellowish filtrate which is the GABA decoloring conversion solution.

2. The method for removing the color of transformed liquid of gamma-aminobutyric acid according to claim 1, wherein the whole cell transformation method comprises using Lactobacillus brevis as GABA producing strain, inoculating the strain with a mass fraction of 18-22 g/L, using acetic acid-sodium acetate buffer solution as transformation system, and transforming at 30 ℃ for 24-72 h to obtain GABA transformed liquid.

3. The method according to claim 1, wherein the buffer solution is acetic acid-sodium acetate buffer solution containing 0.1% triton, 0.1% pyridoxal phosphate, 6-7% sodium L-glutamate, and pH 4.2-4.6.

4. The method for removing the color of the gamma-aminobutyric acid conversion solution as set forth in claim 1, wherein the centrifugation is performed at 8000 rpm at 4 ℃ for 15 min.

5. The method for removing the color of gamma-aminobutyric acid conversion solution as set forth in claim 1, wherein the glacial acetic acid content of the glacial acetic acid solution is 99%.

6. The method for removing color of gamma-aminobutyric acid conversion solution as set forth in claim 1, wherein the diameter of micropores on the surface of the activated carbon is between 9 and 20 nm.

7. The method for removing the color of the gamma-aminobutyric acid conversion solution according to claim 1, wherein the GABA decoloring conditions comprise adding activated carbon according to a solid-to-liquid ratio of 1:50 to 1:100, and decoloring the solution at pH 5.00 to 5.20 and at 30 ℃ for 5 to 15 min.

8. The method for removing the color of the gamma-aminobutyric acid conversion solution according to claim 1, wherein the conversion solution turns colorless or yellowish after the GABA is decolored, the loss rate of GABA is between 6% and 10%, the activated carbon used in the decoloring process can be recycled, and the loss rate of the activated carbon is between 2% and 6%.

Technical Field

The invention relates to a method for removing color of gamma-aminobutyric acid (GABA) conversion liquid.

Background

GABA is a natural non-protein amino acid and widely distributed in animals, plants and microorganisms. At present, GABA solid is prepared at home and abroad mostly by a crystallization method, but before the crystallization treatment of GABA conversion liquid, the color of the solution seriously influences the quality of GABA crystal crystals, so the decoloring treatment is required.

The traditional decoloring method comprises five decoloring modes of activated carbon decoloring, macroporous adsorption resin, ion exchange resin, hydrogen peroxide, gel chromatography and the like, wherein the decoloring method of GABA conversion solution in industrial application mainly comprises 2 decoloring modes, namely activated carbon decoloring and macroporous adsorption resin decoloring, and the application of the decoloring modes in actual production is different.

Macroporous adsorption resin is a new type of non-ionic polymer adsorbent, and is usually polymerized from divinylbenzene, styrene or methacrylic acid. Wuqiaoyuo et al (Wuqiaoyou, xie clever, Gaoyixian, Jiang donghua. the decolorization and purification process of gamma-aminobutyric acid in lactobacillus brevis fermentation liquor discussing [ J ]. fermentation science and technology communication, 2015,44(03): 12-17.) have studied the effect of adsorbing GABA conversion solution by 6 kinds of macroporous resin and activated carbon, and found that the decolorization effect of macroporous resin ADS-7 and activated carbon is the best. However, the optimum decolorization process of activated carbon is not summarized, and the loss rate of GABA exceeds 9%; yellow and handsome et al (yellow and handsome, mele and, hul, maojiangwei, liushiwang, lie on the level, prosperous, xu shui, wuhui. flocculation and decoloration process research of gamma-aminobutyric acid fermentation broth [ J ]. food industry science and technology, 2009,30(07):257 + 259+ 269.) use chitosan as flocculant, use macroporous resin SD300 to decolorize GABA fermentation broth, obtain decolorization pH and decolorization temperature after optimizing are pH 5.0 and 25 ℃ respectively, but use GABA that SD300 decolorization obtained, can not be applied to the food industry;

activated carbon is a common decolorant in industry, and the excellent adsorption performance of the activated carbon is mainly from a self-developed pore structure. The homoeosin (homoeosin, high yield gamma-aminobutyric acid lactobacillus fermentation condition optimization and separation and purification process research [ D ]. Zhejiang university, 2013.) finds that the decolorization effect of the activated carbon is better than that of the macroporous adsorption resin, but the GABA yield is relatively low because the activated carbon is used for too long adsorption time. High sensitivity and the like (high sensitivity, kojiu Chongyan, duckweed, Liu Meng millet, Huang Jian faithful. research on decolorization process of gamma-aminobutyric acid conversion solution produced by whole cell catalysis [ J ] Fujian agricultural science and technology, 2020(01): 17-23.) the decolorization method of combining activated carbon with resin chromatography can effectively remove the color of the conversion solution, and the recovery rate of GABA also reaches 98%, but GABA obtained by macroporous resin decolorization still cannot be used in the food industry, so the application of GABA is more limited compared with GABA obtained by only using the activated carbon decolorization method.

The GABA decoloring method comprises the following steps: the decoloring modes such as ion exchange resin, hydrogen peroxide decoloring, gel chromatography and the like are difficult to be applied in the field of GABA industrial production in a large scale, the macroporous adsorption resin decoloring method can be applied to the production of non-food-grade GABA, certain limitation exists in application, GABA obtained by decoloring with active carbon does not have any application limitation, and meanwhile, the decoloring process is low in energy consumption, the active carbon can be recycled, the environmental pollution is low, the safety is high, the cost is low, and therefore, the macroporous adsorption resin decoloring method is very suitable for being applied in the production of food-grade GABA in a large scale.

Disclosure of Invention

The invention aims to solve the problem of lack of a food-grade GABA decoloring production process, and provides a method for removing the color of GABA conversion liquid, which has the advantages of simple equipment, environmental protection, low cost and high decoloring efficiency, the GABA decoloring conversion liquid obtained by the method is colorless or yellowish, the GABA loss rate in the decoloring conversion liquid is 6-10%, activated carbon used in the decoloring process can be recycled, and the activated carbon loss rate is 2-6%.

When the color of the GABA conversion solution is removed, the concentration of GABA in the conversion solution is higher than 50 g/L, the loss rate of GABA in the decoloration conversion solution is between 6 and 10 percent, and the loss rate of activated carbon is between 2 and 6 percent.

The invention relates to a method for removing the color of gamma-aminobutyric acid conversion liquid, which comprises the following steps:

preparing GABA transformation liquid by whole cell transformation method

Taking lactobacillus brevis as GABA production strain, centrifuging cultured lactobacillus brevis for 48 h, collecting thallus, adding acetic acid-sodium acetate buffer solution containing L-sodium glutamate, triton and pyridoxal phosphate as a conversion system, and performing conversion culture at 30 ℃ for 24-72 h to obtain GABA conversion solution;

the whole cell transformation method is characterized in that lactobacillus brevis is used as a GABA production strain, the mass fraction of the strain is inoculated to 18-22 g/L, acetic acid-sodium acetate buffer solution is used as a transformation system, and the GABA transformation solution is obtained after 24-72 h of transformation at 30 ℃;

the buffer solution is acetic acid-sodium acetate buffer solution added with 0.1 percent of triton, 0.1 percent of pyridoxal phosphate, 6 to 7 percent of sodium L-glutamate and pH value of 4.2 to 4.6;

the centrifugation condition is 4 ℃, 8000 revolutions and 15 min of centrifugation;

② removal of color from GABA conversion liquid

Heating the prepared GABA conversion solution in a boiling water bath for 10 min, centrifuging to obtain a supernatant, adjusting the pH to 5.00-5.20 by using a glacial acetic acid solution, adding activated carbon according to a solid-to-liquid ratio of 1:50-1:100 for decolorization, adsorbing at 30 ℃ for 5-15 min, and performing suction filtration to obtain colorless or yellowish filtrate which is the GABA decolorization conversion solution;

the centrifugation condition is 4 ℃, 8000 revolutions and 15 min of centrifugation;

the glacial acetic acid content in the glacial acetic acid solution is 99%;

the diameter of the micropores on the surface of the activated carbon is 9-20 nm;

the GABA decoloring condition is that activated carbon is added according to the solid-liquid ratio of 1:50-1:100, the pH of a decoloring solution is 5.00-5.20, the decoloring temperature is 30 ℃, and the decoloring time is 5-15 min;

the conversion solution turns colorless or yellowish after the GABA decoloration.

The method is adopted to decolor the GABA whole cell transformation liquid, the decoloration process of the GABA transformation liquid is simplified, the decoloration raw materials are easy to obtain and low in cost, the GABA loss rate in the GABA decoloration transformation liquid is 6-10%, the activated carbon used in the decoloration process can be recycled, and the loss rate of the activated carbon is 2-6%.

Compared with the prior art, the method for removing the color of the GABA conversion solution has the following remarkable characteristics:

(1) the invention adopts a single-factor and response surface experiment to carry out an optimization experiment;

(2) in the invention, when the GABA conversion liquid is decolorized, compared with processes of decolorizing and purifying gamma-aminobutyric acid in Wuqiaoyou, Huangjun, Gaoyike and Gaoyanghua lactobacillus brevis fermentation liquid, the technology of decolorizing and purifying gamma-aminobutyric acid [ J ] fermentation technology communication is discussed, 2015,44(03) 12-17.2 yellow jun, Meile Heng, Husheng, Maojiawei, Liushiwang, Lijunping, Shengqing, xujing and Wuhui, the flocculation and decolorization process research of the gamma-aminobutyric acid fermentation liquid [ J ] food industry technology, 2009,30(07) 257 and 259+ 269.3 high Aiqiong, high yield gamma-aminobutyric acid lactobacillus fermentation condition optimization and separation and purification process research [ D ] Zhejiang river university, 2013.4. high sensitivity, Chongjian, Ficus, Liu Meng, Liu Benzhou and Huangjian chestnut, yellow Jian whole cell catalytic production gamma-aminobutyric acid conversion liquid [ J ] color removal research [ Fujian ] technology, 17-23 percent in 2020(01), on the premise of ensuring the decoloring efficiency, the consumption of the activated carbon is small, the decoloring time is short, the decoloring cost is reduced, and meanwhile, the obtained GABA can be applied to the food industry.

(3) The loss rate of the active carbon is 2-6%, the active carbon can be recycled, and the energy is saved and the environment is protected;

(4) the GABA decoloring conversion solution obtained by the invention is colorless or yellowish, the loss rate of GABA in the GABA decoloring conversion solution is between 6 and 10 percent, and the loss rate of GABA is lower.

Example 1:

preparing GABA transformation liquid by whole cell transformation method

Taking lactobacillus brevis as GABA production strain, centrifuging cultured lactobacillus brevis for 48 h, collecting thallus, adding acetic acid-sodium acetate buffer solution containing L-sodium glutamate, triton and pyridoxal phosphate as a conversion system, and performing conversion culture at 30 ℃ for 24-72 h to obtain GABA conversion solution;

the whole cell transformation method is characterized in that lactobacillus brevis is used as a GABA production strain, the mass fraction of the strain is inoculated to 18-22 g/L, acetic acid-sodium acetate buffer solution is used as a transformation system, and the GABA transformation solution is obtained after 24-72 h of transformation at 30 ℃;

the buffer solution is acetic acid-sodium acetate buffer solution added with 0.1 percent of triton, 0.1 percent of pyridoxal phosphate, 6 to 7 percent of sodium L-glutamate and pH value of 4.2 to 4.6;

the centrifugation condition is 4 ℃, 8000 revolutions and 15 min of centrifugation;

② removal of color from GABA conversion liquid

Heating the prepared GABA conversion solution in a boiling water bath for 10 min, centrifuging to obtain a supernatant, adjusting the pH to 5.00-5.20 by using a glacial acetic acid solution, adding activated carbon according to a solid-to-liquid ratio of 1:50-1:100 for decolorization, adsorbing at 30 ℃ for 5-15 min, and performing suction filtration to obtain colorless or yellowish filtrate which is the GABA decolorization conversion solution;

the centrifugation condition is 4 ℃, 8000 revolutions and 15 min of centrifugation;

the glacial acetic acid content in the glacial acetic acid solution is 99%;

the diameter of the micropores on the surface of the activated carbon is 9-20 nm;

the GABA decoloring condition is that activated carbon is added according to the solid-liquid ratio of 1:50-1:100, the pH of a decoloring solution is 5.00-5.20, the decoloring temperature is 30 ℃, and the decoloring time is 5-15 min;

after the GABA is decolored, the conversion solution is converted into colorless or yellowish;

the GABA whole cell transformation liquid is decolorized by adopting the method, the loss rate of GABA in the GABA decolorization transformation liquid is 6.6%, and the loss rate of activated carbon is 2.7%.