Method for separating alpha-ketoglutaric acid from conversion solution

Abstract

The invention discloses a method for separating alpha-ketoglutaric acid from a conversion solution, which comprises the following steps: sequentially carrying out ceramic filtration, ultrafiltration and reverse osmosis on the conversion solution to obtain an alpha-ketoglutaric acid concentrated solution; reacting the obtained concentrated solution with calcium superchloride, and filtering to obtain alpha-ketoglutarate; adding the alpha-ketoglutarate and ethanol into a reaction kettle, slowly and dropwisely adding sulfuric acid, stopping adding the acid when the pH value of the ethanol solution is 1.3-1.5, stirring to react to generate a calcium sulfate precipitate, filtering, and collecting the filtrate which is a ketoglutaric acid ethanol solution; eluting the residual alpha-ketoglutaric acid from the calcium sulfate with ethanol, and collecting the eluting solution; and mixing the filtrate and eluting solution, and heating and concentrating under reduced pressure to precipitate the alpha-ketoglutaric acid crystal. The membrane filtration technique is adopted to avoid abundant water evaporation; and thus, the method has the advantages of energy saving, high production yield, favorable crystal form, light color of the crystal grain, and stable product quality, and can easily implement industrialized large-scale production.

Description

technical field [0001] The invention relates to the technical field of preparation of alpha-ketoglutaric acid. Background technique [0002] α-ketoglutaric acid is an important organic acid, which plays an important role in the metabolism of microbial cells. It is one of the important intermediate metabolites of the trihydroxy acid cycle and participates in the metabolism of amino acids, sugars, proteins and fats, etc. It is an important physiological process and is an important precursor substance for the synthesis of various amino acids and proteins. Therefore, it is widely used in the food, medicine, chemical and cosmetic industries, and the market demand is huge. At present, the production and preparation methods of α-ketoglutaric acid mainly include chemical synthesis, microbial fermentation synthesis and enzyme-catalyzed conversion. Among them, the chemical synthesis method has long chemical synthesis routes, low yields, and the use of toxic chemical reagents and othe...

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Problems solved by technology

[0003] However, the disadvantage of the fermentation method is that there are many fermentation by-products, the subsequent separation and purification work is difficult, the yield is low, and the purification cost is too high

Although the enzymatic conversion method has fewer by-products than the fermentation method, it also has the problems of difficulty in subsequent separation and purification, low yield and high purification cost

[0004] At present, the separation and purification methods of α-ketoglutaric acid in the conversion liquid are mainly as follows: firstly, the conversion liquid is pretreated, and the conversion liquid is added with aluminum sulfate, polyacrylamide, chitosan or other inorganic aluminum salts, iron Salt, polymer flocculant, etc., and then filtered; the filtered conversion solution is then absorbed and eluted by cationic resin and anionic resin, and the eluent is mostly sulfuric acid or ammonia water, which introduces other impurities. It affects subsequent purification, resulting in poor product quality and low yield, and the crystallized product is yellow-white or yellow powder; and the traditional process often crystallizes the unqualified crude product first, and then performs secondary crystallization to make the product meet the qualified standard, and the cost of secondary crystallization is high. The process is complicated, and because the solvent is water, the evaporation temperature is high, the energy waste is serious, and the material cannot be recycled multiple times

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