Method for preparing threonine crystal by threonine fermentation liquid

Abstract

The invention relates to a method for preparing threonine crystal by threonine fermentation liquid, comprising the steps of: sterilizing the threonine fermentation liquid, and the carrying out plate-type or tube-type film ultrafiltration, concentration, azeotropic crystallization and other steps to prepare the threonine crystal; and the prepared threonine crystal has the purity of 98.5%, the threonine film ultrafiltration yield of more than 96%, and the azeotropic crystallization yield of more than 95%. The preparation method is an environment-friendly new production technique which has high efficiency, low energy consumption, low cost, simple method and easy popularization.

Description

technical field [0001] The invention belongs to the technical field of amino acid separation and purification production, and in particular relates to a method for preparing threonine crystals from threonine fermentation broth. Background technique [0002] Threonine is an essential amino acid for humans and animals, which can restore human fatigue and promote growth and development. However, the human body and animals cannot synthesize threonine by themselves, and must obtain it from external sources such as food. Therefore, threonine is widely used as a food fortifier, feed additive, pharmaceutical preparation, health care product, etc., with broad application prospects and strong market demand. [0003] The production methods of threonine include protein hydrolysis, synthesis and direct fermentation. Direct fermentation is currently the main method for producing threonine, which has the advantages of low raw material cost and easy large-scale production. The traditiona...

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Problems solved by technology

[0004] The patent application CN200610014324.4 of Tianjin University of Science and Technology discloses a method for separating and extracting L-threonine from the fermentation broth. The method uses a metal tubular microfiltration membrane to filter the fermentation broth. Compared with the traditional method, the quality of the filtrate is improved. However, the removal rate of pigment and protein by the microfiltration membrane needs to be improved, and activated carbon decolorization is required to further improve the quality of the feed solution, and the crystallization method still adopts the isoelectric point method of adjusting the pH value of the solution for one crystallization and the ethanol precipitation method for recrystallization twice. method, the crystallization mother liquor still needs to be applied mechanically, therefore, the technology of this method is long, the yield is low, and the discharge of crystallization mother liquor is large

[0005] The patent application CN200710097998.1 of Changchun Dacheng Industrial Group Co., Ltd. discloses a method for extracting threonine from threonine fermentation broth. This method uses inorganic ceramic membranes to filter the fermentation broth, which can improve the quality of the filtrate, but requires activated carbon for further decolorization; The crystallization method adopts the method of cooling from 70°C to 5°C. The crystallization mother liquor still uses water as the solvent, which has a small dissolving ability for impurities such as pigments. A large amount of threonine is also dissolved in the mother liquor, and the crystallization yield is low. It is necessary to concentrate the crystallization mother liquor for two Secondary crystallization or reuse of mother liquor, there are disadvantages such as low yield and high energy consumption