Process for extracting lactic acid from fermentation liquid

Abstract

This invention relates to a technical proposal of producing lactic acid by deep layer fermentation, that is the proposal of extracting lactic acid from fermentation liquor. The features are that desugarization and decoloration are done by using granular active carbon and H-103 resin column. Two times consumption of heat is adopted, that is the temperature reduces from 300C to 15, then from 150C to 40C, and calcium lactate is extracted through once crystallization. The loss of lactic acid is much reduced and the technology continuance is realized by this invention. The extraction rate and purity are raised, the percent crystallinity can reach 80%, purity 97.2%, the extraction rate of lactic acid exceeds 70% and stability of finished product lactic acid is good.

Description

technical field [0001] The invention relates to a process for producing lactic acid by submerged fermentation, in particular to a process for extracting lactic acid from fermentation broth. Background technique [0002] Lactic acid is one of the three recognized organic acids in the world, widely used in food, medicine, chemical industry and other fields. In recent years, with the development of research on the polymerization of L-lactic acid into biodegradable polymer materials, the production and application research of L-lactic acid has set off a new climax at home and abroad, and the market demand for L-lactic acid with high optical purity is very high. look good. [0003] At present, the production of L-lactic acid with high optical purity is mainly based on microbial fermentation, and the fermentation strains include Lactobacillus and Rhizopus oryzae. There are many large-scale enterprises in our country that use starch as raw material to produce lactic acid through ...

AI Technical Summary

Problems solved by technology

[0006] The process has the advantages of easy control and simple equipment requirements, but it has many unit operations, high labor intensity, serious environmental pollution, low product extraction rate and low purity.

The reasons for the low extraction rate and low purity of lactic acid are as follows: main impurities such as sugars, proteins and pigments in the fermentation broth significantly affect the crystallization rate and purity of calcium lactate; the multiple decolorization of activated carbon used makes the loss rate of calcium lactate and lactic acid As high as 30%, and resulting in continuous process and low degree of automation; insufficient sugar removal in the process, resulting in residual sugar or other reducing substances in the finished lactic acid affecting the quality of the product; in addition, the calcium lactate crystallization process requires harsh conditions and is not easy to control

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