Process for refining gulonic acid

Abstract

The invention discloses a process for refining gulonic acid. The process comprises the following steps of: performing ultrafiltration on fermentation liquor containing sodium gulonate; acidizing the fermentation liquor subjected to the ultrafiltration by using an ion exchange device, wherein the pH value of the fermentation liquor in the ion exchange device is below 2.0; performing nanofiltration preconcentration on the acidized fermentation liquor to obtain preconcentrated liquor; adsorbing the preconcentrated liquor by using active carbon or adsorbent resin; and performing triple effect evaporation on the adsorbed preconcentrated liquor to obtain concentrated liquor, and crystallizing the concentrated liquor to obtain a gulonic acid crystal. In a refining process route, the fermentation liquor is subjected to the ultrafiltration, ion exchange, the nanofiltration preconcentration to remove a large number of macromolecular impurities and soluble protein, and the preconcentrated liquor subjected to the nanofiltration preconcentration is adsorbed to remove impurities such as residual sugar, the soluble protein, pigments and the like further, so the quality of feed liquor before crystallization is optimized, the purity and yield of products are improved, and the discharge capacity of mother liquor is reduced.

Description

technical field [0001] The invention relates to a fermentation refining process, in particular to a refining process for producing the precursor of vitamin C, that is, gulong acid. Background technique [0002] The production of vitamin C by fermentation can be divided into fermentation (fermentation of microbial bacteria to prepare a fermentation broth containing sodium guronate), extraction (purification of the precursor of vitamin C-gulong acid from a fermentation broth containing sodium guronate) and transformation (conversion of cologne Acid is converted into vitamin C) in three steps. Separation of sodium guronate from waste mycelia and bacterial metabolites, conversion of sodium guronate in the fermentation broth into guronic acid, and successful separation of pure guronate are difficult problems in the refining process. In the entire cost control, the cost of the refining process is also a step that occupies a large proportion, so advanced refining technology is of ...

AI Technical Summary

Problems solved by technology

However, the composition of the remaining gulonic acid mother liquor after crystallization is very complicated. On the one hand, the remaining gulonic acid mother liquor after crystallization must contain fermentation residual impurities such as sorbose, protein, and nucleic acid in the fermentation broth before crystallization; In the process of evaporating and concentrating the fermentation broth and extracting gulonic acid, a large number of new impurities will inevitably be produced due to strong acid and overheating: for example, some gulonic acid molecules will be broken during the evaporation and concentration process to form formic acid, oxalic acid, and butene Diacids; part of sorbose will be oxidized and dehydrated to produce hydroxymethylfurfural, hydroxymethylfuroic acid, and valeric acid; some proteins and nucleic acids will be decomposed to produce polypeptides and nucleosides; newly formed small molecules will be repolymerized to form black and viscous polymer humic acid

Therefore, the residual sugar, protein, nucleic acid and other impurities existing before crystallization not only pollute the mother liquor of gulong acid itself, but also produce more complex components that are more difficult to remove during the crystallization process, which ultimately affects the crystallization quality and yield.

Therefore, using the above-mentioned methods to recycle the gulon acid mother liquor will become very complicated due to the existence of various impurities, and it is also difficult to improve the purity and chroma of the gulonic acid crystals, and the technical applicability is not strong

Images