Co-production process for xylobiose and xylose

Abstract

The invention discloses a co-production process for xylobiose and xylose. With the process, high-quality crystallized xylobiose is obtained, and the raw material--xylose for production of xylitol is obtained at the same time. The process comprises the following concrete steps: subjecting a corncob to alkali treatment and then to filtering so as to obtain a dissolved-out solution and separating and purifying xylan by using an ethanol precipitation method; degrading purified xylan with xylanase in an enzymatic membrane reactor to obtain a xylobiose solution and subjecting the xylobiose solution to concentration, decoloring and purifying so as to obtain purified xylobiose liquor; and subjecting the purified xylobiose liquor to purification with a three-component simulated moving bed so as to obtain a xylose component, a xylobiose component and a miscellaneous saccharide component. According to the invention, an enzymatic membrane reactor method is used for enzymatic hydrolysis of xylan, reaction and separation are carried out at the same time, yield of xylobiose is high, cost is low, and the enzymatic membrane reactor method is a key technology of the invention.

Description

technical field [0001] The invention relates to a production method for co-producing xylose from xylobiose. Background technique [0002] Xylose is an aldose with five carbon atoms. As a food additive, it is mainly used as a sweetener for diabetics. In industry, it is an auxiliary agent in printing, dyeing and tanning. With the wide application of xylitol as a therapeutic agent for diabetic patients, and the development of xylitol as a sweetener for anti-cavity chewing gum, candy, beverages, etc., xylose, as a raw material for xylitol production, is also widely used by people. focus on. [0003] Xylobiose is the main active ingredient of xylooligosaccharides, and also the qualitative and quantitative components of xylooligosaccharides. It has unique physiological functions and good process performance. Its sweetness is about 40% of that of sucrose, and its sweetness is refreshing and soft. It is a hotspot in the research of functional oligosaccharides, which is used in man...

AI Technical Summary

Problems solved by technology

[0005] In the existing xylobiose production technology, the enzymatic hydrolysis of xylan adopts free enzyme method or ordinary immobilized enzyme method. Patent CN1303091C adopts free enzyme method for hydrolysis. The cost is high, and the steam required to inactivate the enzyme will also increase a lot of cost; the patent CN1916171A uses a metal chelating epoxy carrier to immobilize xylanase. This immobilization method not only affects the enzyme activity, but also needs to use a membrane to intercept wood Polysaccharides, high cost

[0006] In the xylobiose solution obtained by enzymatic hydrolysis of xylan, although the macromolecular xylan has been trapped by the membrane, there are still some xylooligosaccharides and monosaccharides left in the xylobiose solution. proximity, resulting in difficult and costly purification of xylobiose

Patent CN1847254A adopts polyacrylamide gel column chromatography to separate components of xylooligosaccharides. Because the gel is expensive and difficult to regenerate, it is only used in laboratory research at present, and it is difficult to use it on the scale of a single component of xylooligosaccharides Chemical production; Patent CN101632877A uses activated carbon chromatography to separate components in xylooligosaccharides. This method uses ethanol as the eluent, which has high cost. Moreover, the service life of activated carbon is short, and the workload of loading and unloading carbon is large , and take up a large amount of production time, a large amount of waste carbon also produces a lot of production waste, and the separation performance of activated carbon is poor, and the product purity obtained is low; the simulated moving bed purification adopted by the inventor's patent CN101830936B is two-component separation, Separation of xylooligosaccharides to obtain xylobiose components and miscellaneous sugar components, although the content of xylobiose components is relatively high, but the purification yield is low, and the two cannot be well balanced

[0007] Regarding the crystallization method of xylobiose, the patent whose publication number is CN101475609A adopts the method for adding inorganic salt and organic solvent to carry out crystallization. Solvent, high cost; the inventor’s patent CN101830936B adopts the method of vacuum freeze-drying to prepare solid xylobiose, because freeze-drying only plays the effect of removing moisture, but does not achieve the effect of purification, so the product obtained is also low in purity, and Freeze-drying consumes a lot of energy; the patent with the publication number CN1916171A proposes vacuum concentration at 55°C to a supersaturated state, adding seed crystals, and crystallizing at room temperature to obtain xylobiose crystals

Although the xylobiose purity obtained by this method reaches more than 99%, the crystallization yield is low, only 34%

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