Method for producing L-arabinose and D-xylose

Abstract

The invention relates to a method for producing L-arabinose and D-xylose, which can simultaneously produce ethanol or D-ribose or citric acid as a byproduct. The method utilizes a hydrolyzate of agricultural waste, a xylose mother liquor and/or a production waste liquor containing pentose as the raw materials and comprises the following steps: (1) pretreating the raw materials; (b) carrying out the chromatographic resolution to separate the raw materials into an arabinose-stage liquor and a xylose-stage liquor; (c1) removing fermentation inhibitors which are impurities and unwanted bacteria, which have an inhibiting effect on the fermentation; (c2) fermenting to remove unwanted saccharides at least comprising glucose and galactose; (d) and finally, respectively carrying out the post treatment on the arabinose-stage liquor and the xylose-stage liquor to obtain the L-arabinose and the D-xylose. Steps (c1) and (c2) are arranged before the chromatographic resolution in step (b) or after step (b). The method has the advantages of low production cost and high efficiency, and is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the production technology of L-arabinose and D-xylose, especially the production of L-arabinose and D-xylose products using hemicellulose hydrolyzate, xylose mother liquor and production waste liquid containing five-carbon sugar as raw materials 1. A method for simultaneously by-producing fermentation products such as ethanol or D-ribose or citric acid. technical background [0002] L-arabinose belongs to the five-carbon aldose, and exists in the form of arabinan, arabinoxylan, arabinose galactose and hemifiber similar to higher plants. L-arabinose is a sweetener without calories, and can also be used as a pharmaceutical intermediate, for the preparation of bacterial culture media in the biochemical field, and for the synthesis of spices, etc. Xylose products such as xylose and xylitol are more and more popular as food sweeteners. Many health care functions of xylose and xylitol have been confirmed by scientific research, suc...

AI Technical Summary

Problems solved by technology

The limitations and deficiencies of this patent are: 1) only corncobs can be used to produce arabinose and xylitol, and the raw material source is single; Molecular substances and metal ions and other substances are removed, so that the fermentation cannot be carried out smoothly; 3) This patent does not have a step of removing glucose and galactose before the chromatographic separation of arabinose and xylitol, which leads to the failure of chromatographic separation of arabinose and xylitol. Purification; 4) Candida tropicalis is used for the fermentation of the feed liquid, and arabinose generates arabinitol while removing xylose and glucose, thereby consuming a large amount of arabinose or even exhausting it so that arabinose products cannot be obtained; 5) the patent The technology can only produce xylitol, but cannot directly produce xylose, and its application range is greatly limited

This patented technology also has the following two defects: (1) xylose hydrolyzate or xylose mother liquor are directly added to Saccharomyces cerevisiae without pretreatment so that fermentation is not easy to carry out. Toxic substances, such as: pigment substances with benzene rings, polymer compounds, heavy metal ions, chlorides, etc.

These poisons will accelerate the aging and death of yeast, so that the fermentation time is long and incomplete

(2) Glucose is only removed, and galactose is also contained in the sugar solution. The existence of galactose affects the crystallization of xylose and arabinose, thereby reducing the crystallization yield or even failing to crystallize

All miscellaneous sugars including xylose and xylan in this patent are fermented and removed by yeast, which brings about several problems: First, xylan cannot be fermented by yeast and must be hydrolyzed into monosaccharides before fermentation ;In addition, the main component in the hydrolyzate is xylose, if you want to ferment to remove most xylose, you must use a strain that can utilize five-carbon sugar, which will inevitably lead to the loss of arabinose fermentation

And because the xylose content is high, if it is removed as an impurity, on the one hand, a large amount of xylose will be wasted, and a great economic price will be paid. On the other hand, xylose will not be completely converted into carbon dioxide and water after fermentation, but will generate other metabolic Intermediate products, such as: glycerol, pyruvic acid, glyceraldehyde, xylulose, etc.

These impurities are not easily removed by crystallization, resulting in insufficient purity of the arabinose product

[0007] In summary, in the prior art, there is no production method with low cost and high efficiency that can realize large-scale industrial production of high-purity L-arabinose and xylose / xylitol

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