Preparing method of xylitol

A technology of xylitol and xylose, applied in the field of preparation of xylitol, can solve problems such as large amount of coenzyme, and achieve the effects of saving production cost and reducing cost

Inactive Publication Date: 2018-06-22
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] Purpose of the invention: In order to solve the problem that the amount of coenzyme used in the existing enzymatic preparation of xylitol

Method used

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  • Preparing method of xylitol
  • Preparing method of xylitol
  • Preparing method of xylitol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Induction and expression of embodiment 1 xylose reductase

[0033]1. The xylose reductase gene sequence (GenBank: AB002105.2) of Candida tropicalis IFO 0618 was found in the NCBI database, and the xylose reductase gene sequence was optimized according to the codon preference of Escherichia coli. After optimization The nucleotide sequence is shown in SEQ ID NO: 1, and the nucleotide sequence was synthesized by Jinweizhi Company.

[0034] Analysis of rare codons: The rare codons were mainly analyzed by the software E.coli Codon Usage Analysis 2.0 to obtain the codons whose relative frequency of use in Escherichia coli was lower than the threshold (10‰).

[0035] Optimize rare codons: optimize the codons whose usage frequency is lower than the threshold according to the usage frequency of different codons in E. coli.

[0036] The optimized xylose reductase gene was subcloned between the EcoRI and HindIII restriction sites of plasmid pET-28a to form a recombinant plasmid. ...

Embodiment 2

[0064] The enzyme-catalyzed reaction is added according to the following system:

[0065]

[0066] After enzymolysis, heat to inactivate the enzyme, and then filter through the water-based membrane to detect the product components in the liquid phase. The liquid phase conditions: (1) The chromatography column is Aminex HPX-87C, the mobile phase is ultrapure water, and the flow rate is 0.6mL / min , the column temperature was 80°C, and detected with a refractometer RID. The results showed that xylose and glucose had been completely converted. (2) The chromatographic column is Aminex HPX-87H, and the mobile phase is 5mMH 2 SO 4 , flow rate 0.4mL / min, column temperature 45°C, detect xylitol content with a refractometer RID. The conversion rate of xylitol in the product is 98%, and the concentration can reach 146.23g / L; the conversion rate of gluconic acid is 95%, and the concentration can reach 185.05g / L, and a very small amount of sorbitol and xylonic acid are also generated...

Embodiment 3

[0071] The method is the same as in Example 2, adding and carrying out the enzyme-catalyzed reaction according to the following system:

[0072]

[0073]

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Abstract

The invention discloses a preparing method of xylitol. Xylose, glucose, xylose reductase, glucose dehydrogenase, coenzyme, CaCO3 and water form a biological catalysis system, so that xylose is catalyzed to be subjected to a reduction reaction to generate xylitol. Specifically, xylose reductase and NADPH serve as a catalysis system to catalyze xylose to be subjected to the reduction reaction to generate xylitol; glucose dehydrogenase serves as a regenerated catalyst of NADPH, glucose is catalyzed to be subjected to an oxidation reaction to generate gluconic acid, and NADP+ is catalyzed to be subjected to a reduction reaction to generate NADPH. Dual enzymes are adopted to produce xylitol, and after the reaction is conducted for 24 h, xylose and glucose are completely consumed; in products, the converting rate of xylitol is 98%, the concentration of xylitol can reach 146.23 g/L, the converting rate of gluconic acid is 95%, and the concentration of gluconic acid can reach 185.05 g/L.

Description

technical field [0001] The invention relates to sugar alcohols, in particular to a preparation method of xylitol. Background technique [0002] Xylitol is a five-carbon sugar alcohol and an intermediate product of xylose metabolism. It is widely found in fruits, vegetables and some plants in nature, but its content is relatively low, so it is not suitable for large-scale extraction. Since the 1860s, xylitol has been used as a food additive and sweetener. In recent years, its application in food ingredients has continued to expand, mainly due to its physicochemical properties: high chemical and biological stability Xylitol can be used as a food preservative to prolong the shelf life of food products; at the same time, it does not undergo Maillard reaction with amino acids, and will not reduce the nutritional value of protein; xylitol’s sweetness is comparable to sucrose, but its calorific value is far away Lower than sucrose, it is one of the foods that modern people can mai...

Claims

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Application Information

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IPC IPC(8): C12P7/18
CPCC12P7/18Y02P20/584
Inventor 应汉杰常子月柳东李楠王振宇杨正娇吴昕洋
Owner NANJING UNIV OF TECH
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