Improved process for clean production of xylose

Abstract

The invention discloses an improved process for clean production of xylose. The process comprises the steps that forestry and agricultural residues are subjected to pretreatment of raw material, enzymolysis, solid-liquid separation, concentration, pre-decoloration and chromatographic separation and purification, and then refining and crystallization of xylose are achieved and purification and crystallization of arabinose are achieved. The improved process for clean production of xylose has the advantages that the steam explosion temperature is relatively low, and a continuous production is achieved through a steam explosion technology; xylan in the raw materials are transformed to xylose and the transformation rate reaches 95% or above; moreover, impurities in a xylose solution are reduced, the steam explosion time is greatly shortened, water consumption is reduced, chromatographic separation resin is protected, the service life of the resin is prolonged, steam is effectively saved and the steam explosion cost is reduced.

Description

technical field [0001] The invention relates to the technical field of xylose production, in particular to an improved clean xylose production process. Background technique [0002] The traditional xylose production process is an acid hydrolysis process, specifically decolorizing, desalting, concentrating, etc. The step of refining is crystallization and centrifugation to obtain crystalline xylose after purification. In this process, the content of sulfate ions is high, and the desalination process consumes a lot of acid and alkali and water, which is the main source of sewage in xylose production. At the same time, sulfuric acid can inhibit the activity of anaerobic bacteria in activated sludge. [0003] The patent No. 201410701716.4 "A Process for Clean Production of Xylose" mentioned a production process similar to enzymatic preparation of xylose. The present invention made the following improvements on the basis of this patent: 1. Continuous steam explosion 2. Reduce t...

AI Technical Summary

Problems solved by technology

[0004] Patent No. 200610040383.0 describes a similar method in the patent "Enzymatic Preparation of Xylose", but there are the following deficiencies: 1. The pretreatment mentioned in this method refers to alkali extraction or steam explosion, and does not specify the specific process parameters , different steam explosion equipment and conditions result in different sugar liquid components that directly affect the amount of enzyme added, so it belongs to insufficient disclosure; The sugar solution after enzymatic hydrolysis contains a large amount of xylan and other unlabeled miscellaneous sugars, and the purity of xylose is less than 50%. It is well known that the crystallization purity of xylose needs to reach more than 75%.

3. Using ethanol to precipitate impurities, the cost of ethanol is high, the operating environment is poor, the effect of removing impurities is not obvious, and industrial production is not cost-effective

[0005] Patent No. 200510045325.2 mentions a similar process in the patent "A Method for Enzymatic Production of Xylose", but there are the following deficiencies: 1. The said pretreatment of the method refers to high-pressure cooking or steam explosion, and high-pressure Cooking conditions, however, the plant fiber hemicellulose after high-pressure cooking is not stripped out, which is not conducive to the infiltration of enzymes, and the efficiency is low; the patent does not mention the specific process parameters and equipment types of steam explosion, which is insufficient disclosure; 2. The enzyme mentioned refers to exo-xylanase, and technically speaking, a single exo-xylanase is inefficient and needs to work with other enzymes; 3. The conversion of xylan to xylose mentioned in the patent The conversion rate reaches more than 80%, which is not advanced. The conversion rate of the traditional sulfuric acid hydrolysis method is more than 85%.

[0006] The patent No. 201110162361.2 "A Clean and Efficient Production Process for the Preparation of Xylose and L-arabinose" mentions a similar process, but there are the following deficiencies: 1. The enzyme used for enzymolysis is Aspergillus niger crude enzyme solution, the composition The complex efficiency is low, the refining cost is high, and the specificity is not high; 2. The high-temperature cooking mentioned in this method provides high-pressure cooking conditions, but the reaction time is long, and there are many side reactions. The hemicellulose in the plant fiber after high-temperature cooking Without steam explosion separation, it is not conducive to the infiltration of enzymes or microorganisms, and the efficiency of enzymatic hydrolysis is low