Heat-resisting alkali-resisting and salt stable inulase exonuclease, and coding gene and application thereof

Abstract

The invention discloses an amino acid sequence and a nucleotide sequence of a heat-resisting alkali-resisting and salt stable inulase exonuclease, and construction and application of an inulase exonuclease recombinant expression vector. Results of enzymatic property research show that the optimum reaction conditions of the inulase exonuclease are as below: pH 7.0, 50 DEG C and 10% NaCl. The enzyme can catalyze the hydrolysis of inulase, levan, sucrose, raffinose, kestose, nystose and Kestopentaose. In a catalysis process using inulase as a substrate, only generation of fructose is detected rather than oligosaccharide or other carbohydrates. The inulase exonuclease provided by the invention can be applied to the field of food industry and biological energy source as a novel biocatalyst for fructose production.

Description

technical field [0001] The invention belongs to the field of biotechnology, and specifically relates to the amino acid sequence and nucleotide sequence of a heat-resistant, alkali-resistant and salt-stable exo-inulinase, the construction and application of the exo-inulinase recombinant expression vector. Background technique [0002] Inulin, also known as inulin, got its name because it was first isolated from the Compositae plant. In nature, 11 families including Asteraceae, Gentianaceae, and Tangerineaceae in dicotyledonous plants, as well as Liliaceae and Poaceae in monocotyledonous plants, all contain inulin. Inulin is abundant in plants such as Jerusalem artichoke, chicory, dandelion, burdock and dahlia, which are widely grown in our country. Inulin is a polyfructose formed by the dehydration polymerization of D-fructofuranose through β-2,1-glucosidic bonds. The reducing end of inulin is connected to a molecule of glucose residues by α-(1,2)-glycosidic bonds, forming ...

AI Technical Summary

Problems solved by technology

[0004] The main difficulties encountered in the research and application of inulinase: 1. The high cost of producing enzyme leads to high application cost

It is mainly manifested in the low enzyme production of inulinase-producing strains, which increases the application cost and restricts the application of fructooligosaccharides in the food industry, feed industry and bioenergy fields

Two, the most suitable enzyme reaction pH of inulinase used in industrial production is acidic environment (pH5.5-6.5), under neutral pH or alkaline pH environmental conditions, the activity of the enzyme and the stability of the enzyme are greatly improved. reduce

This limits the application of inulinase in alkaline environment to some extent

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