Engineering strain for generating allulose, construction method and application thereof

Abstract

The invention discloses a construction method of an engineering strain for generating allulose and an application thereof. The construction method comprises the following steps: increasing content ofintracellular fructose 6-phosphoric acid by reducing enzymatic activity of fructose 6-phosphokinase and glucose 6-phosphate dehydrogenase in corynebacterium glutamicum and enhancing enzymatic activityof glucokinase and glucose 6-phophate isomerase by regulating glucose intracellular metabolism; constructing a synthetic route of allulose composed of 6-aloxone phosphate 3-epimerase and 6-aloxone phosphate phosphorylase; constructing a metabolic pathway of fructose composed of fructose transmittase and fructokinase; constructing a metabolic pathway of glycerinum composed of glycerol transmittase, glycerol dehydrogenase and dihydroxyacetone kinase, thereby acquiring a corynebacterium glutamicum recombinant strain. The strain is capable of metabolizing glycerinum, glucose, fructose or saccharose for synthesizing allulose. Compared with the present reported method for compounding allulose through bioconversion of fructose, the construction method provided by the invention has the advantagesof high conversion rate, low production cost, and the like, and is suitable for large-scale production of allulose.

Description

technical field [0001] The invention belongs to the field of biotechnology, and in particular relates to an engineering bacterium for producing allulose, a preparation method of the engineering bacterium and its application in fermenting and producing allulose. Background technique [0002] Rare sugar is a type of monosaccharide and its derivatives that exist in nature but are very low in content (defined by the International Rare Sugar Society ISRS in 2002). In recent years, D-psicose, as an epimer of fructose, has attracted widespread attention in the fields of diet, health care, and medicine. The sweetness of D-psicose is 70% of that of sucrose, but its energy value is only 0.007kcal / g, and the energy absorption efficiency is only 0.3% of sucrose, it is a very ideal low-calorie sweetener, which can be used as a sucrose substitute in the food field; D-psicose has been proved to have hypoglycemic effect, It can also inhibit the activity of liver fat synthase intestinal α-...

AI Technical Summary

Problems solved by technology

[0003] At present, the production of psicose is mainly through chemical synthesis and biotransformation. Chemical synthesis requires multiple protection and deprotection steps, and the production cost is high and the yield is low.

The biotransformation method uses fructose as a raw material, and D-psicose 3-epimerase catalyzes the synthesis of D-psicose. This method has a high catalytic synthesis efficiency and is currently the main method for synthesizing psicose. However, the conversion rate of this method is low, and the highest conversion rate can only reach 32% at present. It is necessary to add simulated fluidized bed equipment to realize the recycling of fructose, which makes the product difficult to separate and increases the production cost of allulose. It is urgent to develop a low-cost, A new method for the synthesis of allulose with low pollution and high yield