Pullulanase and production method thereof

Abstract

The invention relates to pullulanase and a production method thereof, and belongs to an amylolytic enzyme acted on an alpha-1,6-glucosidic bond. The pullulanase and the production method are characterized in that: a, zymologic characteristic is that the optimal pH is 3.8 to 4.4, the stable pH is 3.5 to 4.5, and the optimal action temperature is 50 to 65 DEG C; and b, Bacillus licheniformis is selected as an enzyme producing strain and derived from China Center of Industrial Culture Collection (CICC No.10185), and the pullulanase is prepared by a liquid state fermentation process in a mode of compositely feeding a backing material and a feed supplement and the method meets the following technological indexes that: (1) the enzymatic activity of the product is more than or equal to 1,100u / ml; (2) the fermentation period is 72 to 80 hours; and (3) the liquid enzyme recovery rate is more than or equal to 86.5 percent. The pullulanase product has the advantages of high heat resistance and acid resistance, high enzymatic activity, stable performance and low cost; the liquid biological fermentation production method has the advantages of high fermentation enzymatic activity, high extracting yield and low manufacturing cost; and the pullulanase and the production method are suitable for the fermentation industry using starch as a raw material and manufacturing of modified starch products, amylose starch and high-amylose starch.

Description

Technical field [0001] The present invention is a pullulanase and its production method. It belongs to starch hydrolyzing enzymes acting on α-1,6-glycosidic bonds. Background technique [0002] Starch is a product of photosynthesis of green plants. In plant starch, the content of amylopectin accounts for about 70%-95%, such as 74% in corn, 76% in potatoes, 75% in wheat, 81% in rice, and glutinous rice. Accounted for 100%. The relative molecular weight of amylopectin is very large, about 1 million to 6 million. In amylopectin, as in amylose, D-glucose units are also connected to form a straight chain by α-1,4-glycosidic bonds, but on this straight chain, they are formed by α-1,6-glycosidic bonds. Side chain, another branched side chain will appear on the side chain. Therefore, the structure is very complicated, forming a tree-like branch structure. Since amylopectin contains about 4% to 5% of α-1, 6-glycosidic bonds, and traditional amylase has weak hydrolysis ability of α-1,...

AI Technical Summary

Problems solved by technology

[0005] 1. Poor heat resistance, the optimum temperature is around 60°C, and the activity drops rapidly above 60°C;

[0006] 2. Poor acid resistance, unstable pH below 5.0;

[0007] 3. Low enzyme activity and high manufacturing cost;

[0008] 4. Expensive