The Optimization Of Hydrolysis Lactose To D-galactose By Enzyme

D-galactose is the component of agarose, vegetable gum, glue, raffinose and lactose. It’s a monosaccharide that prepared by the hydrolysis of lactose. D-galactose can promote the intellectual development of infants. D-galactose is the precursor of D-tagatose. D-tagatose is an excellent sweetener which can also improve the intestinal flora and prevent the hyperglycemia. D-galactose can synthesize a variety of anti-cancer drugs. So, the value and market of D-galactose will be increasingly large. However, preparing the D-galactose generate a lot of byproducts with the traditional acid hydrolysis method and while lactose hydrolysis is not complete. In this paper, we use the enzymatic method to hydrolyze the lactose, and make the depth research on reaction conditions. It has a great influence on reducing the cost of galactose industrialization.1.Enzymatic Preparation D- galactose Optimization.In this paper we use the single factor experiment to optimize the reaction conditions including the temperature, p H, enzyme amount, substrate concentration and the a mount of pyridoxal phosphate etc. Then we use the orthogonal to detect the influence of metal ions on the reaction. The experimental results are optimal reaction conditions for the reaction temperature is 65 ℃, the amount of enzyme solution added 3.3 m L / kg, the initial reaction p H was 4.5, the initial substrate concentration of lactose content of 20%. PLP added choice has no effect on the reaction. Choose 6 kinds of metal ions on the reaction was inhibited, and the restraining force size ranking of Cu2 +> Fe2 +> K +> Mn2 +> Zn2 +> Mg2 +.2.Isolation and purification of D- galactose.After hydrolysis of lactose by the best hydrolysis process, we use the yeast to remove the D- glucose. Then the fermentation broth was purified by centrifuged, bleaching, filtration,recrystallization.3.D- galactose production.We put 5 tons lactose into the industrial production equipment and production Dgalactose with the best hydrolysis process. The production of D- galactose in compliance withquality requirements, and the product purity is 98.0%, the total yield of the product was38.7%.