D-Galactose Production Based On The Asymmetric Degradation Fermentation

D-galactose is one of aldehyde sugars;belong to the common kind of hexose.Clinical studies indicated that D-galactose associated with some diseases,such as in tumor diagnosis and treatment.At the same time,D-galactose can promote infant intelligence development,D-galactose induced aging animal models are widely used at home and abroad.In addition,D-galactose can also be used as raw materials to product D-tagatose which can inhibit hyperglycemia,improve intestinal flora,avoid dental caries,and so on.to product oxidation of hydroxyl galactose which has anti-cancer,anti-inflammatory,anti-TB virus physiological functions and synthesis L-Ribose.Therefore,D-galactose was widely used in scientific research and production in recent years,the amount increased significantly and with a potential market value.This paper introduces a kind of D-galactose production,perfects the process of D-galactose production and gets the qualified D-galactose products through the research of lactose hydrolysis,strains fermentation and post-extraction.In order to effectively hydrolyze the lactose,single factor and orthogonal array design methods were used to optimize process parameters including lactose concentration,material-acid ration,hydrolysis time,hydrolysis temperature under the laboratory-existing conditions.The optimal hydrolysis conditions were determined as follows:lactose concentration,11%;material-acid ration,100:16(g/g);hydrolysis time,6h;hydrolysis temperature,127?.The residual rate of lactose was 2.84%under the optimal hydrolysis conditions.In order to obtain strains for glucose degradation,the purpose of strain HC-27 which can not degrade D-galactose was isolated from grapery soil after enrichment,screening and rescreening.The ratio of liquid medium and the growth conditions of the strain were studied.The optimal culture medium and the culture conditions of strain HC-27 were established as follows:glucose 0.5%,peptone 1.0%,yeast extract 1.0%,potassium dihydrogen phosphate 0.1%,magnesium sulfate 0.05%;culture time 26 h,temperature 30? pH 6.0.shaker rotate speed 100 r/min.Through the optimal hydrolysis conditions,vaccination strain fermentation and a series of processes such as vacuum filtration,ion exchange,vacuum concentration and convection drying,D-galactose finished products were obtained.The results showed that 26.42g D-galactose crystal could be gained by hydrolyzing 110g lactose,the yield is about 24%and the purity was 97.36%.