Isolation And Purification,physical And Chemical Properties Of ?-galactosidase From Flammulina Velutipes And Its Application

In this study,?-galactosidase in Flammulina velutipes was separated and purified,and its physical and chemical properties were studied.Using fresh F.velutipes fruiting body as material,an acidic?-galactosidase FVG was isolated and purified by anion exchange chromatography and gel filtration chromatography.The purification fold and the specific activity were 275.92 and 178.74 units/mg.The recovery rate is 4.3%.The molecular weight of this enzyme is about 63kDa,which is a single subunit structure and belongs to the GH 27 family.The optimum p H and temperature of the enzyme are 4 and 50.The enzyme was stablewithin an acidic p H range of 3-5 and in a narrow temperature range of 4-30.Pb²⁺,Hg²⁺,Fe³⁺,Al³⁺ and other metal ions,as well as melibiose,galactose,and SDS,have a stronger inhibitory effect on FVG activity,and the inhibition strength is related to the concentration.The chemical modifier NBS can obviously inhibit the activity of FVG,DIC and PMSF have a significant promotion effect on FVG activity,indicating that tryptophan,arginine,and serinase are essential groups of the enzyme's active center.FVG has a higher tolerance to acid protease and trypsin,and a relatively low tolerance to neutral protease.It has the strongest hydrolysis effect on p NPG,followed by stachyose,and extremely hydrolysis on other substrates is low or not.In this study,an ?-galactosidase FVG was isolated and purified from the fruiting body of F.velutipes for the first time,which increases the source of ?-galactosidase,and its physical and chemical properties provide reference value for the application of this enzyme in food and industry.In order to develop and utilize ?-galactosidase in F.velutipes,we use F.velutipes and soybean as the main raw materials,by adding the crude ?-galactosidase solution of F.velutipes to soybean milk.The single-factor and response surface methods were used to optimize the production process.The optimal production technology of F.velutipes soybean milk powder was: the ratio of the weight of soybeans to the volume of water is 1:4,the volume ratio of F.velutipes crude enzyme solution to soybean milk is 3:7,reaction time is 3h,reaction temperature is 40,monoglyceride added amount is 0.010g/mL,maltodextrin added amount is 0.20g/mL,spray drying inlet temperature is 177.The developed F.velutipes soybean milk has good color,smell and taste,which provides a certain theoretical basis for the utilization and intensive processing of ?-galactosidase in F.velutipes.