Study on technology for extracting nattokinase by ultrafiltration
Objective:Studyed the impact of membrane flux on utrafiltration system pressure,ultrafiltration temperature and pH,determined the optimum conditions of nattokinase separation.Methods:the raw materials was prepared from crude nattokinase liquid,by ultrafiltration and chromatography determined the specific activity,purification multiples and recovery rate.Results:The optimized conditions were as following:reaction pressure 0.25 MPa,liquid temperature 37 ℃,liquid pH 7,the specific activity 9610.46 IU/mg,the purification multiple 2.36 and the recovery rate 92.3%,the purified enzyme was demonstrated by SDS-PAGE to be a homogeneous protein,molecular mass was about 28000 u.Conclusion:It is feasible to separate and purify nattokinase by using ultrafiltration technology,and it can elevate activity and the recovery rate.