Preparation And Application Of Molecularly Imprinted Adsorbent For Separating Bovine Serum Albumin From Dairy Wastewater

Bovine serum albumin(BSA)is a common animal protein and is the main component of bovine serum,in which bovine serum albumin is present in dairy wastewater.In order to recover BSA in dairy wastewater,this study used bovine serum albumin as a template to synthesize a molecularly imprinted polymer with high adsorption and selectivity for bovine serum albumin and applied the polymer to the separation and purification of bovine serum albumin in simulated dairy wastewater.Firstly,the molecularly imprinted polymer with specific selectivity to the template molecule is synthesized by the preparation method of precipitation polymerization.The best synthesis condition is obtained by experimenting and screening different kinds of functional monomers,cross-linkers and initiators.The conditions are as follows:under nitrogen,deionized water as solvent,methacrylic acid(MAA)as functional monomer;N,N'-Methylenebisacrylamide(MBA)as crosslinking agent;among them,BSA/MAA/MBA ratio is 1:6:3;potassium persulfate and sodium bisulfite system(K2S208-NaHS03)as initiator,and the ratio is 1:2;the eluent is sodium dodecyl sulfate(SDS)with acetic acid(HAC),and the ratio is 1%SDS(W/V)/10%HAC(V/V);the optimum temperature for the reaction is 40?.The physical properties of the polymer were analyzed and evaluated by Fourier transform infrared spectroscopy,specific surface area analysis,particle size analysis and scanning electron microscopy,thermogravimetric analysis and the optimal molecular imprinted polymer was selected by the adsorption amount and the specific adsorption degree.Secondly,the kinetic and adsorption isotherms and Scatchard analysis were performed on non-imprinted polymer(NIP)and molecularly imprinted polymer(MIP),respectively.The adsorption process of MIP to BSA is in accordance with quasi-secondary adsorption kinetics and Langmuir adsorption thermodynamic model.In the specific selection experiment,lysozyme was used as the interfering substance,and the molecularly imprinted polymer showed obvious specific adsorption,in which had good adsorption to bovine serum albumin and the separation factor was 3.09.In contrast,the non-imprinted polymer had no significant specificity with the separation factor of 1.01.The best MIP obtained in this study was used to separate BSA from simulated dairy wastewater.In the 30 ml simulated dairy wastewater with a bovine serum albumin concentration of 1 mg/ml,when the MIP was 1.2 g,the recovery rate of bovine serum albumin tended to be balanced,and the optimal recovery rate was 70.2%.In this process,the equilibrium time for adsorption and elution was 70 min,and the recovery was approximately 71%.The optimum MIP was measured for repeatability.After repeated elution and adsorption for 5 times,the recovery rate was reduced by about 10%.Specific selection experiments were carried out in actual milk with good separation effect.It indicated the feasibility of applying the optimal MIP synthesized to separate BSA from dairy wastewater.