Water-soluble Photopolymerization System And Its Appications On Immobilization Of Organophosphorus Hydrolase

Organophosphorus hydrolase(OPH)can efficiently hydrolyze organophosphorus compounds containing P-O,P-F,P-S and P-CN.However,industrial application of OPH is often hampered by short catalytic lifetime,difficulty of preservation,and non-recyclability.Combination of free OPH to an insoluble support to prepare a water-insoluble immobilized enzyme can overcome these limitations.In this thesis,polyethylene glycol diacrylates(PEGDAs)with different molecular weights(MWs)were synthesized for OPH immobilization from acryloyl chloride and polyethylene glycol,and the preparation conditions of PEGDAs were studied.PEGDAs were characterized by IR and 1H-NMR.PEGDA-Gels with different network structures were prepared by photo-curing under 365 nm UV light by using PEGDAs as pre-polymers and 2-Hydroxy-4'?(2-hydroxyethoxy)-2-methylpropiophenone(I-2959)as the photoinitiator.The Morphology of PEGDA-Gels were obtained by scanning electron microscopy(SEM)and the swelling properties were investigated by completely immersing the PEGDA-Gels into deionized water.The results showed that the PEGDA-Gels from photocuring of PEGDAs possessed porous structure,and PEGDA-Gels from high-MW PEGDA exhibited larger mesh size and better water absorption than that from low-MW PEGDA.OPH was immobilized in PEGDA-Gels by photocuring(PEGDA-Gel@OPH).In this method,Photopolymerization reaction conditions are mild and cause no serious damage to the OPH during immobilized preparation.The stability of PEGDA-Gel@OPH and free OPH were tested at various conditions,such as pH and temperature.Compared with free OPH,PEGDA-Gel@OPH was more stable at room temperature and resistant to high temperatures and pH.At repeated degradation of methyl parathion for 10 times,the activity of PEGDA-Gel@OPH was not remarkably lost.