Chinese Journal of Chemical Engineering, Vol.27, No.1, 191-199, 2019
Immobilization of organophosphorus hydrolase enzyme by covalent attachment on modified cellulose microfibers using different chemical activation strategies: Characterization and stability studies
The plant cellulose powder was activated by two different methods using 1,4-butanediol diglycidyl ether (BTDE) and 1,1'-Carbonyldiimidazole (CDI) as the chemical coupling agents. Organophosphorus hydrolase (OPH) from Flavobacterium ATCC 27551 was immobilized on any of activated support through covalent bonding. The optimal conditions of affecting parameters on enzyme immobilization in both methods were found, and it was demonstrated that the highest activity yields of immobilized OPH onto epoxy and CDI treated cellulose were 68.32% and 73.51%, respectively. The surface treatment of cellulose via covalent coupling with BIDE and CDI agents was proved by FTIR analysis. The kinetic constants of the free and immobilized enzymes were determined, and it was showed that both immobilization techniques moderately increased the K-m value of the free OPH. The improvements in storage and thermal stability were investigated and depicted that the half-life of immobilized OPH over the surface of epoxy modified cellulose had a better growth compared to the free and immobilized enzymes onto CDI treated support. Also, the pH stability of the immobilized preparations was enhanced relative to the free counterpart and revealed that all enzyme samples would have the same optimum pH value for stability at 9.0. Additionally, the immobilized OPH onto epoxy and CDI activated cellulose retained about 59% and 68% of their initial activity after ten turns of batch operation, respectively. The results demonstrated the high performance of OPH enzyme in immobilized state onto an inexpensive support with the potential of industrial applications. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.