Improvement of DERA activity and stability in the synthesis of statin precursors by immobilization on magnetic nanoparticles

Abstract

Deoxyribose-phosphate aldolase (DERA), an enzyme applied in the synthesis of precursors for statin production, was immobilized on magnetic nanoparticles (MNPs). The silanized MNPs were functionalized/activated by several agents with different concentrations: APTMS/APTES–glutaraldehyde, APTMS/APTES–benzoquinone, APTMS/APTES–succinic anhydride and GPTMS. APTES–succinic anhydride (15%) provided the best result, and modification of the immobilization conditions was performed. The highest obtained retained activity and stability of 179% and 60%, respectively, were at pH 6.5 and 20 °C. A kinetic model for the immobilized enzyme reaction was developed and validated in a batch reactor. In reusability tests, immobilized DERA showed better stability than the free enzyme and maintained 70% enzyme activity after three cycles, while an almost complete loss of activity for the free enzyme after the second cycle was noticed.