초록
<P><B>Abstract</B></P> <P>In this work, the structural thermostabilization of the characterized nanomagnetic cross-linked enzyme aggregates of naringinase have been considered. Comparisons have been made between free and immobilized enzyme by the determination of temperature-dependent half-lives (t<SUB>1/2</SUB>), energy barriers of thermal inactivation (E<SUB>a(in)</SUB>) process, and thermodynamic parameters (ΔH*, ΔG*, and ΔS*) in a storage thermostability approach. Samples of NM-NGase-CLEAs were treated at different temperatures in the range of 40–80 °C for 90 min. The K<SUB>m</SUB> values of immobilized enzyme was reduced about 10.7 folds compared to the free one. The catalytic efficiency (k<SUB>cat</SUB>/K<SUB>m</SUB>) was raised about 10.5 folds after immobilization. Enzyme half-life (t<SUB>1/2</SUB>) of NM-NGase-CLEAs increased from 18.7 to 52.9 min (about 3 folds) at 80 °C. The thermodynamics study indicated that E<SUB>a(in)</SUB> of the free enzyme increased from 38.51 to 49.14 (KJ·mol<SUP>−1</SUP>) and ΔH* increased from 35.57 to 46.20 (KJ·mol<SUP>−1</SUP>) after immobilization, which indicates an increase in the thermostability of this multimeric enzyme after nanomagnetic CLEAs fabrication. The NM-CLEAs of naringinase preserved 73% of its original activity after 10 cycles, which implies strong operational stability. Thus, the developed method for nanomagnetic CLEAs preparation has provided an efficient and simple approach for the productive and reusable nanobiocatalyst together with ease in enzyme handling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Naringinase nanobiocatalyst was fabricated by NM-CLEAs method. </LI> <LI> Energy barriers of thermal inactivation (E<SUB>a(in)</SUB>) and ΔH* of NM-NGase-CLEAs were raised. </LI> <LI> Catalytic efficiency (k<SUB>cat</SUB>/Km) of the enzyme was increased after immobilization. </LI> <LI> The K<SUB>m</SUB> values of NM-NGase-CLEAs were reduced while, enzyme half-life increased. </LI> <LI> Thermostability of naringinase was enhanced after nano immobilization by CLEAs method. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>