α-Amylase@ferria: magnetic nanocomposites with enhanced thermal stability for starch hydrolysis

Authors: Bazhena V. Astafyeva, Shapovalova O.E., Drozdov A. S., Vinogradov V.V.

Abstract

The present study is devoted to the development of a new class recyclable magnetic catalytic nanocomposites for starch hydrolysis. α-Amylase was entrapped within a magnetite-derived xerogel matrix in a course of a room-temperature sol–gel transition, leading to enzyme immobilization within the pores of a rigid magnetic matrix. For hybrid organo-inorganic composites with enzyme mass fractions less than 10 wt %, no enzyme leaching was observed. At 80 °C, the amylase@ferria composite demonstrates catalytic activity on the level of 10 units/mg and the starch hydrolysis rate comparable to free enzyme, while at 90 °C, the activity of amylase@ferria is at least twice higher than that of free amylase as a result of higher thermal stability of the composite. Entrapped amylase showed excellent stability and lost only 9% of its activity after 21 days of storage in a buffer solution, while free enzyme was totally inactivated after 17 days. The material can be used as either a magnetically separable reusable catalyst or a catalytic ceramic coating with at least 10 cycles of use.

DOI: 10.1021/acs.jafc.8b01298

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https://pubs.acs.org/doi/abs/10.1021/acs.jafc.8b01298