α‑Amylase@Ferria: Magnetic Nanocomposites with Enhanced Thermal Stability for Starch Hydrolysis

• Published in: Journal of agricultural and food chemistry 2018-08, Vol.66 (30), p.8054-8060
• Main Authors: Astafyeva, Bazhena V, Shapovalova, Olga E, Drozdov, Andrey S, Vinogradov, Vladimir V
• Format: Article
• Language: English
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.8b01298

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.