Magnetically Agitated Nanoparticle-Based Batch Reactors for Biocatalysis with Immobilized Aspartate Ammonia-Lyase

Ali Obaid Imarah,Evelin Sánta-Bell,Diána Balogh-Weiser,László Poppe,Zsófia Molnár,Naran Bataa,Pál Csuka,Balázs Decsi

doi:10.3390/catal11040483

Abstract

In this study, we investigated the influence of different modes of magnetic mixing on effective enzyme activity of aspartate ammonia-lyase from Pseudomonas fluorescens immobilized onto epoxy-functionalized magnetic nanoparticles by covalent binding (AAL-MNP). The effective specific enzyme activity of AAL-MNPs in traditional shake vial method was compared to the specific activity of the MNP-based biocatalyst in two devices designed for magnetic agitation. The first device agitated the AAL-MNPs by moving two permanent magnets at two opposite sides of a vial in x-axis direction (being perpendicular to the y-axis of the vial); the second device unsettled the MNP biocatalyst by rotating the two permanent magnets around the y-axis of the vial. In a traditional shake vial, the substrate and biocatalyst move in the same direction with the same pattern. In magnetic agitation modes, the MNPs responded differently to the external magnetic field of two permanent magnets. In the axial agitation mode, MNPs formed a moving cloud inside the vial, whereas in the rotating agitation mode, they formed a ring. Especially, the rotating agitation of the MNPs generated small fluid flow inside the vial enabling the mixing of the reaction mixture, leading to enhanced effective activity of AAL-MNPs compared to shake vial agitation.

Highlights

Are of regular shakers, in a shake vial (SH), lyst fixed to the magnetic nanoparticles (MNPs) along with the liquidthere phase the reaction—containing the the biocatalyst fixed to the
Our study focused on the influence of different modes of magnetic agitation on effective enzyme activity of aspartate ammonia-lyase from Pseudomonas fluorescens immobilized on magnetic nanoparticles (AAL-MNP) in biotransformations of L-aspartic acid performed in batch mode
The two magnetic agitation modes applied two permanent magnets fixed at two opposite sides of a vial containing the AAL-MNPs in the reaction medium in two configurations

Summary

Introduction

Sustainable and environmentally conscious development requires the advancement and application of economical, efficient, and green processes to meet the needs of different industries and users. Among the solutions suitable for the production of various materials to satisfy these needs, efficient catalytic technologies come to the fore, within which the ever-evolving biocatalytic processes play an important role [1,2]. A bioreactor is the heart of any biochemical process in which a wide variety of useful biological products are processed using enzymes, microbial, or plant cell systems [3]. Magnetic mixing reactor (MMR) using paramagnetic internal elements within a reactor agitated by an external magnetic field is a well-known way of mixing. A unique way of implementation is when the internal paramagnetic element is powder-like. The basic principle of magnetic mixing was first described by the patents of Hershler in 1965 [4,5]

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