Immobilization of Mucor miehei esterase on core-shell magnetic beads via adsorption and covalent binding: Application in esters synthesis

Abstract

In this work, poly(hydroxyethyl methacrylate/glycidylmethacrylate), p(HPMA-GMA), magnetic beads were prepared via suspension polymerization, and grafted with poly(methacrylic acid), p(MMAc) via redox polymerization. Esterase from M. miehei was immobilized onto core-shell magnetic beads with two different methods (i.e., adsorption and covalent binding). For adsorption, the effects of pH and initial esterase concentration on the immobilization efficiency via adsorption have been studied. The maximum adsorption capacity of the magnetic beads for esterase was found to be 27.6 mg/g magnetic beads at pH 7.0. The covalent immobilization of esterase via carbodiimide coupling on mp(HEMA-GMA)-gp(MAAc) beads was found to be the more effective than the direct immobilization of the enzyme on the mp(HEMA-GMA) beads. The covalently immobilized esterase on the mp(HEMA-GMA)-g-p(MAAc) beads exhibited higher activity compared to the adsorbed esterase on the same magnetic beads. Tributyrin hydrolysis properties of the free and both immobilized esterase preparations were determined under different experimental conditions. The operational, thermal and storage stabilities of the immobilized esterase preparations were increased compared with the free esterase. Finally, esterification reactions have been performed to produce citronellyl-esters (namely: acetate, butyrate and propionate) in n-hexane medium using covalently immobilized esterase. The immobilized esterase was effectively reused in successive batch runs in n-hexane medium for citronellyl-butyrate synthesis, and only 23 % activity was lost after 6 cycles.

Immobilization of Thermoalkalophilic Esterase Onto Magnetic-Cornstarch Nanoparticle

“…The conformational change of esterase might be constricted by the immobilization matrix without temporarily affecting under denaturant conditions such as high temperatures. Similar to the present study results, three reports have shown that esterase immobilization on different MNP supports including core-shell magnetic beads [39], silane functionalized superparamagnetic nanoparticles (SNPs) [35] and Fe 3 O 4 ~ cellulose nanocomposite [36] improved thermal stability relative to their free esterases. Only one study has reported that the esterase immobilization process on MNPs did not change the enzyme thermostability [37].…”

“…Most of the esterase immobilization works using MNPs did not alter the optimum pH points compared to the free esterases as in the present study [35][36][37]. Only one study on Mucor miehei esterase immobilization using core-shell magnetic beads enhanced the optimal working pH as much as one unit, relative to the free esterase [39].…”

“…esterase using Fe 3 O 4 ~ cellulose nano-composite optimally worked at 30 o C and 35 o C, respectively [36]. Also, a free Mucor miehei esterase and its immobilized form on core-shell magnetic beads through adsorption and covalent binding showed an optimum temperature at 40 o C and 50 o C, respectively [39]. Similar to the present study, one report has shown that Pseudomonas putida IFO12996 esterase immobilization by MNPs exhibited a similar optimal working temperature compared to its free form [37].…”

“…Beside this, a recombinant esterase from Pseudomonas putida IFO12996 was covalently bound to MNPs through glutaraldehyde [37] and hexa-arginine-tagged esterase was immobilized on gold-coated magnetic nanoparticles [38]. Another esterase from Mucor miehei was immobilized on core-shell magnetic beads through adsorption and covalent binding for the synthesis of esters [39].…”

Thermoalkalophilic recombinant esterase entrapment in chitosan/calcium/alginate‐blended beads and its characterization

“…25,26 Among these, Mucor miehei esterase was immobilized on core-shell magnetic beads by adsorption and covalent binding for ester synthesis. 27 Another esterase BioH was immobilized on a hydrophilicmodified solid support through oriented adsorption. 28 In addition, the esterase BioH from Escherichia coli was immobilized onto hydrophilic-modified magnetic nanosupport via oriented covalent immobilization.…”