Formulation of organic and inorganic hydrogel matrices for immobilization of β‐glucosidase in microfluidic platform

Abstract

The aim of this study was to formulate silica and alginate hydrogels for immobilization of β-glucosidase. For this purpose, enzyme kinetics in hydrogels were determined, activity of immobilized enzymes was compared with that of free enzyme, and structures of silica and alginate hydrogels were characterized in terms of surface area and pore size. The addition of polyethylene oxide improved the mechanical strength of the silica gels and 68% of the initial activity of the enzyme was preserved after immobilizing into tetraethyl orthosilicate-polyethylene oxide matrix where the relative activity in alginate beads was 87%. The immobilized β-glucosidase was loaded into glass-silicon-glass microreactors and catalysis of 4-nitrophenyl β-d-glucopyranoside was carried out at various retention times (5, 10, and 15 min) to compare the performance of silica and alginate hydrogels as immobilization matrices. The results indicated that alginate hydrogels exhibited slightly better properties than silica, which can be utilized for biocatalysis in microfluidic platforms.

Biodegradation of Crystalline Cellulose Nanofibers by Means of Enzyme Immobilized-Alginate Beads and Microparticles

“…With the freeze-drying, a shrinkage of the particles occurred and a less spherical shape with a wrinkled and porous surface was distinguished by SEM. The addition of the enzyme cellulase did not appreciably change the shape and appearance of the corresponding alginate particles, indicating that enzyme encapsulation does not significantly change bead morphology [ 67 ].…”

“…With the freeze-drying, a shrinkage of the particles occurred and a less spherical shape with a wrinkled and porous surface was distinguished by SEM. The addition of the enzyme cellulase did not appreciably change the shape and appearance of the corresponding alginate particles, indicating that enzyme encapsulation does not significantly change bead morphology [67]. Table 1 shows the mean particle size of the obtained hydrogel and dried beads processed after using different formulations with varied parameters like the concentrations of alginate and CaCl2 coagulation bath, addition or not of NaCl, and hardening time (HT).…”

The Promises and the Challenges of Biotransformations in Microflow

“…Further introduction of nanomaterials including biomimetic structures in microreactors, together with the genetic introduction of tags in bacterial cells and enzymes, offers the possibility for more specific immobilization and spatial organization of biocatalysts at specific sites, especially using DNA nanotechnology as a programmable tool for engineering multienzyme catalysis . Microflow format was found beneficial also for packed‐bed reactors (Figures f and e) with biocatalysts immobilized in porous beads, on streptavidin‐coated superparamagnetic microbeads, in electrospun nanomats, or in various hydrogels, recently also prepared as alginate‐silica hybrids, which have the advantages of homogenous structure, better stability, and nontoxicity, and are injectable . Miniaturized packed‐bed reactors enabled not only very high enzyme loads, but also very good accessibility and operational stability of biocatalysts due to diminished fluid flow anomalies such as back mixing and dead zones, and very low‐pressure drop …”

Synthesis of alginate‐silica hybrid hydrogel for biocatalytic conversion by β‐glucosidase in microreactor

“…2). Recently, Kazan et al [43] prepared TEOS-PEO, EGMS-PEO, and alginate aerogels as a support material for β-glucosidase. 2C, D, G, and H).…”

“…Some studies show that organic and inorganic based monoliths for enzyme immobilization could not reach higher surface area compared to organic-inorganic hybrid monoliths. Recently, Kazan et al [43] prepared TEOS-PEO, EGMS-PEO, and alginate aerogels as a support material for β-glucosidase. Surface area of these aerogels were 10, 9, and 384 m 2 /g, respectively.…”