Enzyme immobilization in mesoporous silica
Doktorsavhandling, 2013

Enzymes are highly effective and versatile biological catalysts, with a high chemo-, stereo- and regioselectivity while operating under mild conditions, such as physiological temperature and pH and atmospheric pressure. Therefore, enzymes are a sustainable alternative to conventional catalysts in organic synthesis processes. They are also used in detergent formulations, in biosensors for analytical and diagnostic purposes, and in biofuel cells. However, the use of enzymes in their native form often results in high costs, low operational stability and difficulties in recovery and reuse. By immobilization of enzymes to a solid support these limitations can be minimized. Mesoporous silica materials are a promising support for enzyme immobilization, offering a large surface area, a narrow pore size distribution and a high stability. Immobilization of enzymes in mesoporous silica has become a popular research topic, but despite the many techniques available, there is still a need for controlled strategies in order to adapt the support to the specific enzyme. It is crucial to better understand how the enzyme is affected by the microenvironment inside the pores and to gain more knowledge about the immobilization process. A major part of this work has been focused on finding suitable mesoporous silica particles customized for an optimal performance of each individual type of enzyme investigated. Enzymes of different character were immobilized in mesoporous silica particles with varied pore size, particle size and particle morphology through physical adsorption. The influence of these parameters on the loading capacity, catalytic activity and reusability of the immobilized enzymes was evaluated. A method to study the microenvironment inside mesoporous silica particles by covalently attaching a pH-probe (SNARF1) to proteins was developed. The results indicate that the immobilized proteins experience an environment inside the pores which is closer to neutral compared to the bulk solution. This approach can be used to characterize the pore environment without perturbing the properties of the material. The immobilization process has been studied directly with quartz crystal microbalance with dissipation monitoring (QCM-D) by attaching silica particles to the sensor. We have demonstrated that QCM-D is a simple and robust measuring technique for real time study of enzyme immobilization into mesoporous silica particles and that it is a useful complement to conventional indirect measuring techniques. With QCM-D we were also able to follow the co-immobilization of glucose oxidase (GOD) and horseradish peroxidase (HRP), which was done by immobilization of GOD in mesoporous silica particles followed by adsorption of HRP covalently linked to a polycationic dendronized polymer. A cascade reaction was confirmed with enzymatic activity analysis.

particle morphology

Mesoporous silica

quartz crystal microbalance with dissipation monitoring

immobilization

enzyme

pH probe

biocatalysis

pore size

Kollektorn
Opponent: Galen Stucky

Författare

Hanna Gustafsson

SuMo Biomaterials

Chalmers, Kemi- och bioteknik, Teknisk ytkemi

A method to measure pH inside mesoporous particles using protein-bound SNARF1 fluorescent probe

Microporous and Mesoporous Materials,; Vol. 165(2013)p. 240-246

Artikel i vetenskaplig tidskrift

Immobilization of lipase from Mucor miehei and Rhizopus oryzae into mesoporous silica - The effect of varied particle size and morphology

Colloids and Surfaces B: Biointerfaces,; Vol. 100(2012)p. 22-30

Artikel i vetenskaplig tidskrift

QCM-D as a method for monitoring enzyme immobilization in mesoporous silica particles

Microporous and Mesoporous Materials,; Vol. 176(2013)p. 71-77

Artikel i vetenskaplig tidskrift

Immobilization of feruloyl esterases in mesoporous materials leads to improved transesterification yield

Journal of Molecular Catalysis - B Enzymatic,; Vol. 72(2011)p. 57-64

Artikel i vetenskaplig tidskrift

A comparison of lipase and trypsin encapsulated in mesoporous materials with varying pore sizes and pH conditions

Colloids and Surfaces B: Biointerfaces,; Vol. 87(2011)p. 464-471

Artikel i vetenskaplig tidskrift

Ämneskategorier

Fysikalisk kemi

Nanoteknik

Miljöbioteknik

Styrkeområden

Materialvetenskap

ISBN

978-91-7385-882-3

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie

Kollektorn

Opponent: Galen Stucky

Mer information

Skapat

2017-10-07