Immobilized enzyme

About: Immobilized enzyme is a research topic. Over the lifetime, 15282 publications have been published within this topic receiving 401860 citations.

Enabling multienzyme biocatalysis using nanoporous materials.

Abstract: Multistep reactions catalyzed by a covalently immobilized enzyme-cofactor-enzyme system were achieved. Lactate dehydrogenase (LDH), glucose dehydrogenase (GDH), and cofactor NADH were incorporated into two porous silica glass supports. One of the glass supports had pores of 30 nm in diameter, while the other was of 100-nm pore size. Effective shuttling of the covalently bound NADH between LDH and GDH was achieved, such that regeneration cycles of NADH/NAD(+) were observed. The glass of 30-nm pore size afforded enzyme activities that were about twice those observed for the glass of 100-nm pore size, indicating the former provided better enzyme-cofactor integration. The effect of the size of spacers was also examined. The use of longer spacers increased the reaction rates by approximately 18 times as compared to those achieved with glutaraldehyde linkage. It appeared that the concave configuration of the nanopores played an important role in enabling the multistep reactions. The same multienzyme system immobilized on nonporous polystyrene particles of 500-nm diameter was only approximately 2% active as the glass-supported system. It is believed that the nanoporous structure of the glass supports enhances the molecular interactions among the immobilized enzymes and cofactor, thus improving the catalytic efficiency of the system.

Electrochemical biosensor for the detection of formaldehyde based on enzyme immobilization in mesoporous silica materials

Abstract: Mesoporous silica materials have a potential application for enzyme immobilization, which increases the stability of enzymes. We report the development of a novel detection method based on biosensors comprising an immobilized enzyme in mesoporous silica materials (i.e., FSM8.0 or P123-M), an electrochemical mediator (i.e., quinone), and an electrochemical cell, using the enzyme formaldehyde dehydrogenase. These biosensors exhibit a rapid response and high sensitivity, and they can detect 1.2 μM of formaldehyde in an aqueous solution (corresponding to sub-ppb atmospheric concentration of formaldehyde). Furthermore, the sensors exhibit high selectivity, reusability, and a remarkable storage stability (stable over 80 days), indicating that formaldehyde dehydrogenase retains its highly ordered structure in these mesoporous silica materials. These results indicate that mesoporous silica materials can provide favorable methods for enzyme immobilization on the electrode and they are useful for developing high-performance electrochemical biosensors.

Functionalized Multi‐Wall Carbon Nanotubes for Lipase Immobilization

Abstract: We examine the immobilization of lipase B from Candida antarctica on functionalized multi-wall carbon nanotubes (MWCNTs) through physical adsorption. MWCNTs functionalized with carboxyl-, amine- and ester- terminal groups on their surface are used as immobilization carriers. Dispersion of the nanotubes and the immobilization procedure take place in aqueous and low-water media. High enzyme loadings are attained, up to 25% of the weight of the carbon nanotubes. These novel biomaterials are characterized though FT-IR and Raman spectroscopy. The MWCNT–lipase bioconjugates exhibit high catalytic activity and increased storage and operational stability. The biomaterials retain more than 55% of their initial activity after 6 months at 4 °C, while they retain approximately 25% of their initial activity after 30 d of incubation in hexane at 60 °C. The catalytic behaviour of the immobilized enzyme depends on the terminal group of the carbon nanotubes, the concentration of the enzyme and the immobilization method employed.