Topic
Immobilized enzyme
About: Immobilized enzyme is a research topic. Over the lifetime, 15282 publications have been published within this topic receiving 401860 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: Surface-active cellulose films for covalent attachment of bioactive moieties were achieved by codissolution of cellulose with polyamidoamine (PAMAM) dendrimers in an ionic liquid followed by regeneration of the composite as a film.
92 citations
TL;DR: A glucose amperometric biosensor based on glucose oxidase immobilized on an overoxidized polypyrrole (PPyox) platinum modified electrode, by glutaraldehyde co-crosslinking with bovine serum albumine, is described, showing an apparent Michaelis-Menten constant and excellent interferent rejection of electrosynthesized non-conducting polymers.
92 citations
TL;DR: The experiments indicated that laccase bound via glutaraldehyde to MCFs modified using 2-aminoethyl-3-aminopropyltrimethoxysilane remains very active, and in the best biocatalyst activity was about 42,700 U mL −1 carrier, and hence significantly higher than ever reported before.
92 citations
TL;DR: Graphite electrodes fabricated by screen-printing have been used as amperometric detectors in biosensors based on NAD+-dependent dehydrogenases, tyrosinase, or genetically modified acetylcholinesterases, detecting D-lactic acid and acetaldehyde in wine and phenols in air.
Abstract: Graphite electrodes fabricated by screen-printing have been used as amperometric detectors in biosensors based on NAD(+)-dependent dehydrogenases, tyrosinase, or genetically modified acetylcholinesterases. The mono-enzyme sensors have been optimized as disposable or reusable devices for detection of a variety of substrates important in the food industry ( D-lactic acid, L-lactic acid, acetaldehyde) or in environmental pollution control (phenols and dithiocarbamate, carbamate and organophosphorus pesticides). The sensors were prepared in four configurations differing in enzyme confinement, enzyme immobilization and location of the immobilization agent in the biosensor assembly. Tests on real samples have been performed with the biosensors; D-lactic acid and acetaldehyde have been detected in wine and phenols in air.
92 citations
TL;DR: The proposed protocol permitted the reuse of the most stable enzyme after inactivation of the least stable one, and is compatible with any immobilization protocol of the first enzyme that does not involve ion exchange as only reason for enzyme immobilization.
Abstract: This paper shows the coimmobilization of β-galactosidase from Aspergillus oryzae (β-gal) and lipase B from Candida antarctica (CALB). The combi-biocatalyst was designed in a way that permits an optimal immobilization of CALB on octyl-agarose (OC) and the reuse of this enzyme after β-gal (an enzyme with lower stability and altogether not very stabilized by multipoint covalent attachment) inactivation, both of them serious problems in enzyme co-immobilization. With this aim, OC-CALB was coated with polyethylenimine (PEI) (this treatment did not affect the enzyme activity and even improved enzyme stability, mainly in organic medium). Then, β-gal was immobilized by ion exchange on the PEI coated support. We found that PEI can become weakly adsorbed on an OC support, but the adsorption of PEI to CALB was quite strong. The immobilized β-gal can be desorbed by incubation in 300 mM NaCl. Fresh β-gal could be adsorbed afterwards, and this could be repeated for several cycles, but the amount of PEI showed a small decrease that made reincubation of the OC-CALB–PEI composite in PEI preferable in order to retain the amount of polymer. CALB activity remained unaltered under all these treatments. The combi-catalyst was submitted to inactivation at 60 °C and pH 7, conditions where β-gal was rapidly inactivated while CALB maintained its activity unaltered. All β-gal activity could be removed by incubation in 300 mM NaCl, however, SDS analysis showed that part of the enzyme β-gal molecules remained immobilized on the OC-CALC–PEI composite, as the inactivated enzyme may become more strongly adsorbed on the ion exchanger. Full release of the β-gal after inactivation was achieved using 1 M NaCl and 40 °C, conditions where CALB remained fully stable. This way, the proposed protocol permitted the reuse of the most stable enzyme after inactivation of the least stable one. It is compatible with any immobilization protocol of the first enzyme that does not involve ion exchange as only reason for enzyme immobilization.
92 citations