Physical and chemical immobilization of choline oxidase onto different porous solid supports: Adsorption studies

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Passos, MLC (Author) Other; Ribeiro, DSM (Author) Other; Joao L M Santos (Author) FFUP; Lucia L M F S Saraiva (Author) FFUP

Journal

Title: Enzyme and Microbial Technology

Vol. 90

Pages: 76-82

ISSN: 0141-0229

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 3 Citations

Other information

Authenticus ID: P-00K-FT1

DOI: 10.1016/j.enzmictec.2016.05.004

Abstract (EN): This work carries out for the first time the comparison between the physical and chemical immobilization of choline oxidase onto aminated silica-based porous supports. The influence on the immobilization efficiency of concentration, pH, temperature and contact time between the support and choline oxidase, was evaluated. The immobilization efficiency was estimated taking into consideration the choline oxidase activity, which was assessed by using cadmium telluride (CdTe) quantum dots (QDs), obtained by hydrothermal synthesis, as photoluminescent probes. Hydrogen peroxide produced by enzyme activity was capable of quenching CdTe QDs photoluminescence. The magnitude of the PL quenching process was directly related with the enzyme activity. By comparing the chemical process with the physical adsorption, it was observed that the latter provided the highest choline oxidase immobilization. The equilibrium data were analyzed using Langmuir and Freundlich isotherms and kinetic data were fitted to the pseudo-first-order and pseudo-second order models. Thermodynamic parameters, such as Gibbs free energy and entropy were also calculated. These results will certainly contribute to the development of new sensing schemes for choline, taking into account the growing demand for its quantification in biological samples.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7