279108 Encapsulation of Laccase in Chitosan Micro-Carriers by Two-Fluid and Three-Fluid Nozzle

Thursday, November 1, 2012: 1:45 PM
Oakmont (Omni )
Ondrej Kaspar, Laboratory of Chemical Robotics, Institute of Chemical Technology, Prague, Prague, Czech Republic and Frantisek Stepanek, Laboratory of Chemical Robotics, Institute of Chemical Technology, Prague, Czech Republic

Encapsulation of laccase in chitosan micro-carriers by two-fluid and three-fluid nozzle

Ondřej Kašpar, František Štěpánek*

Department of Chemical Engineering, Institute of Chemical Technology Prague,

Technická 5, 166 28 Prague 6, Czech Republic

*Corresponding author. E-mail: Frantisek.Stepanek@vscht.cz; Tel.: +420 220 443 236

Chitosan is a biocompatible and biodegradable polymer suitable for the encapsulation of both small molecules and biomolecules. The simultaneous encapsulation of a precursor (substrate) and immobilization of catalyst (enzyme) in a core-shell chitosan particle makes it possible to deliver active molecules with a short half-life by forming them in-situ from stable precursors. This is desirable e.g. in the case of biocidal molecules or sensorially active substances.

The first objective of our study is to investigate the effect of composition (in particular, the TPP/chitosan ratio) and cross-linking method (ex-situ vs. in-situ) on the properties of chitosan microspheres formed by spray drying. The particle size distribution, particle morphology, zeta potential and swelling behaviour have been systematically investigated. A novel cross-linking method, based on in-situ contact of TPP and chitosan solutions directly at the nozzle orifice (3-fluid nozzle), has been developed and compared with a more conventional approach of spray-drying a pre-mixed TPP/chitosan colloid solution using a 2-fluid nozzle. The second objective is encapsulation of active substance (enzyme - laccase) and study of the influence of experiment set-up (inlet temperature, TPP/chitosan ratio, type of nozzle and cross-linking method) on enzymatic activity.

It will be shown that by a suitable combination of process and formulation parameters, cross-linked chitosan particles with a narrow size distribution and defined swelling properties and stability in aqueous media can be formed. Moreover, the immobilized enzyme (laccase) is shown to keep its activity even within the chitosan matrix after spray drying and rehydration, which makes it a suitable system for in-situ delivery of actives.


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