Hybrid materials parameters influencing the enzyme activity of immobilized cells

Abstract

Hybrid materials, synthesized by the sol-gel method, were used as matrices for immobilization of bacterial cells, producers of the enzyme nitrilase. Different methods were employed for structure investigations of the synthesized hybrids: Fourier transform infrared spectroscopy (FT-IR), BET and atomic force microscopy (AFM). The influence of the structure of these materials on their properties was followed. The obtained hybrid materials were successfully applied for immobilization of live bacterial cells since cell vitality was kept and enzyme systems preserved their functions in the immobilized systems. The influence of different parameters during the cell immobilization procedure was evaluated for optimization of the immobilization process and enhancement of the activity of the studied enzyme. Most favorable effect on Bacillus sp. cells had the matrix with 5 wt. % sepharose and the enzyme activity obtained was 0.45 U ml(-1) when the process was carried out at 60 degrees C. Increased specific surface area of the matrix was another factor that led to enhanced nitrilase activity.