Studies on improved techniques for immobilizing and stabilizing penicillin amidase associated with E. coli cells

Area of Science:

• Biocatalysis and Enzyme Technology
• Biotechnology and Bioengineering

Background:

• Conventional methods for immobilizing whole cells containing penicillin amidase face challenges like substrate/product permeation and protein leaching.
• These limitations can lead to reduced specific activity compared to immobilized enzyme systems.

Purpose of the Study:

• To develop and optimize a whole cell immobilization method for E. coli expressing penicillin amidase.
• To overcome limitations of conventional methods and improve catalyst performance.

Main Methods:

• Optimization of whole cell immobilization process parameters for E. coli with penicillin amidase.
• Key parameters optimized include pH, cell concentration, glutaraldehyde concentration, and bovine serum albumin concentration.
• Catalyst characterization for mechanical strength, protein leachability, and enzyme activity retention.

Main Results:

• Optimal conditions identified: pH 4.25, 3.75% cell concentration, 1.5% glutaraldehyde, and 2 mg/ml bovine serum albumin.
• The resulting granular catalyst exhibited good mechanical strength and low protein leachability.
• High retention of penicillin amidase activity was observed in the immobilized whole cells.

Conclusions:

• The optimized whole cell immobilization technique provides a robust and efficient method for developing biocatalysts.
• This approach effectively addresses issues of protein leaching and mechanical instability in immobilized enzyme systems.
• The developed granular catalyst demonstrates significant potential for industrial applications requiring penicillin amidase activity.