Co-Aggregation of Penicillin G Acylase and Polyionic Polymers:  An Easy Methodology To Prepare Enzyme Biocatalysts Stable in Organic Media

• Published in: Biomacromolecules Vol. 5; no. 3; pp. 852 - 857
• Main Authors: Wilson, Lorena, Illanes, Andrés, Abián, Olga, Pessela, Benevides C. C, Fernández-Lafuente, Roberto, Guisán, José M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-05-2004
• Subjects: Applied sciences; Biological and medical sciences; Biotechnology; Catalysis; Enzyme Stability; Enzymes - chemistry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Hydrolysis; Immobilization of enzymes and other molecules; Immobilization techniques; Ions; Methods. Procedures. Technologies; Natural polymers; Penicillin Amidase - chemistry; Physicochemistry of polymers; Polymers - chemistry; Starch and polysaccharides; Coating material; Enzyme; Molecular cluster; Dextran derivatives; Experimental study; Solvent resistance; Thermal stability; Penicillin amidase; Organic sulfate; Hydrolases; Oside polymer; Immobilized enzyme; Polyethylene imine
• DOI: 10.1021/bm0343895
• EISSN: 1526-4602
• ISSN: 1525-7797

A novel type of biocatalyst that combines the good properties of cross-linked enzyme aggregates (CLEAs) and hydrophilic microenvironments has been developed. Dextran sulfate- and polyethyleneimine-coated CLEAs of penicillin acylase (CLEA-GDP) were prepared by adding the polymers of different sizes before the precipitation stage of the enzyme. This study presents the development and optimization of a protocol to produce such a biocatalyst using penicillin acylase as a model. Experiments show that CLEA-GDPs have a highly increased stability in organic media. The average half-life of the preparations was much higher than standard CLEA without a microenvironment (CLEA-G), (e.g., more than 25-fold) in the presence of dioxane. However, their thermal stability was not increased, which leads to the conclusion that the stability of CLEA-GDPs in organic media is due to the hydrophilic microenvironment that surrounds the protein enzyme more than to a conformational stiffening effect. This is further supported by solvation experiments that show a preferential hydration of CLEA when polymers are used to coat the enzyme. CLEA-GDPs are clearly better than other biocatalysts in terms of solvent stability.