Chitosan flakes for papain immobilization: improving the stability and reusability of the enzyme

Abstract

Background. The global papain market is growing because of its diverse applications in the food, chemical, and textile sectors, although the enzyme's solubility in free form causes reactor losses. This study aims to immobilize papain on chitosan flakes, preserving its catalytic activity for repeated reuse. Materials and methods. The immobilization process employed citric acid and ethylenediaminetetraacetic acid (EDTA) in a physical adsorption approach. Results. Papain loading of 0.2 to 0.4 g per gram of chitosan flakes yielded optimal digesting results. When 0.4 g of immobilized papain per gram of chitosan flakes was added, a 2% gelatin solution digested 96.9%. Conclusion. Notably, papain immobilization on chitosan flakes is achieved without the need for additional chemicals, relying on enzyme concentration and relative enzyme-to-flake weight. This work demonstrates chitosan's potential as an effective medium for physically preserving papain, showcasing its applicability in enzyme immobilization endeavors.