Enzyme-Polymer Conjugates to Enhance Enzyme Shelf Life in a Liquid Detergent Formulation

Abstract

Herein, the synthesis of enzyme-polymer conjugates is reported. Four different activated polymers (mPEG-aldehyde, mPEG-NHS, maltodextrin-aldehyde, carboxymethyl cellulose aldehyde) are conjugated to the surface of protease, α-amylase, and lipase using two different strategies (reductive amination and alkylation with NHS-activated acid). Although the chemical modification of the enzymes is accompanied by losses in enzyme activity (maximum loss 40%), the covalent attachment of polymers increases the thermal stability and the stability in a standard detergent formulation compared to the unmodified enzymes. The enzyme-polymer conjugates are characterized by asymmetrical-flow field-flow fractionation and differential scanning microcalorimetry. Furthermore, it is demonstrated that conjugated enzymes still show performance in a real washing process. Enzyme-polymer conjugates show a potential as a stabilizing system for enzymes in detergents.

Keywords: differential scanning calorimetry (DSC); enzymes; modification; stabilization; surfactants.