The application of biocatalysis to synthesis is limited by the longevity and stability of enzyme catalysts, particularly in non-aqueous solvents. The immobilization of enzymes on solid supports has been demonstrated to improve stability and efficiency of biocatalysts, but often relies on multiple chemical steps for robust covalent attachment. Here, we present a single-step purification and ionic immobilization of a genetically cationized organophosphate hydrolase (OpdA) from Agrobacterium radiobacter and demonstrate its enhanced stability towards non-aqueous solvents, as well as its application to enantioselective hydrolysis in flow. This ionically immobilized catalyst has appeal for industrial application, where rapid production and enhanced longevity are vital to economical large-scale processes.