Biocompatible and magnetic polymers of poly(vinyl pyrrolidone deep eutectic solvent, VP DES) were investigated to determine whether they could efficiently adsorb L-asparaginase, which is an important enzyme inhibiting the growth of certain tumor cells. A series of poly(VP DES)s were successfully obtained, and that based on VP-malonic acid (VP/MA molar ratio of 1:1) was found to be the best for L-asparaginase adsorption. In addition, L-asparaginase was easily separated with biocompatible poly (VP-MA DES) from Escherichia coli extracts under a magnetic field with a high specific activity toward the hydrolysis of L-asparagine, as determined by the Nessler reaction method. Based on this work, poly(VP-MA DES)s seem ideal carriers via adsorption for the delivery of specific enzyme for the biocatalysis. (C) 2019 Elsevier Inc. All rights reserved.