Preparation of lignin derivatives and their application as protease adsorbents

Abstract

Synthesis of two lignin derivatives, lignophenol and lignin-aminophenol, were presented in this article. The chemical structure and the func-tional groups of lignin derivatives were charac-terized through FT-IR analysis. The immobiliza-tion of three proteases (papain, trypsin and pepsin) on lignin and lignin derivatives was carried out using adsorption technique. The influence of contact time and pH on the enzyme adsorption by different adsorbents was inves-tigated. Furthermore, enzyme activity recovery was also evaluated. Results showed that lignin and lignin derivatives could adsorb proteases effectively and the adsorption capacity of lingo- phenol and lignin-aminophenol was higher than that of pure lignin. Meanwhile, the activity re-covery of papain and pepsin immobilized on lignin derivatives was very high. This pheno- menon suggested that there is a supramole- cular interaction between enzymes and lignin derivatives which do not inhibit enzyme activity. Therefore, lignophenol and lignin-aminophenol are both promising adsorbents for enzyme im-mobilization under acid and neutral conditions.