Functionalized polyacrylonitrile particles as a promising support for the immobilization of laccase from Trametes versicolor

Abstract

This work evaluates the potential of polyacrylonitrile particles (PAN) as support for laccase from Trametes versicolor immobilization. The slurry polymerization method forms mesoporous particles with low surface area and low maximum pore volume in desorption. The particles were chemically modified by consecutive alkaline and acid hydrolysis, followed by amination and activation with glutaraldehyde to enzyme immobilization. The laccase immobilization yield was 99.48% and 14.29% using the functionalized and non-functionalized particles, respectively. The enzyme activity was measured by the oxidation of 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) at different pHs and temperatures. The PAN/laccase derivative was hyperactivated at pH 3, up to 3 times higher than the free enzyme, and performed better at 50°C after 6 h of incubation, with relative activity up to 33% higher than the free enzyme. However, both enzymes denatured when the conditions reached pH 8 and 70°C. The PAN/laccase retained 89% of the initial activity after 30 days of storage at 5°C. It was possible to reuse the enzymatic derivative for 5 cycles, with up to 50% residual activity, under 50°C and pH 3. These results show the potential of this new support for laccase immobilization and further applications of industrial interest.