Sustainable synthesis of N-acetyllactosamine using an immobilized β-galactosidase on a tailor made porous polymer

Abstract

Porous polymer particles containing surface epoxy groups were synthesized for immobilizing β-galactosidase from Bacillus circulans. Enzyme immobilization was achieved by covalent attachment to a custom made porous polymer and the biocatalyst was characterized in terms of optimal pH and thermal stability, and its catalytic efficiency evaluated for synthesizing N-acetyllactosamine (Gal-β-(1 → 4)-GlcNAc) in different solvents and using a 1 : 5 molar ratio of donor (pNP-β-Gal) : acceptor (GlcNAc). The reaction proceeded with high conversion rates and regioselectivity. Yields up to 60% of β-(1 → 4) with biosolvent 3 were found. Reusability assays were performed with the same reaction conditions finding that the immobilized enzyme retains about 85% of its activity after twenty batches with conversion yields above 60%. Furthermore, reaction scale up, biosolvent recovery and recycling are achieved retaining catalytic activity.