Immobilized feruloyl esterase from Humicola insolens catalyzes the synthesis of feruloylated oligosaccharides

Abstract

Abstract Ferulic acid acylation of oligosaccharides catalyzed by feruloyl esterases (FAE) is a promising route to produce feruloylated oligosaccharides. However, modulation of FAE synthetic properties is a key step to improve the acylation. The efficiency of H. insolens FAE to catalyze the feruloylation in six different surfactantless microemulsions reaction systems was evaluated. The highest yield (57%) was obtained with xylobiose in n-Hexane/1,4Dioxane/water; however, no significant feruloylation of raffinose and XOS could be achieved in the 1,4 Dioxane-based microemulsions. In contrast, the 2-Butanone-based microemulsions led to broader substrate specificity of FAE-catalysed feruloylation. The use of magnetic non-porous SiMAG-PGL microparticles led to the highest immobilization yield but the retained activity was low; while non-porous FluidMAG PEA nanoparticles resulted in a lower immobilization yield and a higher retention of activity. A good compromise between the immobilization yield and the retained activity was achieved with the porous epoxy-activated supports. Additional modification of the epoxy supports with iminodiacetic acid (IDA), with/without the inclusion of metal-chelate groups, led to higher immobilized FAE activity/gram of support. The feruloylation capacity of immobilized FAE was found to be dependent on the immobilization support.