Promising biocatalysts for producing lactose-free food matrices: β-galactosidase immobilized on cellulose-rich agro-industrial waste supports

This study aimed to develop, characterize, and apply wheat husk and rice husk-based supports for immobilizing β-galactosidase (β-gal) tagged with a Cellulose Binding Domain (β-gal-CBD) in column reactors. Biocatalysts were applied in skim milk hydrolysis in two column reactor configurations: balls column reactor (BCR) and toothed column reactor (TCR). Spheres containing 15 % rice and wheat husk powders showed 10× and 25× increased hardness, respectively, compared to controls. Wheat husk-added core-shell capsules had the highest structural resistance. Immobilization of β-gal-CBD onto supports (3 U/sphere or 3 U/capsule) was achieved in 15 min, with yield and efficiency values of up to 90 %. After 48 h of continuous reaction in column reactors, the developed biocatalysts maintained over 55 % of their relative hydrolysis values, indicating significant stability. Utilizing these residues for enzyme immobilization supports introduces a novel application, contributing to waste reduction and adding value to agro-industrial residues while enhancing enzymatic biocatalysis.