Production of functional mimics of human milk oligosaccharides by enzymatic glycosylation of bovine milk oligosaccharides

Consumption of mothers' milk is associated with reduced incidence and severity of enteric infections, leading to reduced morbidity in breastfed infants. Fucosylated and sialylated human milk oligosaccharides (HMO) are important for both direct antimicrobial action – likely via a decoy effect – and indirect antimicrobial action through commensal growth enhancement. Bovine milk oligosaccharides (BMO) are a potential source of HMO-mimics as BMO resemble HMO; however, they have simpler and less fucosylated structures. BMO isolated at large scales from bovine whey permeate were modified by the addition of fucose and/or sialic acid to generate HMO-like glycans using high-yield and cost-effective one-pot multienzyme approaches. Quadrupole time-of-flight LC/MS analysis revealed that 22 oligosaccharides were synthesized and 9 had identical composition to known HMO. Preliminary anti-adherence activity assays indicated that fucosylated BMO decreased the uptake of enterohemorrhagic Escherichia coli O157:H7 by human intestinal epithelial Caco-2 cells more effectively than native BMO.