α-L-Fucosidases and their applications for the production of fucosylated human milk oligosaccharides.

α-L-Fucosidases (EC 3.2.1.51), catalyzing the hydrolysis of fucosides and/or the transfer of fucosyl residue, have been characterized and modified into a trans-fucosylation mode or, further, engineered to function as "fucosynthase", which can be employed for the enzymatic synthesis of bioactive glycans, including fucosylated human milk oligosaccharides (HMOs). More than half of HMOs are fucosylated and have attracted ever-increasing interest because of their excellent physiological functions on breast-fed infants. To date, the characterization of novel fucosidases and molecular modification of these enzymes have been extensively studied to efficiently synthesize valuable fucosylated compounds. Herein, we discuss the advantages and challenges of different strategies for the production of HMOs and compare various donor/acceptor substrates used for the synthesis of fucosylated HMOs and their biomimetics. The implementation of trans-fucosylation patterns investigated in this paper via well-designed fucosidase mutants and proper reaction conditions may lead to development of an excellent platform, serving both fundamental studies and industrial-scale processes, for valuable carbohydrates synthesis.Key Points• Highlights different approaches for the production of human milk oligosaccharides.• Summarizes α-l-fucosidases and their mutants in enzymatic synthesis of fucosylated human milk oligosaccharides and the biomimetics.• Concludes future perspectives on methods for improving fucosylated compounds synthesis.• Highlights different approaches for the production of human milk oligosaccharides.• Summarizes α-l-fucosidases and their mutants in enzymatic synthesis of fucosylated human milk oligosaccharides and the biomimetics.• Concludes future perspectives on methods for improving fucosylated compounds synthesis.