Recent progress on galacto-oligosaccharides synthesis by microbialβ-galactosidase——A review
微生物酶法合成低聚半乳糖的新进展

Galacto-oligosaccharides are among the most promising non-digestible oligosaccharides that are recognized as prebiotics. Commercial GOS are synthesized from lactose using the transglycosylation activity of b-galactosidase from microorganisms. The structure of GOS varies with different enzyme source. The oligosaccharide yields of GOS produced by natural enzymes are generally 20%~45% and they could be improved by artificial enzyme. Reaction conditions also have effect on the oligosaccharide yield. Using enzymes in water-hydrophobic solvent mixtures or reverse micelles may improve the yield to some extent. GOS can be large-scale synthesized by packed bed reactor, plugflow reactor or membrane reactor. The glucose and lactose in the GOS products can be removed by using chromatography, enzyme oxidation, nanofiltration membrane or microbial fermentation.