Comparative analysis of the enzymatic synthesis of lactulose in batch and fed-batch systems

Abstract

β-Galactosidases catalyze hydrolysis and transgalactosylation reactions, the latter allowing the synthesis of prebiotic transgalactosylated oligosaccharides (TOS), such as galacto-oligosaccharides (GOS) and lactulose. The enzymatic synthesis of lactulose from lactose and fructose is still a scarcely explored field and most reported yields are low (Figure 1). ❖ Synthesis in fed-batch mode is proposed for increasing the yield of lactulose synthesis. Fed-batch operation has been applied to bioprocesses where the concentration of a medium component needs to be controlled. Lactulose synthesis keeping lactose and fructose concentrations controlled at certain levels should result in a yield increase by favoring transgalactosylation over hydrolytic activity.