β-galactosidase GALA from with high transgalactosylation activity.

β-galactosidase catalyzes lactose hydrolysis and transfers reactions to produce prebiotics such as galacto-oligosaccharides (GOS) with potential applications in the food industry and pharmaceuticals. However, there is still a need for improved transgalactosylation activity of β-galactosidases and reaction conditions of GOS production in order to maximize GOS output and reduce production costs. In this study, a β-galactosidase gene, , from was expressed in , which not only hydrolyzed lactose but also had strong transgalactosylation activity to produce GOS.