Production of Galacto-Oligosaccharides by Enzymatic Membrane Reactors Using Free β-Galactosidase

Prebiotic galacto-oligosaccharides (GOSs) are synthesized by transgalactosylation of lactose using beta-galactosidases. Well-established, large-scale production of GOS is performed by stirred-tank reactors (STR) operating in batch fashion. Main manufacturing expenses are attributed to enzyme purchase costs and the downstream operations required for subsequent enzyme inactivation and removal. In the last decades, several studies and patents have appeared on free enzyme membrane reactor (FEMR) as an economic alternative to STR due to enhanced enzyme recovery and reuse. In this review, we attempt to summarize the key design aspects, the catalytic performance and efficiency of FEMR compared to STR technology, and the main concerns related to stable product quality over long-term operation.