Preparation of galacto-oligosaccharides using membrane reactor

Abstract Galacto-oligosaccharides (GOS) have many biological functions. They are produced from lactose by a glycosyl transfer of one or more d -galactosyl units onto the d -galactose moiety of lactose catalysed by β-galactosidase. This reaction can proceed in batch or in continuous system. Membrane reactor with ultrafiltration ceramic membrane (150 kDa) was used and batch system as well. Lactose in phosphate buffer (197.9 g L −1 ), recombined whey (197 g L −1 ) and evaporated ultrafiltration permeate (200.7 g L −1 ) were used as substrates. The used concentration of enzyme Maxilact LX 5000 was 6 U mL −1 . The highest concentration of GOS in buffer was reached after 30 min of batch reaction and it was 25.5 g L −1 , for recombined whey it was 31.1 g L −1 and for ultrafiltration permeate it was 32.9 g L −1 . For continuous process was obtained 8.8 g L −1 of GOS for buffer and 21.0 g L −1 for recombined whey and 16.7 g L −1 of GOS for ultrafiltration permeate.