Lactose monohydrate and acetonitrile (HPLC grade) were supplied by VWR (Barcelona, Spain). MOPS (3-(N-morpholino) propanesulfonic acid), xylitol, phenyl-βglucoside, maltulose, maltose, cellobiose, mannitol, sorbitol, sucrose, and pNP-β-Dgalactopyranoside were purchased from Sigma Aldrich (Stenheim, Germany).
Erythritol, isomaltulose, gentiobiose, isomaltose, lactulose and 2'-fucosyl-lactose, were purchased from Carbosynth (Berkshire, UK). KH2PO4 and K2HPO4 were supplied by Merck (Steinheim, Germany). All other chemicals were of analytical grade. The hydrolytic activity of LacA β-galactosidase (1.16 U mL -1 ) was also assayed by incubation at 30⁰C of different carbohydrates such as lactose, lactulose, cellobiose, gentiobiose, maltose, isomaltulose and sucrose at 200 g L -1 with 300 μL of enzyme in 50 mM of MOPS buffer supplemented with 20 mM of NaCl (pH=7) to a final volume of 1 mL. In the case of 2-fucosyl-lactose, isomaltose, nigerose and maltulose the concentration was 0.5 g L -1 . Reactions were stopped at 24 hours by heating at 100ºC for 5 min and samples were stored at -20⁰C for the subsequent analysis. Reactions were carried out in triplicate (n = 3). All these hydrolytic reactions were monitored by GC-FID.
Erythritol, isomaltulose, gentiobiose, isomaltose, lactulose and 2'-fucosyl-lactose, were purchased from Carbosynth (Berkshire, UK). KH2PO4 and K2HPO4 were supplied by Merck (Steinheim, Germany). All other chemicals were of analytical grade. The hydrolytic activity of LacA β-galactosidase (1.16 U mL -1 ) was also assayed by incubation at 30⁰C of different carbohydrates such as lactose, lactulose, cellobiose, gentiobiose, maltose, isomaltulose and sucrose at 200 g L -1 with 300 μL of enzyme in 50 mM of MOPS buffer supplemented with 20 mM of NaCl (pH=7) to a final volume of 1 mL. In the case of 2-fucosyl-lactose, isomaltose, nigerose and maltulose the concentration was 0.5 g L -1 . Reactions were stopped at 24 hours by heating at 100ºC for 5 min and samples were stored at -20⁰C for the subsequent analysis. Reactions were carried out in triplicate (n = 3). All these hydrolytic reactions were monitored by GC-FID.