*2.3. Refining of Oligosaccharides by Membrane Processing*

AL obtained under optimal conditions for OS production was refined by discontinuous diafiltration (DD). Assays were performed in a stirred Amicon cell (Millipore) operating at a transmembrane pressure of 3.5 bar and room temperature. Water was added to AL at 2:1 volume ratio, diafiltered through a 0.3 kDa cutoff membrane (GE Osmonics Inc., Minnetonka, MN, USA) up to achieve a retentate volume equal to one of the feed. Samples from retentate and permeate were assayed for composition (using the same methodology as described in Section 2.4) and structural features.
