Process for the purification of lacto-N-neotetraose

A process for purification of LNnT (lacto-N-neotetraose) from a fermentation broth, wherein the process comprises:

• providing a fermentation broth which contains LNnT, biomass, medium components, contaminants and carbohydrates other than LNnT;
• subjecting the fermentation broth to at least one membrane filtration using nanofiltration membranes, thereby providing a filtrated solution containing LNnT;
• subjecting the filtrated solution to at least one simulated moving bed chromatography, thereby providing a purified solution which contains LNnT;
• subjecting the purified solution to at least one crystallization from water, thereby providing a crystal mass which contains LNnT
• wherein the crystallization comprises
• obtaining a mixture of at least two oligosaccharides, containing at least LNnT in a concentration of at least about 50% DSC and such LNnT purity of this mixture is of at least about 60%;
• crystallizing the purified solution obtained from the simulated moving bed chromatography from a starting temperature of at least about 20-30° C. and letting the saturated mass crystallize by cooling down to at least 10-20° C. or at least 0-10° C., or from a starting temperature of at least about 30-40° C. and letting the saturated mass crystallize by cooling down to at least about 20-30° C., at least 10-20° C. or at least 0-10° C., or from a starting temperature of at least about 40-50° C. and letting the saturated mass crystallize by cooling down to at least about 30-40° C. to at least about 20-30° C., at least 10-20° C. or at least 0-10° C., or from a starting temperature of at least about 50-60° C. and letting the saturated mass crystallize by cooling down to at least 40-50° C., at least about 30-40° C., at least about 20-30° C., or at least about 10-20° C., or at least about 0-10° C. to obtain a homogeneous crystal mass;
• treating the crystal mass with a mixture of an alcohol, solvent, or water-miscible alcohol or solvent and water, wherein the alcohol or solvent content of the solution is between 10 and 90 vol. % to obtain a mixture of the alcohol or solvent-containing solution and the crystal mass;
• and
• at least one washing of the alcohol or solvent-containing or sugar-containing fraction of the crystal mass in order to reduce content of lower saccharides from the crystal mass;
• and
• subjecting such crystal mass to at least one homogenization, wherein the homogenization step is selected from freeze-drying, spray-drying, roller or drum drying and band drying, thereby providing a homogenized and dried purified LNnT;
• wherein the purified preparation contains the LNnT with a purity of ≥80%.