Utilization of industrial citrus pectin side streams for enzymatic production of human milk oligosaccharides

This study reports the enzymatic upgrading of fucosylated xyloglucan from depectinized citrus residues into 2 ' fucosyllactose, a fucosylated human milk oligosaccharide. Alkaline and enzymatic xyloglucan extractions were compared. Of the original fucose present in the depectinized residues of lemon and orange, 35-36% and 48-51% were extracted as fucosylated xyloglucan by enzyme- or alkaline treatment, respectively. Furthermore, the enzymatically extracted xyloglucan structures had a narrower molecular weight distribution around 1 kDa, contrary to a more polydisperse distribution of the alkaline extracted xyloglucans, ranging from 1 to 500 kDa. The applicability of the fucosylated-xyloglucan extracts in transfucosylation reactions, was determined by use of a selected fungal fucosidase, resulting in yields of 10.2-11.4% enzymatic extracts, and 6.5-7.4% for alkaline extracts (orange and lemon respectively). The results demonstrate that depectinized citrus side streams are a useful source of fucosylated xyloglucan, preferably extracted by an enzyme catalyzed approach.

Automated summary

This study demonstrates the utility of depectinized citrus residues as a valuable source of fucosylated xyloglucan for the production of 2' fucosyllactose. Enzymatic extraction of xyloglucan resulted in a narrower molecular weight distribution compared to alkaline extraction. The enzymatic extracts showed higher yields in transfucosylation reactions, making them preferable for this application.