N. Li, Z.N. Wang, T.J. Qu, J. Kraft, J.-H. Oh, J.P. van Pijkeren, G.W. Huber, and X.J. Pan. High-yield synthesis of glucooligosaccharides (GlOS) from glucose via non-enzymatic glycosylation as potential prebiotics. Green Chemistry, 2019, 21, 2686-2698. https://doi.org/10.1039/C9GC00663J
This study demonstrated a high-yield process to synthesize glucooligosaccharides (GlOS) from glucose via non-enzymatic glycosylation in an acidic lithium bromide trihydrate (ALBTH, a concentrated aqueous solution of LiBr containing a small amount of acid) system. The single-pass yield of the GlOS was up to 75%, which was the highest yield ever reported. The synthesized GlOS consisted of 2-9 glucose units linked predominantly via α/β–1,6 glycosidic bonds (69%), followed by α/β–1,3, α/β–1,2, α/β–1,1, and α–1,4 glycosidic bonds. Preliminary in-vitrofermentation tests indicated that GlOS could be utilized by select gut probiotic strains, suggesting that GlOS had the potential as prebiotics. Theenhanced glucose glycosylation in ALBTH was attributedto the unique properties of the solvent system, including water-deficient nature, extra-highcapacity of dissolving glucose,and enhanced acid catalysis. The LiBr salt could be recovered after separating the GlOS by anti-solvent precipitation and directly reused.