Production and Digestibility Studies of β-Galactosyl Xylitol Derivatives Using Heterogeneous Catalysts of LacA β-Galactosidase from Lactobacillus Plantarum WCFS1

Abstract

The synthesis of β-galactosyl xylitol derivatives using immobilized LacA β-galactosidase from Lactobacillus plantarum WCFS1 is presented. These compounds have the potential to replace traditional sugars by their properties as sweetener and taking the advantages of a low digestibility. The enzyme was immobilized on different supports, obtaining immobilized preparations with different activity and stability. The immobilization on agarose-IDA-Zn-CHO in the presence of galactose allowed for the conserving of 78% of the offered activity. This preparation was 3.8 times more stable than soluble. Since the enzyme has polyhistidine tags, this support allowed the immobilization, purification and stabilization in one step. The immobilized preparation was used in synthesis obtaining two main products and a total of around 68 g/L of β-galactosyl xylitol derivatives and improving the synthesis/hydrolysis ratio by around 30% compared to that of the soluble enzyme. The catalyst was recycled 10 times, preserving an activity higher than 50%. The in vitro intestinal digestibility of the main β-galactosyl xylitol derivatives was lower than that of lactose, being around 6 and 15% for the galacto-xylitol derivatives compared to 55% of lactose after 120 min of digestion. The optimal amount immobilized constitutes a very useful tool to synthetize β-galactosyl xylitol derivatives since it can be used as a catalyst with high yield and being recycled for at least 10 more cycles.

Enzymatic Glycosylation Strategies in the Production of Bioactive Compounds

“…In another study, the one-step glycosylation of flavonoids was investigated [40]. One strain of Isaria fumosorosea KCH J2 and two strains of I. farinosa (J1.4 and J1.6) were used as biocatalysts for the glycosylation of 3-hydroxyflavone, 3-methoxyflavone, quercetin (3,3 ,4 ,5,7-pentahydroxyflavone), and baicalein (5,6,7-trihydroxyflavone) [41]. For all the substrates that were used in this study, 4-O-methylglucopyranosides were obtained and the authors suggested that the attachment of 4-O-methylglucopyranose occurs in one step.…”

“…The synthesis was performed using lactose as a donor and good yields for all the interesting compounds were obtained. The in vitro intestinal digestibility of the main β-galactosyl xylitol derivatives was lower than that of lactose, being around 6 and 15% for the galacto-xylitol derivatives compared to 55% for lactose after 120 min of digestion [41]. Another interesting example has been described in the stereoselective glycosylation of epothilones.…”