Galactooligosaccharide production from pantoea anthophila strains isolated from “Tejuino”, a Mexican traditional fermented beverage

Abstract

Two Pantoea anthophila bacterial strains were isolated from “tejuino”, a traditional Mexican beverage, and studied as β-galactosidase producers for galactooligosaccharides synthesis. Using 400 g/L of lactose, 50°C, and 15 U/mL of β-galactosidase activity with ethanol-permeabilized cells, the maximum galactooligosaccharides (GOS) yield determined by High performance anion exchange chromatography with pulse amperometric detection (HPAEC-PAD) was 136 g/L (34% w/w of total sugars) at 96% of lactose conversion for Bac 55.2 and 145 g/L (36% w/w of total sugars) at 94% of lactose conversion for Bac 69.1. The main synthesized products were the disaccharides allolactose [Gal-β(1 → 6)-Glc] and 6-galactobiose [Galβ-(1 → 6)-Gal], as well as the trisaccharides 30-galactosyl-lactose [Gal-β(1 → 3)-Galβ-(1 → 4)-Glc], 6-galactotriose [Gal-β(1 → 6)-Galβ-(1 → 6)-Gal], 3'-galactosyl-allolactose [Gal-β(1 → 3)-Gal-(1 ! 6)-Glc], and 6'-galactosyl-lactose [Galβ-(1 → 6)-Galβ-(1 → 4)-Glc]. The β-galactosidases present in both strains showed a high transgalactosylation activity and formed principally (1 β 3) and (1 β 6) linkages. Considering the stability and bifidogenic properties of GOS containing such types of bonds, P. anthophila strains Bac 55.2 and Bac 69.1 possess a high potential as novel biocatalysts for prebiotic industrial production.