Bifidobacterial β-galactosidase-mediated production of galacto-oligosaccharides: structural and preliminary functional assessments

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Ambrogi, Valentina
Bottacini, Francesca
MacSharry, John
van Breen, Justin
O’Keeffe, Ellen
Walsh, Dan
Schoemaker, Barry
Cao, Linqiu
Kuipers, Bas
Lindner, Cordula
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In the current study the ability of four previously characterized bifidobacterial β-galactosidases (designated here as BgaA, BgaC, BgaD, and BgaE) to produce galacto-oligosaccharides (GOS) was optimized. Of these enzymes, BgaA and BgaE were found to be promising candidates for GOS production (and the corresponding GOS mixtures were called GOS-A and GOS-E, respectively) with a GOS concentration of 19.0 and 40.3% (of the initial lactose), respectively. GOS-A and GOS-E were partially purified and structurally characterized. NMR analysis revealed that the predominant (non-lactose) disaccharide was allo-lactose in both purified GOS preparations. The predominant trisaccharide in GOS-A and GOS-E was shown to be 3′-galactosyllactose, with lower levels of 6′-galactosyllactose and 4′-galactosyllactose. These three oligosaccharides have also been reported to occur in human milk. Purified GOS-A and GOS-E were shown to be able to support bifidobacterial growth similar to a commercially available GOS. In addition, GOS-E and the commercially available GOS were shown to be capable of reducing Escherichia coli adhesion to a C2BBe1 cell line. Both in vitro bifidogenic activity and reduced E. coli adhesion support the prebiotic potential of GOS-E and GOS-A.
Bifidobacterium , Prebiotics , Gut microbiota , Microbiome , Bifidogenic , Infant , Oligosaccharides
Ambrogi, V., Bottacini, F., Mac Sharry, J., Van Breen, J., O’Keeffe, E., Walsh, D., Schoemaker, B., Cao, L., Kuipers, B., Lindner, C., Jimeno, M.L., Doyagüez, E.G., Hernandez-Hernandez, O., Moreno, F.J., Schoterman, M. and Van Sinderen, D. (2021) ‘Bifidobacterial β-galactosidase-mediated production of galacto-oligosaccharides: structural and preliminary functional assessments’, Frontiers in Microbiology, 12, 750635 (19pp). doi: 10.3389/fmicb.2021.750635