Reaction kinetics and galactooligosaccharide product profiles of the β-galactosidases from Bacillus circulans, Kluyveromyces lactis and Aspergillus oryzae. (15th June 2017)

• Record Type: Journal Article
• Authors: Yin, Huifang; Bultema, Jelle B.; Dijkhuizen, Lubbert; van Leeuwen, Sander S.
• Is Part Of: Food chemistry. Volume 225(2017)
• Page Start: 230
• Page End: 238
• Publication Date: 2017-06-15
• Subjects: GOS galactooligosaccharides -- HPAEC-PAD high-pH anion-exchange chromatography coupled with pulsed amperometric detection -- NMR nuclear magnetic resonance -- MALDI-TOF-MS matrix assisted laser desorption/ionization-time of flight mass spectrometry -- Gal galactose -- Glc glucose -- Lac lactose; Bacillus circulans -- Kluyveromyces lactis -- Aspergillus oryzae -- Galactooligosaccharides -- β-Galactosidase -- Infant nutrition -- Prebiotics; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2017.01.030
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: GOS biosynthesis routes were mapped for 3 commercial β-galactosidase enzymes. Lactose isomer synthesis is based on the acceptor reaction with Glc. Addition of Gal or Glc changed the GOS profiles. β-Galactosidase from Bacillus circulans has a relatively high GOS yield and product complexity. Abstract: β-Galactosidase enzymes are used in the dairy industry to convert lactose into galactooligosaccharides (GOS) that are added to infant formula to mimic the molecular sizes and prebiotic functions of human milk oligosaccharides. Here we report a detailed analysis of the clearly different GOS profiles of the commercial β-galactosidases from Bacillus circulans, Kluyveromyces lactis and Aspergillus oryzae . Also the GOS yields of these enzymes differed, varying from 48.3% ( B. circulans ) to 34.9% ( K. lactis ), and 19.5% ( A. oryzae ). Their incubation with lactose plus the monosaccharides Gal or Glc resulted in altered GOS profiles. Experiments with 13 C6 labelled Gal and Glc showed that both monosaccharides act as acceptor substrates in the transgalactosylation reactions. The data shows that the lactose isomers β-d -Gal p -(1 → 2)-d -Glc p, β-d -Gal p -(1 → 3)-d -Glc p and β-d -Gal p -(1 → 6)-d -Glc p are formed from acceptor reactions with free Glc and not by rearrangement of Glc in the active site.