Detailed Analysis of Galactooligosaccharides Synthesis with β‑Galactosidase from Aspergillus oryzae

• Published in: Journal of agricultural and food chemistry Vol. 61; no. 5; pp. 1081 - 1087
• Main Authors: Urrutia, Paulina, Rodriguez-Colinas, Bárbara, Fernandez-Arrojo, Lucía, Ballesteros, Antonio O, Wilson, Lorena, Illanes, Andrés, Plou, Francisco J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 06-02-2013
• Subjects: Aspergillus oryzae; Aspergillus oryzae - enzymology; Bacillus - enzymology; Bacillus circulans; beta-galactosidase; beta-Galactosidase - metabolism; Biological and medical sciences; Disaccharides - biosynthesis; Food industries; Fundamental and applied biological sciences. Psychology; galactooligosaccharides; Hydrogen-Ion Concentration; Kluyveromyces - enzymology; Kluyveromyces marxianus var. lactis; lactose; Lactose - biosynthesis; Magnetic Resonance Spectroscopy; Temperature; Trisaccharides - biosynthesis; galactooligosaccharides; glycosidase; β-galactosidase; prebiotics; transglycosylation; oligosaccharides; Enzyme; Oligosaccharide; Prebiotics; Fungi; Glycosylases; Transglycosylation; Synthesis; Aspergillus oryzae; Glycosidases; Hydrolases; Fungi Imperfecti; β-Galactosidase
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf304354u

The synthesis of galactooligosaccharides (GOS) catalyzed by β-galactosidase from Aspergillus oryzae (Enzeco) was studied. Using 400 g/L of lactose and 15 U/mL, maximum GOS yield, measured by HPAEC-PAD, was 26.8% w/w of total carbohydrates, obtained at approximately 70% lactose conversion. No less than 17 carbohydrates were identified; the major transgalactosylation product was 6′-O-β-galactosyl-lactose, representing nearly one-third (in weight) of total GOS. In contrast with previous reports, the presence of at least five disaccharides was detected, which accounted for 40% of the total GOS at the point of maximum GOS concentration (allolactose and 6-galactobiose were the major products). A. oryzae β-galactosidase showed a preference to form β(1→6) bonds, followed by β(1→3) and β(1→4) linkages. Results were compared with those obtained with β-galactosidases from Kluyveromyces lactis and Bacillus circulans. The highest GOS yield and specific productivity were achieved with B. circulans β-galactosidase. The specificity of the linkages formed and distribution of di-, tri-, and higher GOS varied significantly among the three β-galactosidases.