Purification and characterization of Aspergillus terreus α-galactosidases and their use for hydrolysis of soymilk oligosaccharides

Appl Biochem Biotechnol. 2011 Aug;164(7):1111-25. doi: 10.1007/s12010-011-9198-y. Epub 2011 Feb 18.

Abstract

α-Galactosidases has the potential to hydrolyze α-1-6 linkages in raffinose family oligosaccharides (RFO). Aspergillus terreus cells cultivated on wheat bran produced three extracellular forms of α-galactosidases (E1, E2, and E3). E1 and E2 α-galactosidases presented maximal activities at pH 5, while E3 α-galactosidase was more active at pH 5.5. The E1 and E2 enzymes showed stability for 6 h at pH 4-7. Maximal activities were determined at 60, 55, and 50 °C, for E1, E2, and E3 α-galactosidase, respectively. E2 α-galactosidase retained 90% of its initial activity after 70 h at 50 °C. The enzymes hydrolyzed ρNPGal, melibiose, raffinose and stachyose, and E1 and E2 enzymes were able to hydrolyze guar gum and locust bean gum substrates. E1 and E3 α-galactosidases were completely inhibited by Hg²⁺, Ag⁺, and Cu²⁺. The treatment of RFO present in soy milk with the enzymes showed that E1 α-galactosidase reduced the stachyose content to zero after 12 h of reaction, while E2 promoted total hydrolysis of raffinose. The complete removal of the oligosaccharides in soy milk could be reached by synergistic action of both enzymes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus / chemistry
  • Aspergillus / enzymology*
  • Dietary Fiber / metabolism
  • Dyspepsia / prevention & control
  • Enzyme Stability
  • Food Handling / methods*
  • Galactans / metabolism
  • Glycine max / chemistry*
  • Humans
  • Hydrogen-Ion Concentration
  • Hydrolysis / drug effects
  • Kinetics
  • Mannans / metabolism
  • Melibiose / metabolism
  • Metals, Heavy / pharmacology
  • Oligosaccharides / metabolism
  • Plant Gums / metabolism
  • Raffinose / metabolism
  • Soy Milk / chemistry
  • Soy Milk / metabolism*
  • Substrate Specificity
  • Temperature
  • alpha-Galactosidase* / chemistry
  • alpha-Galactosidase* / isolation & purification
  • alpha-Galactosidase* / metabolism

Substances

  • Dietary Fiber
  • Galactans
  • Mannans
  • Metals, Heavy
  • Oligosaccharides
  • Plant Gums
  • stachyose
  • Melibiose
  • guar gum
  • alpha-Galactosidase
  • Raffinose
  • locust bean gum