Production of β-Fructofuranosidase from Aspergillus niger ATCC 20611

บทคัดย่อ

An increase in magnesium sulfate decreased the ratio of extracellular/intracellular β- fructofuranosidase activity in shaking flask cultivation of Aspergillus niger ATCC 20611. At 0.4% MgSO₄ concentration, the enzyme ratio was decreased to 54%, but the total enzyme activity was increased 1.12 times more than that with no salt addition. Three ammonium salts tested, (NH₄)₂SO₄, (NH₄)₂HPO₄, and NH₄NO₃ could not substitute yeast extract as a nitrogen source because of decreasing in the specific growth rate, enzyme yield and productivity. In this study, yeast extract with vitamin solution gave the highest values of specific growth rate, enzyme yield and productivity. Based on the fermentation kinetic study in aerobic batch culture under controlled pH and temperature, the specific growth rate, enzyme yield and productivity were improved to 0.0414 h^-1, 65.16 × 10³ U/g sucrose and 1.89 × 10³ U/g cell h, respectively. These values were increased 1.85, 10.5 and 497.9 times, respectively, comparing with shaken flask culture.