Production of β-fructofuranosidase byAspergillus japonicus

A newly isolated strain, MU-2, which produces very high β-fructofuranosidase activity, was identified asAspergillus japonicus. For enzyme production by the strain, sucrose at 20% (w/v) was the best carbon source and yeast extract at 1.5 to 3% (w/v) the best nitrogen source. Total enzymatic activity and cell growth were at maximum after 48 h, at 1.57×10(4) U/flask and 0.81 g dry cells/flask, respectively. The optimum pH value of the enzymatic reaction was between 5.0 and 5.5 and the optimum temperature 60 to 65°C. The enzyme produced 1-kestose (O-β-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl α-D-glucopyranoside) and nystose (O-β-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl-(2→1)-β-D-fructofuranosyl α-D-glucopyranoside) from sucrose by fructosyl-transferring activity. The strain was found to be very useful for industrial production of β-fructofuranosidase.