Effect of initial sucrose concentration on the production of beta-fructofuranosidase from Aspergillus japonicus TIT-90076 were investigated in shaking batch cultures. The maximal enzyme production occurred at 25 % (w/v) sucrose and an inhibitory effect on cell growth was exhibited when the initial sucrose concentration was above 10 % (w/v). For evaluation of the process economy, a relationship between the process output (FFase production at 96-h cultivation, in units ml(-1)) and the process input (initial sucrose concentration S-o, in % (w/v)) can be simply expressed as follows : FFase production = (142.9S(o)/(29.3 + S-o))(16.7 - 0.22S(o)).