Amylase production by solid state culture of Aspergillus oryzae on polyurethane foams. Some mechanistic approaches from an empirical model

Using systems formed by particles of polyurethane foam of different densities soaked in an amylaceous effluent, the production of amylases by Aspergillus oryzae in solid state culture was studied by a complete factorial plan with four variables - support density, particle diameter, volume of liquid phase and substrate concentration. The empirical model obtained is consistent and allows a simple control of the response, superior in several respects to that of the corresponding submerged cultures. Moreover, it enables a mechanistic approach to the behaviour of the system, whose principal kinetic characteristics can be interpreted in terms of intra- and interparticular diffusional effects, which have a determining influence on basic state variables, such as water activity and gas transfer. Copyright (C) 1996 Elsevier Science Ltd