In this paper we develop a macroscopic evolutionary equation for the growth
of the cellular phase starting from a microscopic description of mass tran
sport: and a simple structured model for product formation. The methods of
continuum mechanics and volume averaging are used to develop the macroscopi
c representation by carefully considering the fluxes of chemical species th
at pertain to cell growth. The concept of structured models is extended to
include the transport of reacting chemical species at: the microscopic scal
e. The resulting macroscopic growth model is similar in form to previously
published models for the transport of a single substrate and electron donor
and for the production of cellular mass and exopolymer. The method of volu
me averaging indicates under what conditions the developed growth model is
valid and provides an explicit connection between the relevant microscopic
model parameters and their corresponding macroscopic counterparts. (C) 1999
John Wiley & Sons, Inc.