A theor. model is developed for continuous multistage enzyme prodn. systems, which consist of a growth fermentor used for growing microorganisms rapidly without enzyme prodn. and a subsequent system of induction reactors in which enzyme induction and prodn. occurs. The model allows the computation of the fraction of induced cells residing in the induction reactors for organisms exhibiting a lag phase in enzyme induction. For this model a general anal. soln. was obtained for the cumulative internal residence time distribution of a series of n well-stirred vessels with a recycle. The theor. results are compared in a preliminary way with experimentally measured cellulase [9012-54-8] productivities of continuous multistage cellulose fermns. with Trichoderma viride QM 9414. [on SciFinder (R)]