COMPLEX DYNAMICS IN A DISCRETE-TIME SIZE-STRUCTURED CHEMOSTAT MODEL WITH INHIBITORY KINETICS

An inhibitory uptake function is incorporated into the discrete, size-structured nonlinear chemostat model developed by Arino et al. (Journal of Mathematical Biology, 45(2002)). Different from the model with a mono-tonically increasing uptake function, we show that the inhibitory kinetics can induce very complex dynamics including stable equilibria, cycles and chaos (via the period-doubling cascade). In particular, when the nutrient concentration in the input feed to the chemostat S-0 is larger than the upper break-even concentration value mu, the model exhibits three types of bistability allowing a stable equilibrium to coexist with another stable equilibrium, or a stable cycle or a chaotic attractor.