A fundamental analysis of continuous flow bioreactor and membrane reactor models with non‐competitive product inhibition. III. Linear inhibition

Abstract

The steady-state production of a product produced through the growth of microorganisms in a continuous flow bioreactor is presented. A generalised reactor model is used in which both the classic well-stirred bioreactor and the idealised membrane bioreactor are considered as special cases. The reaction is assumed to be governed by Monod growth kinetics subject to non-competitive product inhibition. Inhibition is modelled as a decreasing linear function of the product concentration with a finite cut-off. This reaction scheme is well documented in the literature, although a stability analysis of the governing equations has not previously been presented.The steady-state solutions for the models have been obtained, and the stability has been determined as a function of the residence time. The key dimensionless parameter (γ ) that controls the degree of non-competitive product inhibition is obtained by scaling of the equations, and its effect on the reactor performance is quantified in the limit when product inhibition is 'small' and 'large'. The parameter γ is the reciprocal of a scaled inhibition constant (P m ) that depends upon the substrate and product yield factors and the Monod constant (γ = α s α p · K s P m ).  352 346 Asia-Pacific Journal of Chemical Engineering AN ANALYSIS OF CONTINUOUS FLOW BIO-REACTORS WITH COMPETITIVE Stability of the washout solutionThe Jacobian matrix evaluated at the washout steadystate solution is given by J (S * 0 , 0, 0) =

A fundamental analysis of dynamics of waste biodegradation in aerobic processes

“…Bioreactors are in fact known to exhibit a number of nonlinear phenomena. These include bistability between nontrivial steady states and washout, the occurrence of multiple steady states (the famous hysteresis phenomenon) as well as the occurrence of oscillations . The mechanisms of most of these phenomena are not well understood, but they are known to be strongly dependent on the inherent mechanisms of the biodegradation (growth kinetics and yield coefficients) as well as on operating parameters of the process (feed flow rate, feed concentration, recycle ratio…etc.…”