Reactor scale modeling of quorum sensing induced biofilm dispersal

We present a simple reactor-scale mathematical model of active biofilm dispersal that is controlled by a quorum sensing system. The model is cast as a system of three ordinary differential equations for the dependent variables biofilm thickness, quorum sensing sig-nal concentration in the reactor, and concentration of the growth limiting substrate in the reactor. The model is investigated with analytical and numerical techniques. We find that a single QS dispersal mechanism, depending on parameters, can lead to (i) continuous cell loss at a signal level at which the biofilm is entirely up-regulated, (ii) periodically repeating almost instantaneous cell loss with the biofilm switching between down-and up-regulated states, (iii) continuous cell loss at a signal level at which the biofilm is entirely down-regulated, or (iv) complete washout. We contrast this with a simple model of starvation induced dispersal, which is cast in the same modeling framework, but shows entirely dif-ferent dynamic behavior, in that it only permits washout or asymptotic convergence to a steady state at break-even concentration, depending on parameters.(c) 2021 Elsevier Inc. All rights reserved.

Automated summary

A simple reactor-scale mathematical model of active biofilm dispersal controlled by a quorum sensing system is presented. The model examines different cell loss patterns depending on the level of the quorum sensing signal and the state of the biofilm. A comparative study with a starvation induced dispersal model reveals distinct dynamic behaviors.