Analysis and control of a biofilm disinfection model

Abstract

The goal of this dissertation is to study a complex biofilm model with a phenotypic structure presented in [34]. The model in [34] is extended - growth and detachment is added, making the new model more interesting in applications. The crucial feature of our model is that cells are able to enter an adapted resistant state when challenged with antimicrobials (adaptation). We study this model in both a qualitative and quantitative manner. Existence and uniqueness of solutions is shown as well as the existence and non-uniqueness of steady-state solutions. Another question of interest is the effective dosing of biocide, i.e. exploring dosing strategies that could minimize the number of living cells or biofilm thickness. Constant and periodic dosing regimes are modeled numerically and studied analytically. One of our main results is that on and off dosing is significantly better than the other dosing types. The model presented in this dissertation contributes to a better understanding of one of the resistant mechanisms in biofilms.