Regular articleA spatially explicit model of inverse colony formation of cellulolytic biofilms

•A spatially explicit mathematical model for cellulosic biofilms is proposed.•It is based on the basic principle of competition for space and resources.•It captures experimentally observed behavior of cellulosic biofilms.•Attachment of cells from the aqueous phase can be incorporated as a random process.

We propose a spatially explicit mathematical model for the formation of cellulolytic biofilms. It consists of a highly nonlinear degenerate coupled PDE-ODE system for the bacteria that colonise the cellulosic substratum, and for the carbon source that is immobilised in the reactive substratum. Computer simulations show that the model is able to reproduce important features of cellulolytic biofilms that have been reported in the experimental literature. These include the formation of inverse colonies, crater-like colonies, degradation of paper chads at constant speed (which correspond to a traveling wave solution of the model), and temporal CO2 production pattern.