Section: Bilateral Contracts and Grants with Industry

DISCO

Participants : Fabien Campillo, Chloé Deygout, Bart Haegeman, Jérôme Harmand, Annick Lesne, Claude Lobry, Alain Rapaport, Tewfik Sari.

DISCO (Multi-scale modelling bioDIversity Structure COupling in biofilms) is a three years project funded by the ANR SYSCOMM since the end of 2009, that aims at developing and studying computational and mathematical models of biofilm dynamics, taking into account the biodiversity (distribution of bacteria species) and spatial structure; see details in https://sites.google.com/site/anrdisco/ .

Several “go back” between simulation models and experiments in plug-flow reactors performed at IRSTEA Antony have been conducted during the two postdoctoral years of C. Deygout hired by the project. A first paper on the simulation of a multi-scale model has been published [17] and a second one on the confrontation with experiments is in preparation (see Section 6.2.2 ).

At a macro-scale, the team has studied several extensions of the chemostat model dedicated to microbial ecosystems with biofilm (see Section 6.1.1 and the publication [21] ).

A new collaboration has been launched with the HBAN team at IRSTEA Antony, within this project, about the modelling of cellulose degradation. Cellulose is typically available in small balls (but ten times larger than the average size of microorganisms) that are first converted by enzymatic activity into carbon substrate that can then be assimilated by the microorganisms. Some of the microorganisms are attached to these balls, creating a particular aggregates structure.

An IBM for the degradation of one cellulose bead (dozens of micrometers in diameter) by cellulolytic bacteria has been developed. Our aim is to determine the macroscopic degradation behavior. The initial stages of the degradation process may involve a very limited number of bacteria that cannot be properly modelled by classical models based on deterministic equations (see Section 6.2.3 and communications [44] and [43] ).

The duration of the project has been extended by the ANR to May 2013, in order for the team to prepare a final restitution at Paris in spring 2013.