Optimal Biofilm Featues: metabolic and geometric response to multiple oxidants

Tuesday, 16 December 2014
Chris Kempes1,2, Chinweike Okegbe3, Zwoisaint Mears-Clarke3, Michael J Follows4 and Lars Dietrich3, (1)SETI Institute Mountain View, Mountain View, CA, United States, (2)California Institute of Technology, Pasadena, CA, United States, (3)Columbia University of New York, Palisades, NY, United States, (4)Massachusetts Inst Tech, Cambridge, MA, United States
An important challenge in understanding complex microbial mat communities is determining how groups of a single species balance metabolic requirements with the dynamics of resource supply. We have investigated this problem in the context of redox resources within a single-species bacterial biofilm. We developed a mathematical model of oxidant availability and metabolic response within biofilm features and we show that observed biofilm geometries maximize cellular reproduction and growth efficiency. Our model accurately predicts the measured distribution of two types of electron acceptors: oxygen, which is available from the environment, and phenazines, redox-active small molecules produced by the bacterium. Because our model is based on resource dynamics, we are also able to predict observed shifts in feature geometry based on changes in the availability of redox resources such as variations in the external availability of oxygen or the removal of phenazines. This analysis suggests various avenues for understanding microstructure and the evolution of spatial metabolism in microbial mats.