Nonlinear development of bacterial colony modeled with cellular automata and agent objects

Despite a number of different numerical techniques existing for modeling the uptake of the nutrients, metabolism, maintenance, cell division and growth of bacteria population, none of them can be treated as a universally one. In this new model we have combined two techniques. The first one - agent-based - has been used for modeling the behavior of an individual bacterium. The agent objects (AOs) define generic features of the bacterium and the ways they interact with the environment and with the neighboring bacteria. The cellular automata are used for modeling the bacterial environment and represent communication layer for the agents, while a fixed two-dimensional grid defines the living space. The growth of the bacterial colony depends on the amount of free space in the closest neighborhood of individuals, which is required for reproduction, and on the availability of nutrients. We have matched the parameters of the model to demonstrate various growth structures developed by bacteria populations. We show that the patterns generated by the bacteria due to their collective behavior reflect the dynamical vitality of population and its fitness factor. We observe that the strongest populations self-organize in rod-like structures, which are reproduced in experimental microscopy images characteristic for bioflims and anthrax bacterial colonies.