Modelling Bacteria Growth and Reproduction

I am currently working on modelling growth and reproduction of some simple microorganisms. The goal is to construct a self-evolving system that would be able to derive some interesting results which I do not programmatically putting into the system.
The system must satisfy some basic conditions:
- conservation of matter. Microorganisms are living in some finite space filled initially with certain amount of basic organic/inorganic molecules distributed uniformly or somehow else in that space. Each microorganism extracts, metabolize these elements, excrete products of its life into the space and when it dies it releases all its internal stuff as well.
- physics. Each organism has some real physical dimension and thus needs a certain amount of space for itself. Other organisms should not "overlay" atop of each other. The model world is 2D but things like collisions, pressure and other common-sense stuff must be in place there.

I have no time to write a lot right now, need to develop but here is the first video which shows current results in visualization part of the system: