Microbes that eat hydrocarbons and are environmentally safe.

[Roger J. Young]

>After years of research at the University of Texas, a blend of 13 microbes 
>collected from natural oil seeps around the world has been compiled.

I would be interested to know how one would manage to keep such a blend 
stable, ie. preventing one species from overrunning the others. Would you 
create a new mix/batch just before deployment ? If stable, how would you 
ensure that such a population doesn't contaminate deliberate stores of 
hydrocarbons?
(This is all good stuff for the Microbial Ecology part of my course.)
TIA

Rog.