Nothing particularly new about this. Problems with fuel storage has been
around a long time. (You should see how carefully they filter the fuel
before it goes into aircraft - can't have little bunches of bugs
clogging up the works).
The organisms (bacteria usually) do not actually grow IN the fuel but
some can survive in the moisture that is almost always around.
Condensation from the atmosphere would take place in most storage tanks
when they are only partially filed and that is all it needs. The problem
is that although the organisms will only degrade a tiny amount of fuel,
the biomass they form (biofilms etc etc) can "drop off" into the fuel
and cause problems of blockages.