Ethanol is a great preservation medium for molecular recovery, it's commonly used to store environmental, fecal, etc samples for microbial identification. 70% is a bit low for longer term preservation, but for only 6 months, you should get good recovery; but consider that consumed bacteria in free-association or particle-bound are exposed to digestive enzymes, so depending on the load and pre-preservation conditions/procedures, there may be variable amounts of recoverable macromolecules of interest.