Why do anaerobic bacteria require a low redox potential for their culture media? I'm reading _Clostridium_ ,which is an anaerobic bacteria in my microbiology text and it says, > of more importance than the absence of oxygen is the provision of a sufficiently low redox potential in the medium. Third can be achieved by adding unsaturated fatty acids, ascorbic acid, glutathione, cysteine, etc. Why? Do they reduce oxygen free radicals or something? Well, are these present in _Clostridium_ 's natural habitat?

The higher the redox potential is, the higher the oxygen dissolved in the media will be. Lowering this potential insure that the oxygen concentration is lower and that the anaerobe will be able to grow easily.

Several steps can be done while preparing the media such as boiling to remove oxygen and adding chemical which reduces this redox potential to dissolve oxygen back into the medium.

As for the natural habitat, they naturally have no or really really low amounts of oxygen. If the habitats containing little oxygen have other molecules able to reduce redox potential is a good question.

Lowering the redox potential is mainly important for the medium since there is oxygen involved (hard to remove 100% while preparing media).

I hope my answer helps.