Explain why a pH probe is required in a fermenter used for culturing micro-organisms.

It is important to monitor the pH of the fermenter to ensure this acidity can be detected and acid or alkali can be added accordingly to make sure the fermenter is at the optimum pH for the microorganisms. The microorganims in the fermenter will be actively respiring, a product of which is carbon dioxide an acidic molecule. Thus, the fermenter may need to be neutralised with alkali as the microorganisms will grow most effectively at their optimum pH, ensuring maximum efficiency of the fermenter.