In which pH range do methane fermenters typically operate?

Methane fermenters, or methanogenic microorganisms, thrive in a pH range of about 6.6 to 7.6. This range provides an optimal environment for the biochemical processes that lead to the production of methane during anaerobic digestion. In this slightly acidic to neutral pH range, methanogens can effectively metabolize substrates such as organic matter and produce methane gas.

Operating within this pH range is crucial because both lower and higher pH levels can inhibit the activity of these microorganisms. For instance, very low pH values, such as those below 6.0, can be too acidic for the methanogens, leading to reduced activity and potentially causing process imbalances. Conversely, a higher pH, particularly above 7.6, may lead to the inhibition of methanogenic activity as well, since some species are sensitive to increased alkalinity.

Therefore, the choice indicating the pH range of 6.6 to 7.6 accurately reflects the conditions most conducive for methane production by fermentative bacteria in anaerobic digesters.