This is necessary because microorganisms continues in their metabolism that will produce products that can cause changes in the pH of the culture. pH can be acidic or on the alkaline side. In the presence of buffers, the sudden change in pH will be prevented. This occurs when the pH is decreasing the salt in the weak base of the buffer will accept the excess hydrogen ions which result in formation weak acid. On the other hand, when the pH increases the weak acid will release the hydrogen ions which will form a weak base. Through this process the pH in the medium is well regulated.
