Dynamic behavior in response to pH shift during anaerobic acidogenesis with a chemostat culture

To clarify the dynamic behavior of the anaerobic acid reactor in response t o pH changes, a continuous cultivation was performed. By stepwise shifting the culture pH in the acid reactor from 6.0 to 8.0, the main products were changed from butyric acid to acetic and propionic acids. This phenomenon wa s reproducible, reversible and was not affected by the dilution rate. It wa s considered that the dominant microbial populations changed in the acid re actor due to the pH shift.