For the pH adjustment study, HCl was used to lower the pH to 3 or 4; NaOH was used for
all other adjustments. Media was aliquoted at 125 ml in 250 ml Erlenmeyer flasks, the opening was covered by silicone sponge filters(Chemglass, Vineland, NJ), and steam sterilized for 45 min at 121 °C.
The growth cycle for each experiment was two weeks and cultures
were shaken on rotary platforms as above