Sodium sulphate and sodium chloride effects on batch culture of iron oxidising bacteria

The effect of specific inhibitors on the growth and activity of chemolithotrophic cells has been studied by a number of workers using a comparative batch culture technique. In this study, the comparison method has been quantified and the test period extended to provide information about the ability of mixed cultures to adapt or become habituated to elevated concentrations of sodium sulphate and sodium chloride. oxidation culture showed the ability to rapidly adapt to concentrations of sodium sulphate up to 20 g L− 1 within 20–30 generations. Higher concentrations of 40 g L− 1 imposed a permanent inhibitive effect that reduced the maximum cell reproduction rate by ca. 50%. Since sulphate is rarely present in process water at these concentrations, this electrolyte does not present significant problems to operational processes. o-oxidation culture proved capable of adapting only to low concentrations of sodium chloride. Concentrations of 7 g L− 1 or greater provoked an inhibitive effect that reduced the cell replication rate by more than 50%. Prolonged exposure to sodium chloride at these concentrations demonstrated that no significant culture adaptation or habituation occurred.