SUMMARY: Inhibition of autotrophic ammonia and nitrite oxidation by potassium ethyl xanthate (PEX) was studied in ammonium- and nitrite-limited chemostat cultures of and , respectively. Ammonia and nitrite oxidation were both stimulated by addition of low concentrations of PEX (0·1 μg ml), which significantly decreased steady-state substrate concentrations and increased steady-state cell concentrations. Addition of similar concentrations to exponentially growing cultures resulted in a slight stimulation of growth of but did not affect . Inhibition of ammonia and nitrite oxidation by higher concentrations of PEX resulted in establishment of steady states without induction of lag phases, observed in batch culture, which would have resulted in wash-out. Establishment of steady states occurred more quickly and with less variation in substrate concentrations following addition of inhibitory rather than stimulatory concentrations of PEX. Steady-state data indicate that PEX may act as a competitive inhibitor of nitrite oxidation by .


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error