Description

The aim of this experiment is to characterize the conversion of nitrite to ammonium in wild type E. coli under anaerobic conditions.

The experiment was performed by adding three different concentrations of nitrite to a medium with a growing native strain of E. coli. The concentrations of ammonium (NH₄⁺) and nitrite (NO₂^-) were measured every 20 minutes and the experiment lasted for 3 hours. Also two controls: with biomass only (no nitrite) and without biomass were analyzed in order to exclude any external influences on the nitrite conversion.

Methods

Experimental protocol

Results

Mg of Nitrogen (as Nitrite or Ammonia) per litre measured for varying concentrations of Nitrite added at t=0. All experiments were performed anaerobically. Samples were measured every 20 min for 3 hours.

Conclusions and Discussion

Under anaerobic conditions, nitrite is consumed and converted to ammonium. Since we want to convert the nitrite to nitrous oxide, a functional prototype will require either that the pathway to nitrous oxide be designed to outcompete this pathway, or that this pathway that consumes nitrite be knocked out (and the transformants grown in a medium containing plentiful ammonium so they do not need to synthesize it).