MONITORING NITRIC-OXIDE FROM IMMOBILIZED DENITRIFYING BACTERIA, PSEUDOMONAS-STUTZERI, BY THE USE OF CHEMILUMINESCENCE

A chemiluminescence detector was used to measure the production of nit ric oxide, NO, from the denitrifying bacteria Pseudomonas stutzeri. NO is an intermediate when P. stutzeri converts nitrate into nitrogen ga s. The reaction between NO and ozone is selective and sensitive in gen erating chemiluminescence. Calibrations were made down to 1 nM, with a signal-to-noise ratio of 3. Bacteria were immobilised in alginate bea ds. Denitrification experiments were made in an anaerobic non-growth m edium by adding nitrate to a certain concentration in the reactor. The bacteria were exposed to nitrate in the concentration range 1 pM-5 mM . The lowest concentration to give a measurable NO response was 100 nM .