COMPARISON OF DENITRIFICATION BY PARACOCCUS-DENITRIFICANS, PSEUDOMONAS-STUTZERI AND PSEUDOMONAS-AERUGINOSA

The course of denitrification of nitrate, nitrite and both compounds t ogether by static cultures of Paracoccus denitrificans, Pseudomonas st utzeri and Pseudomonas aeruginosa was studied. These strains represent three different types of denitrification: 1. reduction of nitrate to gaseous nitrogen without accumulation of nitrite (P. denitrificans); 2 . partial accumulation of nitrite in growing cultures during reduction of nitrate to gaseous nitrogen (P. aeruginosa) and 3. two-phase denit rification that includes reduction of nitrates at the very begining of the process, and then, after depletion of the former, the reduction o f nitrates to gaseous nitrogen (P. stutzeri). These observations diffe r from the results reported in the literature and possible reasons are discussed.