Production and consumption of nitric oxide by denitrifying bacteria under anaerobic and aerobic conditions

Abstract

Pseudomonas aeruginosa, P. stutzeri and Azospirillum brasilense showed highest NO production rates and NO consumption rate constants when anaerobically grown cells were tested under anaerobic conditions. Aerobic assay conditions resulted in 20–75-fold lower NO production rates. NO consumption rate constants, however, decreased by less than a factor of four. NO consumption activity was observed even in aerobically grown P. aeruginosa , provided the assay was done under anaerobic conditions. Obviously, NO consumption was less O2-sensitive than NO production so that compensation between production and consumption occurred at lower NO mixing ratios under aerobic than under anaerobic conditions.