Novel denitrifying bacteria Pseudomonas stutzeri strain D1 - from isolation to the biomass production

An aerobic denitrifier was newly isolated and identified by VITEK? 2 Compact System and MALDI-TOF MS as P. stutzeri strain D1. Sequence amplification indicates that the denitrification genes napA, nirS, norB and nosZ are present in a novel strain D1, as well as in reference strain ATCC 17588. Strain D1 had capability to fully remove 3 g/L of nitrate (as KNO3) in 48 h, while the reference strain completed this task in 60 h. Single factor experiments indicate that the optimal conditions for biomass production were: temperature of 30?C, pH value of 7 and inoculum volume of 5 vol.%. Scaling up of biomass production of both denitrifiers was successfully performed in 3 and 7 L laboratory bioreactors by reaching 9 log CFU/mL of the viable cells. The results demonstrate the feasibility of using investigated P. stutzeri strains in denitrification processes and the simplicity of the up-scaling of biomass production for the treatment of large areas contaminated with nitrate.