Identification and characterization of a denitrifying bacterium Pseudomonas fluorescens

Abstract:

[Objective] In order to isolate a bacterium, with high efficiency denitrifying, from activated sludge samples. [Methods] The strain, was named L2, isolated through domestication enrichment, purification, preliminary and secondary screening, which was identified based on its morphology characteristics, and 16S rRNA gene sequence analysis. we systematic studied its various denitrification characteristics as follows: inoculation volume, temperature, pH, salt concentration, carbon source, dissolved oxygen (DO), carbon nitrogen ratio (C/N) and initial nitrate concentration. [Results] The strain was identified as Pseudomonas fluorescens, and the results showed that the most suitable denitrification conditions of the strain are inoculation volume of 10%, temperature of 20 °C, with the poor thermal stability, pH of 7.0, salt concentration of 0.5%, carbon source of glucose, C/N of 5.0, and it can tolerate high initial nitrate concentration. [Conclusion] This Pseudomonas fluorescens, which had good resistance to low temperature, high tolerance to initial nitrate concentration, tolerance low carbon nitrogen ratio, was a facultative anaerobic efficient denitrifying bacterium.

Key words:Identification, Low-temperature, Denitrification, Pseudomonas fluorescens