The removal of nitrogen compounds from a wastewater is essential and it is often accomplished by biological process. An aerobic nitrate-removing bacterium was isolated from a municipal sewage treatment plant and soil. On the basis of its morphological, cultural and physiological characteristics and 16S rRNA sequencing data, this strain was identified as Pseudomonas fluorescens, and named as P. fluorescens K4. The optimal conditions of the initial pH and temperature of media for its growth were 7.0~8.0 and 30℃, respectively. P. fluorescens K4 was able to remove 99.9% of nitrate after 24 h in a culture. The strain could grow with a nitrate concentration up to 800 mg/l and was able to remove 99.9% of nitrate after 104 h of incubation. The optimal electron donor was sodium citrate for a nitrate removal. The strain K4 showed a capability of a complete nitrate removal when the initial C/N ratio was 1.0. An effect of the initial seed concentration was observed for a cell of 10% (v/v) for a nitrate removal. Especially P. fluorescens K4 could completely remove 200 mg/l ammonium for 3 days.

• O Mi Lee(Korea Atomic Energy Research Institute)
• Jong Hyeok Oh(Korea Research Institute of Chemical Industry)
• Doo Seong Hwang(Korea Atomic Energy Research Institute)
• Yun Dong Choi(Korea Atomic Energy Research Institute)
• Un Soo Chung(Korea Atomic Energy Research Institute)
• Jin Ho Park(Korea Atomic Energy Research Institute)
• Min Ju Kim(Department of Microbiology, Pusan National University)
• Seong Yun Jeong(Korea Bio-IT Foundry Center, Pusan National University)
• Sang Joon Lee(Department of Microbiology, Pusan National University) Corresponding Author