Abstract: In order to research the mechanism of nitrate-contaminated groundwater bioremediation, a heterotrophic denitrifier was isolated and identified from the reed-wetland in Chaohu lake, and its denitrification activity was studied. Denitrifer was isolated on sodium potassium tartrate agar, and 16S rDNA identification and phylogenetic analysis of the strain were performed. The influence of solo carbon source and C/N ratio on the denitrification activity was studied and the suitability of the strain for nitrate content in water was researched. A heterotrophic denitrifier with high denitrification activity was isolated and named DB-1. The isolated strain was gram negative, a facultative anaerobe, and a micrococcus bacterium. The 16S rDNA sequence analysis revealed that strain DB-1 had a similarity of 996% to Klebsiella sp. When sodium acetate was used as carbon source, NO-3-N could be removed almost completely from water at 120 h while keeping C/N ratio of 3 and the initial nitrate concentration was 100 mg/L. The strain DB-1 was a heterotrophic denitrifier, with extensive carbon source scope and capable of removing nitrate effectively from water.

Key words: heterotrophic denitrifier, 16S rDNA sequence identification, activity research