Abstract: A multi\|cathode bio\|electrode film reactor was used for nitrate removal from wastewater. The nitrate removal rate reached 1658 mg NO-3\|N·L-1·h-1 at the applied voltage of 0250 V. 16S rDNA was used to investigate the bacterial communities on the cathodes. The results indicated that the dominant bacteria were Proteobacteria， Bacteroidetes and Firmicutes. After applying a voltage of 0250 V， the bacteria communities were selected and enriched， especially Proteobacteria. Genus of Phyllobacterium and Caenispirillum from Proteobacteria may have great contribution to the enhancement of nitrate removal rate in the bio\|electron denitrification process under a low voltage.

Key words: bio\, electrode denitrification process, 16S rDNA, denitrification, bacterial diversity