Enhanced Alcaligenes faecalis Denitrification Rate with Electrodes as the Electron Donor.

Applied and environmental microbiology

PubMedID: 26048940

Wang X, Yu P, Zeng C, Ding H, Li Y, Wang C, Lu A. Enhanced Alcaligenes faecalis Denitrification Rate with Electrodes as the Electron Donor. Appl Environ Microbiol. 2015;.
The utilization by Alcaligenes faecalis of electrodes as the electron donor for denitrification was investigated in this study. The denitrification rate of A. faecalis with a poised potential was greatly enhanced compared with that of the controls without poised potentials. For nitrate reduction, although A. faecalis could not reduce nitrate, at three poised potentials of +0. 06, -0. 06, and -0. 15 V (versus normal hydrogen electrode [NHE]), the nitrate was partially reduced with -0. 15- and -0. 06-V potentials at rates of 17. 3 and 28. 5 mg/liter/day, respectively. The percentages of reduction for -0. 15 and -0. 06 V were 52. 4 and 30. 4%, respectively. Meanwhile, for nitrite reduction, the poised potentials greatly enhanced the nitrite reduction. The nitrite reduction rates for three poised potentials (-0. 06, -0. 15, and -0. 30 V) were 1. 98, 4. 37, and 3. 91 mg/liter/h, respectively. When the potentials were cut off, the nitrite reduction rate was maintained for 1. 5 h (from 2. 3 to 2. 25 mg/liter/h) and then greatly decreased, and the reduction rate (0. 38 mg/liter/h) was about 1/6 compared with the rate (2. 3 mg/liter/h) when potential was on. Then the potentials resumed, but the reduction rate did not resume and was only 2 times higher than the rate when the potential was off.