Isolation of chromium reducing bacteria for application in biological cathode of microbial fuel cell

Abstract:

[Objective] Water-soluble hexavalent chromium (Cr(VI)) environment and human hazards are the social problems to be solved urgently. Thus, the purpose of this study was to provide a scientific basis and a new method for Cr(VI) contaminated water bioremediation by the purification of Cr(VI) reduction strains and the application of the reduction properties in microbial fuel cells. [Methods] The samples were collected from the outfall of Lanzhou section of Yellow River. Then screened strains with Cr(VI) reduction ability by plate method and applied LZU-26 strain with the strongest Cr(VI) reducing ability to microbial fuel cells, measured the electricity generation capacity and Cr(VI) reduction characteristics. [Results] Strain LZU-26 can reduce 95.89% of Cr(VI) after 24 h and 99.97% after 48 h at initial Cr(VI) concentration of 0.4 mmol/L respectively. Furthermore, applying LZU-26 to microbial fuel cell biological cathode, we obtained the maximum voltage is 68 mV and the maximum power density is 6.8 W/cm2. And the Cr(VI) reduction rate of biological cathode (68.9%) was higher than that of chemical cathode (14.7%) and control group (2.7%). [Conclusion] Strain LZU-26 as a bio-cathode of MFCs will be an efficient, economical and environmentally friendly technology of chromium-containing wastewater treatment.

Key words:Cr(VI) reducing bacteria, MFC, Biological cathode, Chromium reduction rate