[Microbial reduction of Fe(III) (EDTA) in the system of nitric oxide removal by metal chelate absorption].

Reduction of Fe(III) (EDTA) with cultivated microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Supplemental glucose stimulates the formation of Fe(II) (EDTA) more than ethanol and methanol as the carbon sources. Ammonium salt was used to be as the nitric source instead of nitrate, which inhibits the reduction of Fe(III) (EDTA) due to the competition between the two electron acceptors. The optimal pH value was from 6 to 7. The reduction percentage of Fe(III) (EDTA) varied little with the range of 30 degrees C - 40 degrees C and decreased quickly with a temperature higher than 40 degrees C. The bio-reduction could be achieved efficiently with enough carbon source and cell inoculation. The reduction rate did not increase with adding more amount of carbon source or cell inoculation. The bio-reduction rate could be described by Michaelis-Menten equation and fitted to the first order reaction kinetics. The maximum reaction rates gamma max and the Michaelis constant k(m) were 1.3 mmol x (L x h)(-1) and 53.5 mmol x L(-1)respectively.