Enzymatic versus nonenzymatic conversions during the reduction of EDTA-chelated Fe(III) in BioDeNOx reactors.
Reduction of EDTA-chelated Fe(III) is one of the core processes in the BioDeNOx process, a chemically enhanced technique for biological NOx removal from industrial flue gases. The capacity of Escherichia coli, three mixed cultures from full scale methanogenic granular sludge reactors, one denitrifying sludge, and a BioDeNOx sludge to reduce Fe(III)EDTA- (25 mM) was determined at 37 and 55 degrees C using batch experiments. Addition of catalytic amounts of sulfide greatly accelerated Fe(III)EDTA- reduction, indicating that biological Fe(III)EDTA- reduction is not a direct, enzymatic conversion but an indirect reduction with involvement of an electron-mediating compound, presumably polysulfides. It is suggested that not thermophilic dissimilatory iron-reducing bacteria but reducers of elemental sulfur or polysulfides are primarily involved in the reduction of EDTA-chelated Fe(III) in BioDeNOx reactors.
Van Der Maas
Peter
P
Sub-Department of Environmental Technology, Wageningen University, Bomenweg 2, 6700 EV Wageningen, The Netherlands.
Peng
Shen
S
Klapwijk
Bram
B
Lens
Piet
P
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002384:Catalysis; D004492:Edetic Acid / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005290:Ferric Compounds / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005740:Gases / Q000737:chemistry; D007220:Industrial Waste; D008697:Methane / Q000378:metabolism; D009569:Nitric Oxide / Q000302:isolation & purification*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013440:Sulfides / Q000494:pharmacology; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism
D005290:Ferric Compounds; D005740:Gases; D007220:Industrial Waste; D012722:Sewage; D013440:Sulfides; D014874:Water Pollutants, Chemical; D009569:Nitric Oxide; D004492:Edetic Acid; C019179:Fe(III)-EDTA; D008697:Methane