Reduction of Fe(III)EDTA by Klebsiella sp strain FD-3 in NOx scrubber solutions

Biological reduction of Fe(III) to Fe(II) is a key step in nitrogen oxides (NOx) removal by the integrated chemical absorption-biological reduction method, which determines the concentration of Fe(II) in the scrubbing liquid. A new Fe(III)EDTA reduction strain, named as FD-3, was isolated from mixed cultures used in the integrated NOx removal process and identified as Klebsiella sp. by 16S rDNA sequence analysis. The reduction abilities of FD-3 and the influence of nitrogen-containing compounds (Fe(II)EDTA-NO, NO; and NOD and sulfur-containing compounds (SO42-, SO32-) on the Fe(III)EDTA reduction were investigated. The results indicated that strain FD-3 could reduce Fe(III)EDTA efficiently. NO3-, NO2- and Fe(II)EDTA-NO inhibit the reduction of Fe(III)EDTA and could also serve as electron acceptor for strain FD-3. SO32- inhibited Fe(III)EDTA reduction while SO42- had no obviously effect on Fe(III)EDTA reduction. The relationship between cell growth and Fe(III)EDTA reduction could be described by the models based on Logistic equation. (C) 2013 Elsevier Ltd. All rights reserved.