Anaerobic and aerobic oxidation of ferrous iron at neutral pH by chemoheterotrophic nitrate-reducing bacteria |
| |
Authors: | M Benz Andreas Brune Bernhard Schink |
| |
Institution: | Fakult?t für Biologie, Universit?t Konstanz, Postfach 5560, D-78434 Konstanz, Germany Tel. +49-7531-883249; Fax +49-7531-882966 e-mail: marcus.benz@uni-konstanz.de, DE
|
| |
Abstract: | Nine out of ten anaerobic enrichment cultures inoculated with sediment samples from various freshwater, brackish-water, and
marine sediments exhibited ferrous iron oxidation in mineral media with nitrate and an organic cosubstrate at pH 7.2 and 30° C.
Anaerobic nitrate-dependent ferrous iron oxidation was a biological process. One strain isolated from brackish-water sediment
(strain HidR2, a motile, nonsporeforming, gram-negative rod) was chosen for further investigation of ferrous iron oxidation
in the presence of acetate as cosubstrate. Strain HidR2 oxidized between 0.7 and 4.9 mM ferrous iron aerobically and anaerobically
at pH 7.2 and 30° C in the presence of small amounts of acetate (between 0.2 and 1.1 mM). The strain gained energy for growth
from anaerobic ferrous iron oxidation with nitrate, and the ratio of iron oxidized to acetate provided was constant at limiting
acetate supply. The ability to oxidize ferrous iron anaerobically with nitrate at approximately pH 7 appears to be a widespread
capacity among mesophilic denitrifying bacteria. Since nitrate-dependent iron oxidation closes the iron cycle within the anoxic
zone of sediments and aerobic iron oxidation enhances the reoxidation of ferrous to ferric iron in the oxic zone, both processes
increase the importance of iron as a transient electron carrier in the turnover of organic matter in natural sediments.
Received: 24 April 1997 / Accepted: 22 September 1997 |
| |
Keywords: | Iron oxidation Ferrous iron Ferric iron Nitrate reduction Sediments |
本文献已被 SpringerLink 等数据库收录! |
|