| Küsel, K; Roth, U; Drake, HL: Microbial reduction of Fe(III) in the presence of oxygen under low pH conditions, Environmental Microbiology, 4(7), 414-421 (2002) | |
| Abstract: In acidic, coal mining lake sediments, facultatively anaerobic Acidiphilium species are likely involved in the reduction of Fe(III). Previous results indicate that these bacteria can co-respire O2 and Fe(III). In this study, we investigated the capacity of the sediment microbiota to reduce Fe(III) in the presence of O2 at pH 3. In sediment microcosms with 4% O2 in the headspace, the concentration of Fe(II) increased at a rate of 1.03 µmol (g wet sediment)-1 d-1 within the first 7 days of incubation which was similar to the rate obtained with controls incubated under anoxic conditions. However, in microcosms incubated under air, Fe(II) was consumed after a lag phase of 8 hours with a rate of 2.66 µmol (g wet sediment)-1 d-1. Acidiphilium cryptum JF-5, isolated from this sediment, reduced soluble Fe(III) with either 4 or 21% O2 in the headspace, and concomitantly consumed O2. However, the rate of Fe(II) formation normalized for cell density decreased under oxic conditions. Schwertmannite, the predominant Fe(III)-mineral of this sediment, was also reduced by A. cryptum JF-5 under oxic conditions. The rate of Fe(II) formation by A. cryptum JF-5 decreased after transfer from preincubation under air in medium lacking Fe(III). A. cryptum JF-5 did not form Fe(II) when preincubated under air and transferred to anoxic medium containing Fe(III) and chloramphenicol, an inhibitor of protein synthesis. These results indicate that (i) the reduction of Fe(III) can occur at low O2 concentrations in acidic sediments, (ii) Fe(II) can be oxidized at O2 concentrations near saturation, and (iii) the enzyme(s) responsible for the reduction of Fe(III) in A. cryptum JF-5 are not constitutive. |
Upcoming ...
Upcoming ...
| BayCEER Short Courses: |
|---|
| Fr. 2024-04-26 now Mobile Film Making Workshop (for students of BayCEER) |
| Ecological-Botanical Garden: |
| Su. 2024-04-28 Führung | Den Sängern auf der Spur: Vogelstimmen im ÖBG (zus. mit LBV) |
| Su. 2024-05-05 Führung | Faszination Englische Gärten: Gestaltung und Pflanzen |
| Su. 2024-05-05 Midissage | da capo - Ausstellung von Doris Bocka |
| We. 2024-05-15 Kurzführung | "Botanische Mittagspause" |