Transcript Iron-Reducing Bacteria Hopkins Microbiology Course Presented by Ying Lei 22 July 2010 Reduction Process 1.

Iron-Reducing Bacteria
Hopkins Microbiology Course
Presented by Ying Lei
22 July 2010
Reduction Process
1. Fe3+ only
– ferrihydrite (FeOOH · 0.4H2O)
– orange/red solid
2. Fe3+/Fe2+
– magnetite (Fe3O4)
– black, ferromagnetic solid
3. Fe2+ only
– ferrous iron
– black, non-magnetic solid
Redox Tower
Reduced Species
Oxidized Species
Redox Potential (E0’)
[CH2O]
CO2
-470 mV
Fe2+
αFe2O3
-280 mV
Fe2+
αFeOOH
-280 mV
CH4
CO2
-250 mV
H2S
SO42-
-220 mV
Fe2+
γFeOOH
-100 mV
Fe2+
Fe(OH)3
0 mV
Fe2+
Fe3+
+770 mV
H2O
O2
+820 mV
CH3CH(OH)COO- + 12 FeOOH + 4 H2O  3 HCO3- + 12 Fe2+ + 22 OHlactate
C0
iron (III)
Fe3+
CO2
C4+
iron (II)
Fe2+
Canfield et al, Aquatic Geomicrobiology (2005)
Enrichment Medium
Component
Amount
Purpose
basal marine mineral medium
1L
basic salts
sodium lactate
4.5 g (30 mM)
carbon source
NaHCO3
30 mL (30 mM)
pH buffer
iron (III) hydroxide
30 mL (40 mM)
ferric iron source
7-vitamin solution
30 mL
cofactors
SL 10
1 mL
trace elements
Se-Wo solution
1 mL
trace elements
Adjust to pH 7.2 in Pfennig bottles and incubate under anoxic conditions.
Hopkins Microbiology Course (2010)
Sample Collection
Canfield et al, Aquatic Geomicrobiology (2005)
Sample Collection
Successful Enrichments
Marcus
Thank You
All Instructors and Students
Chris
Marcus
Blanca
Additional Slides
Iron Solubility
OzCoasts (www.ozcoasts.org.au)