Hg0 Hg2+ CH3Hg+ (CH3)2Hg

1
Microbial transformations of mercury in the
environment
lipophilic
CH3-
CH3-
2e-
Hg0 Hg2 CH3Hg (CH3)2Hg
HS-, -S-R
HgS, Hg-S-R
Algae
Fish
Children
Women
Infants
Fetus
2
Minnamata Bay
Hg2, Hg0
CH3-Hg, (CH3)2Hg
Anoxic sediment
Pathology constricted visual field, impairment
of vibration sense, total blindness, ataxia,
necrosis of Glia cells
3
Life is Redox Chemistry
AH2 B A BH2
DGlt0
Energy
DG -nFDE, DE Eacceptor - Edonor
4
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5
Carbon and electron flow in sulfidogenic
environments
Complex organic matter
Carbohydrates, nucleic acids proteins, lipids
1
Lactate Propionate Higher fatty
acids Alcohols Aromatic compounds
H2, CO2
Acetate
2
H2S, CO2
1
fermentative bacteria, e.g., lactic acid
bacteria, clostridia, enteric bacteria,
propionibacteria
2
sulfate-reducing bacteria, e.g., Desulfovibrio
spp, Desulfobacterium spp, Desulfobacter spp,
Desulfotomaculum spp.
6
Carbon and electron flow in methanogenic
environments
Complex organic matter
Carbohydrates, nucleic acids proteins, lipids
1
Lactate Propionate Higher fatty
acids Alcohols Aromatic compounds
2
H2, CO2
3
Acetate
4
CH4, CO2
1
fermentative bacteria, e.g., lactic acid
bacteria, clostridia, enteric bacteria,
propionibacteria
proton-reducing, syntrophic bacteria, e.g.,
Syntrophomonas spp, Syntrophobacter
2
3
homoacetogenic bacteria, e.g., Acetobacterium
woodii, Clostrodium aceticum
4
methanogenic archaea, e.g., Methanosarcina spp,
Methanobacterium spp., Methanospirillum spp.
7
Carbon and electron flow in sulfidogenic
environments
Complex organic matter
Carbohydrates, nucleic acids proteins, lipids
1
Lactate Propionate Higher fatty
acids Alcohols Aromatic compounds
H2, CO2
Acetate
2
H2S, CO2
1
fermentative bacteria, e.g., lactic acid
bacteria, clostridia, enteric bacteria,
propionibacteria
2
sulfate-reducing bacteria, e.g., Desulfovibrio
spp, Desulfobacterium spp, Desulfobacter spp,
Desulfotomaculum spp.
8
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9
Oxidative carbon monoxide pathway in
Sulfate-reducing bacteria
10
Mercury in the environment
lipophilic
CH3-
CH3-
2e-
Hg0 Hg2 CH3Hg (CH3)2Hg
HS-, -S-R
HgS, Hg-S-R
Algae
Fish
Children
Women
Infants
Fetus