. 2001 Feb;67(2):888–894. doi: 10.1128/AEM.67.2.888-894.2001

TABLE 3.

Free energy changes at standard state (ΔG^0′) and corresponding range of isotope fractionations (ɛ) during dissimilatory sulfate reduction with various electron donors for complete and incomplete oxidation

Electron donor (type of oxidation)	Stoichiometry	ΔG^0′ [kJ mol⁻¹ (SO₄)²⁻]^a	ɛ (‰)
Pyruvate (incomplete)	4 CH₃COCOO⁻ + 4 H₂O + SO₄²⁻ → 4 CH₃COO⁻ + 4 HCO₃⁻ + HS⁻ + 3 H⁺	−340.9	8.1
Lactate (incomplete)	2 CH₃CHOHCOO⁻ + SO₄²⁻ → 2 CH₃COO⁻ + 2 HCO₃⁻ + HS⁻ + H⁺	−160.1	2.0–17.0
Hydrogen	4 H₂ + SO₄²⁻ + H⁺ → 4 H₂O + HS⁻	−152.2	14.0
Formate	4 HCOO⁻ + SO₄²⁻ + H⁺ → 4 HCO₃⁻ + HS⁻	−146.9	5.5
Ethanol (incomplete)	2 CH₃CH₂OH + SO₄²⁻ → 2 CH₃COO⁻ + HS⁻ + 2 H₂O + H⁺	−146.6	18.7
Pyruvate (complete)	4 CH₃COCOO⁻ + 4 H₂O + 5 SO₄²⁻ → 12 HCO₃⁻ + 5 HS⁻ + 3 H⁺	−106.3	16.1; 25.7
Propionate (incomplete)	4 CH₃CH₂COO⁻ + 3 SO₄²⁻ → 4 CH₃COO⁻ + 4 HCO₃⁻ + 3 HS⁻ + H⁺	−50.2	5.5; 6.8
Benzoate (complete)	C₇H₅O₂⁻ + 3.75 SO₄²⁻ + 4 H₂O → 7 HCO₃⁻ + 3.75 HS⁻ + 2.25 H⁺	−49.7	15.0–42.0
Butyrate (complete)	CH₃CH₂CH₂COO⁻ + 2.5 SO₄²⁻ → 4 HCO₃⁻ + 2.5 HS⁻ + 0.5 H⁺	−49.2	23.1–32.7
Acetate (complete)	CH₃COO⁻ + SO₄²⁻ → 2HCO₃⁻ + HS⁻	−47.6	18.0–22.0

Calculated from the free energy change of formation using data from Hanselmann (19) and Thauer et al. (43).