Table 2.

Calculated Gibbs` free energy for conversion of glucose to pyruvate and lactate to pyruvate.

Reaction	ΔG 0
Equation 1: Glucose + 2Pi + 2ADP + 2NAD+ → 2 Pyruvate + 2ATP + 2NADH + 2H+ + 2H2O	−88 kJ/mol
Equation 2a: Lactate + NAD+ ↔ Pyruvate + NADH	+25 kJ/mol
Equation 2b as proposed by Weghoff et al. (2015): Lactate + Fd2− + 2NAD+ → Pyruvate + Fd + 2NADH	−9.5 kJ/mol
Equation 3: 4 Lactate + 2 Acetate → 3 Butyrate + 4CO2 + 2H2 + 2H2O	−139 kJ/mol
Equation 4: Glucose + 2H2O → Butyrate + 2CO2 + 4H2	−249.96 kJ/mol

The calculations were done following the information reported previously (Thauer et al., 1977).