TABLE 1.

Carbon balances of fructose (2.5 mM) and acetate during sulfate reduction and fermentation by Desulfovibrio fructosivorans in mixed cultures under the four different stable conditions

Conditiona	Carbon fluxes of fructose and acetate (mM)
	Fructose totally consumed	Fructose unused	Acetate totally detected	Fructoseb used for SRc	Acetateb produced by SRc	Fructoseb used for fermentation	Acetateb produced by fermentation	Acetate balance gapd
1	1.3	1.2	2.1	1.0	2.0	0.3	0.6	−0.5
2	2.4	0.1	4.4	2.4	4.8	0	0	−0.4
3	0.8	1.7	2.1	0	0	0.8	1.6	0.5
4	1.9	0.6	3.5	0	0	1.9	3.8	−0.3

^aThe different stable conditions are described in the text and in the legend of Fig. 1.

^bThe theoretical values of fructose used and acetate produced were calculated according to the following stoichiometric equations: C₆H₁₂O₆ + SO₄²⁻ → 2CH₃ − COO⁻ + 2HCO₃⁻ + HS⁻ + 3H⁺ for incomplete fructose oxidation during sulfate reduction (9) and C₆H₁₂O₆ + 4H₂O → 2CH₃ − COO⁻ + 2HCO₃₋ + 4H⁺+ 4H₂ for hexose fermentation (10).

^cSR, sulfate reduction.

^dThese values express the lacking acetate amounts likely used for biomass formation (except for condition 3, where the detected acetate concentration was too high).