TABLE 2 .

Electron balances based on each metabolite’s electron equivalence^b

Substrate, product, or parameter	Mean ± SD for culture with pH on substratec
	pH 6.0			pH 6.5			pH 6.9
	Glu	Fru	Cello	Glu	Fru	Cello	Glu	Fru	Cello
Substrate	13.29 ± 0.9	13.59 ± 0.7	26.18 ± 3.5	13.10 ± 1.7	11.94 ± 0.9	24.31 ± 1.3	12.21 ± 0.5	11.83 ± 0.4	19.95 ± 1.1
Products
Lactate	7.37 ± 1.3	8.24 ± 0.7	7.46 ± 0.9	0.00 ± 0.0	0.08 ± 0.1	1.61 ± 0.3	0.00 ± 0.0	0.00 ± 0.0	0.01 ± 0.0
Acetate	1.14 ± 0.2	1.10 ± 0.1	0.98 ± 0.1	2.80 ± 0.3	2.94 ± 0.2	2.14 ± 1.2	3.09 ± 0.2	3.27 ± 0.1	5.08 ± 0.2
Propionate	0.24 ± 0.0	0.28 ± 0.1	0.29 ± 0.1	4.32 ± 0.7	4.39 ± 0.5	2.40 ± 3.6	4.10 ± 0.5	4.26 ± 0.1	7.60 ± 0.2
Butyrate	0.48 ± 0.0	0.50 ± 0.1	0.43 ± 0.0	0.53 ± 0.1	0.60 ± 0.0	0.52 ± 0.1	0.61 ± 0.0	0.61 ± 0.0	0.75 ± 0.0
Formate	0.02 ± 0.0	0.10 ± 0.0	0.18 ± 0.0	0.03 ± 0.1	0.01 ± 0.0	0.10 ± 0.1	0.06 ± 0.0	0.01 ± 0.0	0.00 ± 0.0
Isobutyrate	0.03 ± 0.0	0.05 ± 0.0	0.03 ± 0.0	0.61 ± 0.9	0.18 ± 0.2	0.98 ± 0.4	0.10 ± 0.0	0.08 ± 0.0	0.12 ± 0.0
Valerate	0.08 ± 0.0	0.16 ± 0.0	0.22 ± 0.1	0.10 ± 0.0	0.18 ± 0.0	0.16 ± 0.1	0.20 ± 0.1	0.20 ± 0.0	0.16 ± 0.1
Isovalerate	0.04 ± 0.0	0.09 ± 0.0	0.25 ± 0.2	0.00 ± 0.0	0.06 ± 0.0	0.43 ± 0.3	0.00 ± 0.0	0.12 ± 0.1	0.09 ± 0.0
Citrate	0.40 ± 0.3	0.64 ± 0.4	1.42 ± 0.5	0.00 ± 0.0	0.02 ± 0.0	2.97 ± 1.9	0.00 ± 0.0	0.00 ± 0.0	0.01 ± 0.0
Hydrogen	0.08 ± 0.0	0.15 ± 0.0	0.02 ± 0.0	0.29 ± 0.0	0.15 ± 0.0	0.28 ± 0.4	0.13 ± 0.0	0.04 ± 0.0	0.04 ± 0.0
Ethanol	0.21 ± 0.0	0.21 ± 0.0	0.29 ± 0.0	0.68 ± 0.2	0.62 ± 0.0	0.67 ± 0.2	0.77 ± 0.2	0.69 ± 0.1	1.34 ± 0.1
Biomass	0.89 ± 0.1	0.76 ± 0.2	1.15 ± 0.3	1.22 ± 0.3	1.09 ± 0.2	1.86 ± 0.6	0.74 ± 0.3	1.07 ± 0.1	1.55 ± 0.7
RSa	0.00 ± 0.0	0.00 ± 0.0	13.21 ± 3.7	0.00 ± 0.0	0.00 ± 0.0	5.36 ± 4.6	0.00 ± 0.0	0.00 ± 0.0	0.00 ± 0.0
Total	10.76 ± 1.1	12.06 ± 0.9	25.63 ± 3.4	9.91 ± 0.9	9.69 ± 0.5	18.82 ± 1.0	8.65 ± 0.6	9.67 ± 0.43	15.42 ± 0.6
% recovery	80.90 ± 4.42	88.78 ± 5.2	97.96 ± 0.7	75.85 ± 3.2	81.22 ± 1.6	77.41 ± 0.7	73.12 ± 6.1	81.69 ± 3.07	77.38 ± 4.2

^aRS, remaining substrate at end of experiment.

^bElectrons for the biomass were determined based on the measured chemical oxygen demand. % recovery was calculated based on how much of the initial electron equivalents could be tracked by measurements at the end of the experiment.

^cGlu, Fru, and Cello indicate that the initial substrate was glucose, fructose, or cellobiose, respectively. All concentrations and electron equivalents are those measured at the end of the experiment.