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Table 2 Thermotoga maritima cultures performed in bioreactor in the presence of different hydrogen partial pressures (pH2)

From: Hydrogen production by the hyperthermophilic bacterium Thermotoga maritima part I: effects of sulfured nutriments, with thiosulfate as model, on hydrogen production and growth

pH2 Time Cells Glu cons Lactate Acetate H2 CO2 Acet/glu Lac/glu Eh C-recovery
mbars h mg L−1 mmol L−1 mol mol−1 mV %
7.1 ± 0.4 t 0 0.0 14.8 ± 2.0 0.0 0.0 0.0 0.0 0.0 −130 ± 5
t 1 6.7 17.5 ± 3.2 0.3 ± 0.3 0.1 ± 0.1 0.6 ± 0.3 0.4 ± 0.0 0.4 ± 0.1 −135 ± 6
t 2 41.7 127.5 ± 9.7 18.5 ± 1.0 8.9 ± 1.0 23.6 ± 1.2 44.5 ± 3.3 22.5 ± 1.8 1.3 ± 0.1 0.5 ± 0.1 −314 ± 14 91.2 ± 15.1
t 3 49.8 122.5 ± 9.7 19.8 ± 1.1 10.5 ± 0.5 25.0 ± 1.4 46.4 ± 3.6 23.3 ± 1.9 1.3 ± 0.1 0.5 ± 0.0 −279 ± 30 92.1 ± 15.3
71.4 ± 2.1 t 0 0.0 14.7 ± 2.8 0.0 0.0 0.0 0.0 −152 ± 8
t 1 5.5 19.1 ± 2.7 0.5 ± 0.2 0.2 ± 0.1 0.7 ± 0.2 1.4 ± 0.6 0.3 ± 0.0 −151 ± 14
t 2 40.4 123.6 ± 9.6 18.1 ± 1.2 8.8 ± 0.6 22.5 ± 2.1 43.0 ± 4.4 20.0 ± 2.0 1.2 ± 0.1 0.5 ± 0.0 −409 ± 20 88.4 ± 14.7
t 3 46.2 118.2 ± 9.3 19.7 ± 1.4 11.0 ± 0.6 24.6 ± 2.4 48.0 ± 5.0 21.8 ± 2.2 1.2 ± 0.1 0.6 ± 0.0 −372 ± 19 91.6 ± 15.2
178.5 ± 3.5 t 0 0.0 12.7 ± 1.0 0.0 0.0 0.0 0.0 −161 ± 4
t 1 5.5 22.7 ± 1.7 0.2 ± 0.0 0.1 ± 0.1 0.2 ± 0.0 0.6 ± 0.0 0.3 ± 0.0 −176 ± 4
t2 38.2 129.8 ± 9.7 16.9 ± 0.8 9.2 ± 0.4 19.9 ± 1.0 39.3 ± 2.9 19.2 ± 1.5 1.2 ± 0.1 0.5 ± 0.0 −443 ± 11 90.1 ± 15.0
t 3 39.0 127.3 ± 9.6 17.2 ± 0.9 9.4 ± 0.5 20.1 ± 1.0 40.0 ± 3.0 19.5 ± 1.6 1.2 ± 0.1 0.5 ± 0.0 −426 ± 11 89.8 ± 14.9
606.9 ± 18.7 t 0 0.0 18.9 ± 1.4 0.0 0.0 0.0 a −239 ± 6
t 1 4.4 23.9 ± 1.8 1.0 ± 0.1 0.0 ± 0.0 0.0 ± 0.0 a 0.3 ± 0.0 −240 ± 6
t 2 41.7 96.4 ± 7.2 11.9 ± 0.6 8.9 ± 0.4 12.0 ± 0.6 a 11.1 ± 0.9 1.0 ± 0.1 0.7 ± 0.1 −449 ± 11 90.6 ± 15.0
t 3 48.5 96.3 ± 7.2 13.4 ± 0.7 11.0 ± 0.6 13.0 ± 0.7 a 12.2 ± 1.0 1.0 ± 0.1 0.8 ± 0.1 −440 ± 11 92.9 ± 15.4
  1. The culture medium contained initially 25 mmol L−1 of glucose and 1 g L−1 of yeast extract. Operating conditions for the regulations of pH, agitation, and temperature were adjusted to 7.0, 350 rpm, and 80 °C, respectively. The pH2, as reported in the table, were partial pressures of hydrogen maintained in the headspace of the bioreactor. 7.1, 71.4, 178.5, and 606.9 mbar were obtained with (H2/N2) gas mixtures: (1/99), (10/90), (25/75), and (85/15), respectively, and injected through the bioreactor at a constant total debit of 50 mL min−1 under a pressure close to 1 bar. Times t1 to t2, and t3 corresponded to the growth phases and to the end of the fermentation run, respectively
  2. a indicated that, under these experimental conditions [gas mixtures (H2/N2):(85/15)], biological productions of hydrogen could not be determined with sufficient precision
  3. Eh corresponds to the measurement, within the bioreactor, of the reduction potential relative to a standard hydrogen electrode. Carbon recovery was calculated as in the Table 1. All the batch cultures were performed in triplicate in bioreactor