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Table 1 pH-controlled batch fermentations of C. celer on 5 g/l of glucose at different culture pH

From: Assessment of metabolic flux distribution in the thermophilic hydrogen producer Caloramator celer as affected by external pH and hydrogen partial pressure

   pH  
  8 7 6 5.5
μ max (h-1) 1.50 ± 0.05 1.34 ± 0.05 0.53 ± 0.01 0.45 ± 0.06
Biomass concentration (gCDW/l) 0.95 ± 0.01 0.95 ± 0.06 0.76 ± 0.01 0.42 ± 0.01
q glucose a (mmol/gCDW/h) 19.6 ± 1.4 20.6 ± 0.1 14.3 ± 0.1 14.0 ± 0.2
YX/ATP (gCDW/mol ATP) 15.4 ± 0.7 15.2 ± 0.4 6.8 ± 0.2 6.0 ± 0.4
YATP/S (mol ATP/mol glucose) 2.81 ± 0.02 3.05 ± 0.03 3.54 ± 0.33 3.60 ± 0.09
H2 accumulation (mmol H2/l) 68.0 ± 1.3 64.2 ± 1.1 106.0 ± 2.3 91.7 ± 0.4
Q H2 (mmol H2/l/h) 25.2 ± 1.2 21.0 ± 1.3 14.9 ± 0.2 13.0 ± 0.9
Product yield (mol/mol glucose)     
  YX b 1.29 ± 0.05 1.37 ± 0.07 1.04 ± 0.01 0.62 ± 0.02
  YH2 b 1.90 ± 0.01 1.69 ± 0.03 2.97 ± 0.10 2.48 ± 0.03
  YA b 1.04 ± 0.01 1.02 ± 0.04 1.33 ± 0.08 1.28 ± 0.04
  YF b 0.45 ± 0.01 0.37 ± 0.11 0.14 ± 0.02 0.19 ± 0.01
  YE b 0.35 ± 0.01 0.48 ± 0.05 0.20 ± 0.01 0.36 ± 0.03
RVEP c 2.60 ± 0.03 2.65 ± 0.13 3.36 ± 0.09 3.19 ± 0.02
HAc/EtOH 2.96 ± 0.11 2.15 ± 0.30 6.83 ± 0.67 3.60 ± 0.14
Carbon recovery (%) 88.6 ± 1.1 99.8 ± 1.5 100.7 ± 2.8 93.5 ± 1.6
Redox recovery (%) 94.4 ± 0.6 99.2 ± 0.7 98.4 ± 3.2 93.6 ± 2.1
  1. aSpecific glucose consumption rate measured during exponential phase.
  2. bY indicates the yield of product (where x=biomass, H2=hydrogen, A=acetate, F=formate and E=ethanol) per mole of glucose consumed.
  3. cTotal molar reduction values of reduced end-products (RVEP = YH2 + 2 * YE) [19].