Skip to main content

Table 1 Comparison of growth parameters, electron uptake, metabolite concentrations and yields of heterotrophic anaerobic fermentations of C. autoethanogenum in a bio-electrochemical system in the presence and the absence of three different Co-mediators

From: Redox dependent metabolic shift in Clostridium autoethanogenum by extracellular electron supply

Condition Controla BESb BES + [Co(sep)]3+ BES + [Co(AMMEsar)]3+ BES + [Co(trans-diammac)]3+
Growth rate (h−1) 0.053 ± 0.006 0.053 ± 0.006 0.037 ± 0.006 0.033 ± 0.006 0.06 ± 0.017
OD600 max 1.51 ± 0.18 1.11 ± 0.03 1.30 ± 0.12 1.22 ± 0.22 1.09 ± 0.14
Current max (mA) 0.07 ± 0.03 1.34 ± 0.24 1.07 ± 0.19 1.18 ± 0.20
e uptake (mmol/L) 0.09 ± 0.01 2.77 ± 0.74 1.28 ± 0.16 2.51 ± 0.12
Final concentration (mmol/L)    
 Acetate 46.43 ± 5.24 42.36 ± 0.58 48.22 ± 0.21 40.9 ± 7.38 21.11 ± 0.96
 Lactate 0.28 ± 0.15 0.34 ± 0.04 0.34 ± 0.09 0.31 ± 0.11 9.87 ± 0.96
 Ethanol 17.63 ± 2.95 21.57 ± 0.54 13.83 ± 1.33 19.74 ± 0.61 19.04 ± 2.4
 2,3-BDO 0.73 ± 0.14 0.78 ± 0.05 0.48 ± 0.17 0.68 ± 0.19 2.21 ± 1.21
Yield (g/gfructose)     
 BM 7.6 ± 1.2 6.86 ± 0.38 6.3 ± 0.36 7.74 ± 1.51 6.66 ± 1.64
 Acetate 54.57 ± 4.31 50.51 ± 1.08 58.9 ± 0.36 52.06 ± 8.18 24.82 ± 2.35
 Lactate 0.52 ± 0.27 0.60 ± 0.05 0.56 ± 0.21 0.56 ± 0.18 18.32 ± 2.27
 Ethanol 12.76 ± 2.09 19.19 ± 0.23 10.89 ± 2.02 17.71 ± 2.28 15.69 ± 0.58
 2,3-BDO 1.31 ± 0.28 0.89 ± 0.04 0.69 ± 0.07 1.09 ± 0.52 4.02 ± 1.99
  1. Fermentation time = 100 h. All experiments were performed in biological triplicates
  2. aControl fermentations were performed in the same reactor set up with electrodes at open circuit
  3. bIn BES condition the working electrode was poised at −0.603 V (vs SHE) w/o mediator