TABLE 4

Metabolite profiles of E. faecalis strains cultured under each conditiona

StrainCarbon sourceO2Concn of consumed carbon source (mM)Metabolite concn (mM)Carbon balance (%)b
AALAcetateAcetoinEthanolFormated-Lactatel-Lactate
W11Glucose+50<0.135.119.1<0.10.20.118.592
50<0.1<0.10.36.211.70.178.888
Δpfl mutantGlucose+50<0.137.115.6<0.10.20.136.9105
50<0.10.90.2<0.10.20.190.192
W11Glycerol+100<0.155.012.9<0.10.10.27.789
100<0.1<0.10.361.362.10.233.896
Δpfl mutantGlycerol+100<0.175.213.01.1<0.10.16.6109
36<0.12.60.25.40.20.234.3119
W11DHA+100<0.179.84.3<0.11.41.60.390
100<0.124.30.510.726.71.645.683
Δpfl mutantDHA+100<0.178.51.9<0.1<0.11.33.687
100<0.117.80.211.60.11.258.890
  • a E. faecalis strains were cultured in M-MRS broth containing 50 mM glucose, 100 mM glycerol, or 100 mM DHA for 36 h under aerobic (+) and anaerobic (−) conditions. M-MRS broth contains 36 mM acetate, 0.5 mM ethanol, 0.1 mM formate, 0.3 mM d-lactate, and 11.1 mM l-lactate; metabolite concentrations are presented exclusive of these initial amounts. The results are the means of results from three experiments. The standard errors were all <10%. AAL, acetaldehyde.

  • b The concentrations of CO2 (mM) generated by the Pdh and AlsS reactions were calculated as follows. CO2 (Pdh) = (AAL [mM] + acetate [mM] + ethanol [mM]) − formate (mM). CO2 (AlsS) = acetoin (mM).