TABLE 2.

Effect of pH and peptide input on final metabolite concentrations for fecal microbial communities in continuous culture

MetaboliteConcn (mM)a upon incubation at:
pH 6.5bpH 5.5cpH 6.5c (shifted from pH 5.5)Meand
Donor 1Donor 2Donor 1Donor 2Donor 1Donor 2pH 6.5pH 5.5
Medium + 0.6% peptide
    Formate0.50.50.30.10.30.30.40.2
    Acetate32.328.211.414.028.432.330.312.7
    Propionate20.118.310.15.123.220.620.67.6
    Butyrate4.35.826.323.56.34.95.324.9
    Valerate2.40.21.20.52.82.52.00.9
    Succinate1.31.900000.80
    dl-Lactate1.40.30000.40.50
    Ammonia7.74.32.31.50.91.03.51.9
Medium + 0.1% peptide
    Formate7.80.30.35.66.40.63.83.0
    Acetate26.433.342.234.145.332.134.338.2
    Propionate12.06.14.20.96.65.67.62.6
    Butyrate7.35.216.111.45.312.77.613.8
    Valerate1.20.10.50.50.50.90.70.5
    Succinate04.703.61.72.52.21.8
    dl-Lactate3.72.701.21.90.62.20.6
    Ammonia0.070.090.20.030.080.020.070.12
  • a Means of three determinations are shown; typical errors can be seen from Fig. 1 and 2.

  • b From the experiment shown in Fig. 1 (but including data for donor 1). Data refer to the final (192-h) time point.

  • c From the experiment shown in Fig. 2 (but including data for the low-peptide condition). Data refer to the final time point at the relevant pH (donor 1, 144 h, pH 5.5, and 360 h, pH 6.5; donor 2, 216 h, pH 5.5, and 458 h, pH 6.5).

  • d Overall means of preceding four values at pH 6.5, two at 5.5; the statistical analysis (analysis of variance) is described in the text.