Table 4. Molar proportion of volatile fatty acids (VFA) in cultures

Incubation times (h) SEM Contrast
24 48 72 Linear Quadratic
Total VFA (mM)
 Ec 33.5a 45.9b 70.9a 5.54 < 0.001 0.008
 AAFB 23.1b 28.0c 32.3b 1.40 < 0.001 NS
 Ec + AAFB 33.9a 59.2a 75.8a 6.15 < 0.001 NS
VFA (moL/100 moL)
 Acetate
  Ec 76.3a 67.0b 53.8b 3.28 < 0.001 0.002
  AAFB 76.5a 73.5a 72.7a 0.60 < 0.001 0.011
  Ec + AAFB 72.5b 53.8c 46.8c 3.84 < 0.001 < 0.001
 Propionate
 Ec 15.2b 24.1b 37.8b 3.30 < 0.001 0.0115
 AAFB 12.10c 16.1c 15.3c 0.61 < 0.001 < 0.0001
 Ec + AAFB 17.1a 37.2a 43.4a 3.98 < 0.001 < 0.0001
 Butyrate
  Ec 6.61c 7.29b 6.74c 0.15 NS NS
  AAFB 8.75a 8.00a 9.24a 0.19 0.006 < 0.001
  Ec + AAFB 8.24b 7.34b 7.79b 0.14 0.021 0.002
 Valerate
  Ec 0.66b 0.49b 0.35b 0.05 < 0.001 NS
  AAFB 1.00a 0.84a 0.76a 0.04 < 0.001 NS
  Ec + AAFB 0.67b 0.44c 0.37b 0.05 < 0.001 < 0.001
 Total BCVFA
  Ec 1.21b 1.15b 1.36 0.06 NS NS
  AAFB 1.61a 1.54a 1.97 0.09 NS NS
  Ec + AAFB 1.51a 1.27ab 1.64 0.07 NS 0.017
 Acetate:Propionate ratio
  Ec 5.03b 2.79b 1.43b 0.53 < 0.001 < 0.001
  AAFB 6.33a 4.57a 4.74a 0.28 < 0.001 < 0.001
  Ec + AAFB 4.25c 1.45c 1.08c 0.50 < 0.001 < 0.001
Means within a row with different superscripts differ (p < 0.05).
Ec, Entodinium caudatum alone; AAFB, amino acid-fermenting bacterial consortium alone; NS, not significant (p > 0.05); Ec + AAFB, co-culture of both Ec and AAFB; BCVFA, branched-chain VFAs.