TABLE 7.
Fermentation parameters for consecutive batch culture 4 (CBC4; Experiment 2).
|
Time point (hours) |
P-value |
||||||
| Inoculum | 24 | 48 | SEM | Time | Inoculum | Time*Inoculum1 | |
| Gas volume (ml) | G | 157.0 | 241.0 | 28.01 | <0.001 | 0.642 | (0.531) |
| B | 157.8 | 233.0 | |||||
| M | 157.0 | 239.2 | |||||
| pH | Ga | 6.51 | 6.48 | 3.07 x 10–5 | <0.001 | 0.031 | (0.274) |
| Bac | 6.51 | 6.48 | |||||
| Mbc | 6.49 | 6.48 | |||||
| NH3-N (mg/ml) | G | 1.26 | 1.66 | 0.006 | <0.001 | 0.893 | (0.184) |
| B | 1.39 | 1.58 | |||||
| M | 1.35 | 1.63 | |||||
| MCP (μg/ml) | G | 175.0 | 312.6 | 36.20 | <0.001 | 0.288 | (0.472) |
| B | 201.2 | 431.6 | |||||
| M | 208.7 | 335.6 | |||||
| tVFA (mM) | G | 73.8 | 101.1 | 3.20 | <0.001 | 0.650 | (0.455) |
| B | 73.6 | 103.3 | |||||
| M | 75.6 | 101.7 | |||||
| Acetate (mM) | G | 40.2 | 57.6 | 0.39 | <0.001 | 0.064 | (0.633) |
| B | 40.2 | 59.5 | |||||
| M | 42.3 | 60.3 | |||||
| Propionate (mM) | Ga | 23.9 | 30.7 | 0.19 | <0.001 | 0.002 | (0.171) |
| Bb | 25.0 | 32.6 | |||||
| Mb | 26.3 | 32.2 | |||||
| Butyrate (mM) | Ga | 9.8 | 12.8 | 0.10 | <0.001 | <0.001 | (0.403) |
| Bb | 8.4 | 11.2 | |||||
| Mc | 6.9 | 9.2 | |||||
With the exception of pH, mean values shown are normalized for substrate DM (1 g) added to the model. G, Good; B, Bad; M, Mix; SEM, standard error of the mean; NH3-N, ammonia-nitrogen; MCP, microbial crude protein; tVFA, total volatile fatty acids. 1Where an interaction was not significant (P-values shown in brackets) in the model, it was removed from the analysis and the model was re-run. a–cInocula that do not share a common superscript are significantly different (p < 0.05).