TABLE 1.
16S rRNA gene copy numbers of specific bacterial groups enumerated by qPCRa
| Factor | Fermentation | Stabilization or treatment |
Days | Log10 16S rRNA gene copy no. of taxon ml−1 (mean ± SD): |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Firmicutes | Lactobacillus | Veillonella | Bacteroides | Bifidobacterium | Enterobacteriaceae | E. limosum | ||||
| Baseline in sample from | ||||||||||
| Fecal donorb | 1 | 9.88 | 9.10 | 9.35 | 9.34 | 9.24 | 9.39 | ND | ||
| Inoculum reactor | 1 | Stabilization | 21–23 | 10.01 ± 0.17 | 8.54 ± 0.34 | 8.81 ± 0.10 | 9.35 ± 0.14 | 9.45 ± 0.35 | 7.88 ± 0.17 | ND |
| Control reactor | 1 | Stabilization | 21–23 | 10.10 ± 0.10 | 8.22 ± 0.17 | 9.34 ± 0.30 | 9.45 ± 0.09 | 9.53 ± 0.26 | 8.58 ± 0.17 | ND |
| Fecal donorb | 2 | 9.68 | 6.00 | 8.64 | 9.46 | 7.56 | 7.85 | 2.68 | ||
| Inoculum reactor | 2 | Stabilization | 16–18 | 10.08 ± 0.14 | 6.71 ± 0.21 | 10.11 ± 0.31 | 9.58 ± 0.18 | 6.98 ± 0.30 | 8.01 ± 0.32 | ND |
| Control reactor | 2 | Stabilization | 16–18 | 10.28 ± 0.06 | 6.15 ± 0.10 | 10.88 ± 0.50 | 9.90 ± 0.05 | 7.13 ± 0.19 | 8.16 ± 0.08 | ND |
| pH | ||||||||||
| 6.0 | 1 | Stabilization | 21–23 | 10.05 ± 0.08 | 7.82 ± 0.29 | 8.76 ± 0.22 | 9.44 ± 0.17 | 9.53 ± 0.27 | 8.15 ± 0.23 | ND |
| 5.0 | 1 | Treatment | 29–31 | 9.38 ± 0.12** | 9.19 ± 0.08* | 7.52 ± 0.08* | 7.88 ± 0.10** | 9 ± 0.07 | 8.68 ± 0.23** | ND |
| 6.0 | 2 | Stabilization | 16–18 | 10.07 ± 0.16 | 6.19 ± 0.08 | 10.18 ± 0.16 | 9.58 ± 0.11 | 7.06 ± 0.25 | 7.87 ± 0.28 | ND |
| 5.0 | 2 | Treatment | 25–27 | 9.51 ± 0.03 | 7.85 ± 0.11** | 8.68 ± 0.24 | 8.24 ± 0.14 | 8.06 ± 0.07 | 7.67 ± 0.04 | ND |
| 6.0 | 1 | Stabilization | 21–23 | 10.00 ± 0.14 | 8.03 ± 0.32 | 9.49 ± 0.49 | 9.46 ± 0.28 | 9.51 ± 0.23 | 8.61 ± 0.31 | ND |
| 7.0 | 1 | Treatment | 29–31 | 9.77 ± 0.05* | 7.01 ± 0.11 | 9.35 ± 0.01 | 8.89 ± 0.03 | 8.32 ± 0.2* | 8.83 ± 0.03 | ND |
| 6.0 | 2 | Stabilization | 16–18 | 10.01 ± 0.28 | 6.21 ± 0.06 | 10.26 ± 0.27 | 9.57 ± 0.15 | 7.21 ± 0.36 | 8.12 ± 0.07 | ND |
| 7.0 | 2 | Treatment | 25–27 | 10.09 ± 0.03 | 6.12 ± 0.11 | 10.39 ± 0.14 | 9.61 ± 0.05 | 7.05 ± 0.08 | 8.64 ± 0.12* | ND |
| RT (h) | ||||||||||
| 5 | 1 | Stabilization | 21–23 | 10.08 ± 0.02 | 7.68 ± 0.17 | 9.00 ± 0.08 | 9.4 ± 0.06 | 9.49 ± 0.2 | 8.49 ± 0.2 | ND |
| 10 | 1 | Treatment | 29–31 | 9.51 ± 0.05** | 7.36 ± 0.32 | 8.47 ± 0.18* | 9.27 ± 0.08 | 8.66 ± 0.04* | 8.82 ± 0.19** | ND |
| 5 | 2 | Stabilization | 16–18 | 10.14 ± 0.13 | 6.16 ± 0.13 | 10.35 ± 0.33 | 9.65 ± 0.18 | 7.28 ± 0.26 | 8.18 ± 0.16 | ND |
| 10 | 2 | Treatment | 25–27 | 10.06 ± 0.12 | 6.32 ± 0.27 | 10.10 ± 0.21 | 9.52 ± 0.23 | 7.68 ± 0.36 | 8.17 ± 0.21 | ND |
| Supplemental lactate concn (mM) | ||||||||||
| 0 | 1 | Stabilization | 63–65 | 10.54 ± 0.26 | 8.94 ± 0.18 | 8.76 ± 0.17 | 9.85 ± 0.36 | 9.5 ± 0.07 | 8.22 ± 0.24 | 7.61 ± 0.35 |
| 60 | 1 | Treatment | 77–79 | 10.79 ± 0.26 | 8.13 ± 0.15* | 8.94 ± 0.18 | 10.4 ± 0.59 | 9.57 ± 0.18 | 8.04 ± 0.40 | 8.02 ± 0.06 |
| 0 | 2 | Stabilization | 38–40 | 10.28 ± 0.09 | 7.64 ± 0.06 | 10.21 ± 0.33 | 9.45 ± 0.13 | 6.95 ± 0.24 | 8.58 ± 0.04 | 2.63 ± 0.10 |
| 60 | 2 | Treatment | 49–51 | 10.06 ± 0.27 | 7.61 ± 0.24 | 10.06 ± 0.37 | 9.04 ± 0.25 | 6.74 ± 0.19 | 8.58 ± 0.33 | 2.54 ± 0.61 |
a
Data are means ± SD for the last 3 days of each stabilization and treatment; samples were analyzed in duplicate. Means with an asterisk (*) differ significantly between the previous stabilization and treatment within the same reactor within the same bacterial group: *, P < 0.05; **, P < 0.01; ND, not determined.
b
Data for fecal donor are expressed as log10 CFU g−1 feces.