Table 3 Fermentation results for coffee silverskin hydrolysates with four different bacterial strains at two levels of yeast extract concentration
Strain | Yeast extract (g/L) | Sample | Bacterial growth | ABE fermentation metabolites | Sugar consumption | Yield and productivity | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Density (cell/mL) | Acetone (g/L) | Butanol (g/L) | Ethanol (g/L) | Acetic acid (g/L) | Butyric acid (g/L) | Isopropanol (g/L) | Total sugars (%) | Y B/S (g/g) | WB (g/L·h) | |||
CECT 508 | 1 | Control | 3.5·108 | 2.15 ± 0.66 | 6.55 ± 0.43 | 0.10 ± 0.02 | 0.61 ± 0.03 | 0.62 ± 0.20 | 0 ± 0 | 93 ± 6 | 0.219 ± 0.029 | 0.068 ± 0.004 |
1 | Coffee silverskin | 2.5·108 | 3.28 ± 0.29 | 5.94 ± 0.29 | 0.28 ± 0.01 | 1.96 ± 0.23 | 0.35 ± 0.04 | 0 ± 0 | 79 ± 3 | 0.245 ± 0.004 | 0.062 ± 0.003 | |
5 | Control | 6.7·108 | 1.05 ± 0.13 | 6.52 ± 0.10 | 0.05 ± 0.00 | 1.10 ± 0.03 | 1.00 ± 0.44 | 0 ± 0 | 94 ± 1 | 0.202 ± 0.001 | 0.068 ± 0.001 | |
5 | Coffee silverskin | 3.8·108 | 1.62 ± 0.10 | 5.60 ± 0.23 | 0.13 ± 0.01 | 3.31 ± 0.04 | 1.86 ± 0.26 | 0 ± 0 | 79 ± 5 | 0.207 ± 0.010 | 0.058 ± 0.002 | |
DSM 6423 | 1 | Control | 1.1·109 | 0 ± 0 | 5.98 ± 0.14 | 0.08 ± 0.00 | 0.74 ± 0.06 | 0.52 ± 0.13 | 1.68 ± 0.04 | 94 ± 3 | 0.185 ± 0.011 | 0.062 ± 0.001 |
1 | Coffee silverskin | 4.1·108 | 0 ± 0 | 4.18 ± 0.20 | 0.11 ± 0.00 | 3.87 ± 0.29 | 1.53 ± 0.19 | 1.93 ± 0.06 | 66 ± 2 | 0.184 ± 0.004 | 0.044 ± 0.002 | |
5 | Control | 9.8·108 | 0.03 ± 0.04 | 6.77 ± 0.46 | 0.11 ± 0.01 | 0.74 ± 0.08 | 0.46 ± 0.14 | 2.46 ± 0.21 | 100 ± 0 | 0.198 ± 0.014 | 0.070 ± 0.005 | |
5 | Coffee silverskin | 3.5·108 | 0 ± 0 | 3.53 ± 0.89 | 0.08 ± 0.01 | n.q. | 2.20 ± 0.11 | 0.79 ± 0.12 | 62 ± 1 | 0.166 ± 0.040 | 0.037 ± 0.009 | |
DSM 13864 | 1 | Control | 8.0·108 | 2.36 ± 0.10 | 6.52 ± 0.34 | 0.21 ± 0.01 | 0.54 ± 0.12 | 0.18 ± 0.00 | 0 ± 0 | 99 ± 0 | 0.191 ± 0.010 | 0.068 ± 0.004 |
1 | Coffee silverskin | 4.3·108 | 0.75 ± 0.28 | 1.13 ± 0.53 | 0.08 ± 0.02 | n.q. | 2.53 ± 1.14 | 0 ± 0 | 54 ± 5 | 0.060 ± 0.024 | 0.012 ± 0.006 | |
5 | Control | 7.1·108 | 1.63 ± 0.04 | 7.13 ± 0.24 | 0.13 ± 0.00 | 0.60 ± 0.09 | 0.58 ± 0.13 | 0 ± 0 | 100 ± 0 | 0.209 ± 0.007 | 0.074 ± 0.003 | |
5 | Coffee silverskin | 5.0·108 | 1.71 ± 0.99 | 3.00 ± 1.80 | 0.13 ± 0.04 | n.q. | 2.27 ± 1.06 | 0 ± 0 | 75 ± 10 | 0.111 ± 0.060 | 0.031 ± 0.019 | |
DSM 2152 | 1 | Control | 5.9·108 | 2.53 ± 0.06 | 6.63 ± 0.07 | 0.25 ± 0.03 | 0.64 ± 0.01 | 0.26 ± 0.01 | 0 ± 0 | 97 ± 0 | 0.200 ± 0.002 | 0.069 ± 0.001 |
1 | Coffee silverskin | 2.1·108 | 1.94 ± 0.13 | 2.43 ± 0.09 | 0.10 ± 0.01 | n.q. | 1.88 ± 0.10 | 0 ± 0 | 58 ± 2 | 0.123 ± 0.008 | 0.025 ± 0.001 | |
5 | Control | 1.1·109 | 1.87 ± 0.02 | 7.38 ± 0.32 | 0.47 ± 0.17 | 0.48 ± 0.01 | 0.25 ± 0.00 | 0 ± 0 | 94 ± 3 | 0.228 ± 0.004 | 0.077 ± 0.003 | |
5 | Coffee silverskin | 2.3·108 | 1.59 ± 0.26 | 2.87 ± 0.54 | 0.13 ± 0.02 | n.q. | 0.85 ± 0.18 | 0 ± 0 | 52 ± 7 | 0.160 ± 0.011 | 0.030 ± 0.006 | |