Table 1 The performance of enzymatic hydrolysis and ABE fermentation under various citrate buffer strengths using corn stover
Sodium citrate buffer strengths (mM) | ||||||||
|---|---|---|---|---|---|---|---|---|
20 | 30 | 40 | 60 | 80 | 100 | 100 (dilute) | 30 (dilute) | |
Initial glucose, g/L | 45.7 | 45.1 | 46.8 | 47.4 | 47.1 | 46.1 | 23.5 | 23.8 |
Initial xylose, g/L | 17.9 | 18.4 | 18.5 | 18.0 | 18.6 | 20.5 | 9.9 | 9.8 |
Initial cellobiose, g/L | 6.6 | 6.3 | 6.7 | 6.5 | 6.4 | 6.9 | 2.7 | 3.7 |
Initial arabinose, g/L | 1.8 | 1.5 | 2.8 | 2.1 | 1.5 | 1.5 | 0.9 | 0.8 |
Residual glucose, g/L | 19.0 | 14.2 | 16.9 | 19.6 | 26.0 | 27.0 | 2.2 | 0.2 |
Residual xylose, g/L | 6.5 | 8.7 | 11.2 | 7.5 | 8.1 | 8.1 | 2.6 | 2.2 |
Maximum OD | 2.4 | 2.9 | 2.6 | 1.9 | 1.3 | 1.0 | 1.9 | 2.6 |
Fermentation time, h | 60 | 60 | 60 | 60 | 60 | 60 | 48 | 48 |
Butanol, g/L | 9.4 | 11.2 | 8.2 | 8.0 | 7.1 | 6.4 | 6.5 | 6.1 |
Acetone, g/L | 6.0 | 7.5 | 5.0 | 5.0 | 4.7 | 4.4 | 3.3 | 3.9 |
Ethanol, g/L | 0.4 | 1.1 | 0.4 | 0.4 | 0.3 | 0.3 | 0.2 | 0.2 |
Total ABE, g/L | 15.8 | 19.8 | 13.6 | 13.4 | 12.1 | 11.1 | 10.0 | 10.2 |
Butanol yield, g/g | 0.25 | 0.28 | 0.22 | 0.21 | 0.22 | 0.20 | 0.23 | 0.20 |
Butanol productivity, g/L/h | 0.16 | 0.19 | 0.14 | 0.13 | 0.12 | 0.11 | 0.14 | 0.13 |
Acetic acid, g/L | 2.4 | 3.6 | 2.8 | 3.6 | 2.6 | 1.9 | 2.4 | 3.0 |
Butyric acid, g/L | 3.6 | 0.3 | 2.6 | 1.0 | 0.4 | 0.6 | 0.6 | 1.9 |