Table 6.
Application of the multi-stage process for continuous solvent production with solventogenic and acetogenic clostridia
| Strain | Continuous system | 1st stage | 2nd stage | Substrate | Product | Titer, productivity, yield | References |
|---|---|---|---|---|---|---|---|
| C. acetobutylicum DSM 1731 | Two-stage chemostat | D 0.125 h−1, P-limited | D 0.04 h−1, P-limited | Glucose | Butanol | 130 mM | [14] |
| Acetone | 74 mM | ||||||
| C. acetobutylicum IFP 918 | Two-stage chemostat | D 0.16 h−1, pH 6.1, T 36 °C | D 0.045 h−1, pH 5.5, T 33 °C, N-limited | Glucose | ABE solvents | 0.28 g g−1 | [18] |
| C. acetobutylicum | Two-stage fermentation | D 0.08 h−1, pH 4.5 | D 0.04 h−1, pH 4.5–5.0 | Glucose | ABE solvents | 21 g L−1, 0.36 g g−1 | [91] |
| C. acetobutylicum ATCC 824 | Two-stage chemostat | D 0.075 h−1, pH 6.0, T 37 °C, N-limited, acid formation | D 0.06 h−1, pH 4.5, T 33 °C, solvent production | Glucose | ABE solvents | 9.11 g L−1, 0.6 g L−1 h−1 | [154] |
| Butanol | 5.93 g L−1, 0.4 g L−1 h−1 | ||||||
| C. acetobutylicum ATCC 824 |
Two-stage turbidostat/ chemostat |
pH 4.62, acid formation | pH 4.37, solvent production and in situ product recovery | Glucose | ABE solvents | 18.0 g L−1, 0.13 g L−1 h−1, 0.30 g g−1 | [305] |
| C. acetobutylicum B 5313 | Two-stage chemostat and cell immob., in situ product recovery | D 0.6 h−1, 37 °C | D 0.3 h−1, 37 °C | Glucose | ABE solvents | 25.32 g L−1, 2.5 g L−1 h−1, 0.35 g g−1 | [17] |
| C. beijerinckii NRRL B592 | Two-stage cascade and cell immobilization | D 0.5–0.6 h−1, pH 4.6–4.7, T 36 °C | D 0.15–0.20 h−1, pH 4.7–4.8, T 36 °C | Glucose | ABE solvents | 9.27 g L−1, 1.24 g L−1 h−1 | [88] |
| Butanol | 5.57 g L−1 | ||||||
| C. beijerinckii NRRL B592 | Two-stage cascade | Turbidostat, D 0.12 h−1, pH 4.7, 34 °C, acid formation | Chemostat, D 0.022 h−1, pH 4.7, 34 °C, solvent production | Glucose | ABE solvents | 15 g L−1, 0.27 g L−1 h−1 | [205] |
| Butanol | 9.1 g L−1 | ||||||
|
C. beijerinckii DSM 6423 |
Two-stage chemostat | D 112 h−1, pH 4.8 | D 0.054 h−1, pH 5.1 | Glucose | ABE solvents | 10.56 g L−1, 0.39 g L−1 h−1 | [279] |
| C. ragsdalei ATCC PTA-7826 | Two-stage cascade with cell recycle and nutrient limitation | D 0.28 mL min−1, acid formation | D 0.28 mL min−1, ethanol production | Syngas: 30% H2, 30% CO2, 40% CO | Ethanol | (14.74 g g−1 cells) | [153] |
|
C. ljungdahlii ERI-2 (ATCC 55380) |
Two-stage cascade | CSTR, pH 5.5–5.7, growth stage | Bubble column, pH 4.4–4.8, with cell and gas recycle ethanol production | Syngas: 60% CO, 35% H2, 5% CO2 | Ethanol | 450 mM, 0.37 g L−1 h−1 | [247] |
| C. ljungdahlii PETC | Two-stage chemostat | CSTR D 0.96 day−1, pH 5.5 | Bubble column with cell recycle, D 0.48 day−1, pH 4.5 | Syngas: 60% CO, 35% H2, 5% CO2 | Ethanol | 19 g L−1, 0.30 g L−1 h−1 | [191] |
| C. ljungdahlii PETC | Two-stage chemostat | Acid formation | Ethanol production | Syngas: 60% CO, 35% H2, 5% CO2 | Ethanol | 188.2 mM | [249] |
The table gives an overview of the settings of the most investigated two-stage process, in detail: dilution rate (D), pH, temperature (T), nutrient limitation (P: phosphate, N: nitrogen) and purpose of the respective stage