TABLE 3.
HPLC metabolite analysis of the wild-type and dhaT::Ll.LtrB mutant strains of C. pasteurianum in standard and butanol-optimized growth media
| Strain by medium type | Cultivation time (h) | Growth (OD600) | Glycerol consumed (g liter−1) | Products formed (g liter−1 [%])a |
Carbon recovery in products (%)c | Butanol selectivity (g g−1)d | |||
|---|---|---|---|---|---|---|---|---|---|
| Butanol | 1,3-PDO | Ethanol | Acidsb | ||||||
| Standard growth medium | |||||||||
| Wild type | 112 | 3.1 | 28.5 | 5.5 ± 0.9 (47.7) | 4.6 ± 0.2 (19.4) | 2.7 ± 0.9 (18.7) | 0.07 ± 0.06 (0.4) | 86.4 | 0.43 |
| dhaT::Ll.LtrB mutant | 97 | 3.0 | 28.0 | 7.1 ± 2.0 (62.8) | 0.79 ± 0.31 (3.4) | 1.4 ± 0.9 (9.7) | 0.31 ± 0.16 (1.8) | 79.1 | 0.74 |
| dhaT::Ll.LtrB [pMTLdhaT] | 107 | 2.8 | 24.4 | 5.0 ± 0.7 (50.9) | 1.6 ± 0.2 (7.7) | 2.6 ± 0.4 (21.3) | 0.25 ± 0.07 (1.5) | 81.9 | 0.54 |
| Optimized growth medium | |||||||||
| Wild type | 102 | 4.1 | 31.8 | 6.7 ± 0.4 (52.1) | 3.6 ± 0.5 (13.7) | 2.9 ± 1.6 (18.2) | 0.72 ± 0.21 (3.6) | 87.7 | 0.51 |
| dhaT::Ll.LtrB mutant | 94 | 4.8 | 32.6 | 8.6 ± 0.1 (65.5) | 0.58 ± 0.07 (2.1) | 0.7 ± 0.1 (4.3) | 0.35 ± 0.07 (1.9) | 75.4 | 0.83 |
a
Product titers are reported as average ± standard deviation of the results from three biological replicates. The percent moles of glycerol consumed in the production of each metabolite is provided in parentheses.
b
Combined titer of acetate, butyrate, and lactate.
c
Calculated as the percent moles of carbon in total liquid products (including 1,2-PDO and excluding biomass and gaseous products) per mole of carbon in glycerol consumed.
d
Reported as grams of n-butanol produced per gram of total solvents (butanol, ethanol, 1,2-PDO, and 1,3-PDO).