TABLE 2.
Glycerol fermentation of the single-nucleotide mutant E. colia
| Strain | Population or mutated gene | Glycerol (mM) |
Fermentation product concn (mM) |
OD600 | pH | Protein (amino acid mutation) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Added | Consumed | Succinate | Formate | Acetate | Ethanol | |||||
| Reference | Ancestor | 84.7 ± 3.7 | 27.5 ± 5.7 | 3.8 ± 0.6 | 0 | 10.2 ± 3.0 | 19.1 ± 5.7 | 1.1 ± 0.1 | 6.8 ± 0.1 | No variation |
| 39th | 84.6 ± 4.4 | 69.4 ± 9.9 | 20.1 ± 1.6 | 0 | 16.2 ± 2.6 | 39.7 ± 11.2 | 1.2 ± 0.1 | 5.8 ± 0.1 | Contained in all 84 variations | |
| Single-nucleotide mutant E. coli | dnaK (b0014) | 79.7 ± 1.7 | 73.2 ± 3.5 | 13.9 ± 0.9 | 0 | 20.3 ± 5.4 | 43.8 ± 3.8 | 1.1 ± 0 | 6.1 ± 0.1 | Chaperone Hsp70 (A586E) |
| ybbP (b0496) | 85.4 ± 3.3 | 77.3 ± 3.1 | 14.5 ± 1.3 | 0 | 22.2 ± 6.7 | 48.9 ± 8.1 | 1.2 ± 0.1 | 6.0 ± 0.2 | Putative ABC transporter permease (W612R) | |
| fdrA (b0518) | 85.1 ± 6.0 | 64.9 ± 3.2 | 16.4 ± 1.0 | 0 | 21.0 ± 4.1 | 33.5 ± 7.7 | 1.0 ± 0 | 6.0 ± 0.1 | Putative NAD(P)-binding acyl-CoA synthetase (D296Y) | |
| pgpC (b2560) | 90.5 ± 3.5 | 45.0 ± 2.6 | 16.0 ± 0.6 | 0 | 19.7 ± 0.6 | 15.1 ± 1.6 | 0.8 ± 0 | 6.1 ± 0.1 | Phosphatidylglycerol phosphatase C (R91L) | |
| yfjI (b2625) | 86.1 ± 5.0 | 73.6 ± 1.4 | 14.8 ± 0.4 | 0 | 24.1 ± 1.7 | 41.5 ± 1.1 | 1.1 ± 0.1 | 5.9 ± 0.1 | Uncharacterized protein (I384V) | |
| cysN (b2751) | 82.8 ± 5.4 | 77.3 ± 3.0 | 14.7 ± 0.2 | 0 | 20.3 ± 6.4 | 50.2 ± 4.2 | 1.2 ± 0.1 | 6.1 ± 0.1 | Sulfate adenylyltransferase subunit 1 (D171E) | |
| rob (b4396) | 83.9 ± 5.0 | 74.7 ± 7.0 | 14.1 ± 2.2 | 0 | 16.1 ± 7.2 | 51.3 ± 11.7 | 1.1 ± 0.1 | 6.1 ± 0.1 | Right oriC-binding transcriptional activator (R156S) | |
a
The glycerol fermentation of E. coli was performed as coculture with M. formicicum for 96 h under anaerobic condition. Seven E. coli strains were selected after evaluating the fermentation of a total 84 mutant strains, and they accounted for more than 75% of the succinate production observed in the 39th population. Values are averages and SD for 3 replicates.