TABLE 2.
Accumulation of protocatechuic acid by the ΔphyA ΔprcA mutanta
| Substrate | Compound detected in reference strain | ΔphyA ΔprcA mutant |
|
|---|---|---|---|
| Concn (mM) of compound detected | Conversion rate (%) | ||
| Protocatechuic acid | – | 1.68 ± 0.03 | 84.0 |
| Protocatechuic aldehyde | – | 1.95 ± 0.11 | 97.5 |
| Benzoic acid | – | 1.60 ± 0.02 | 80.0 |
| Benzaldehyde | – | 1.95 ± 0.10 | 97.5 |
| Benzyl alcohol | – | 1.78 ± 0.15 | 88.9 |
| p-Anisic acid | – | 1.66 ± 0.11 | 83.0 |
| p-Anisaldehyde | – | 2.09 ± 0.02 | ≥99.0 |
| p-Anisyl alcohol | – | 1.63 ± 0.11 | 81.5 |
| p-Hydroxybenzoic acid | – | 1.81 ± 0.05 | 90.5 |
| p-Hydroxybenzaldehyde | – | 2.10 ± 0.06 | ≥99.0 |
| p-Hydroxybenzyl alcohol | – | 1.90 ± 0.02 | 95.0 |
| m-Hydroxybenzoic acid | – | 1.69 ± 0.20 | 84.5 |
| p-Coumaric acid | – | 1.82 ± 0.05 | 91.0 |
| Caffeic acid | – | 2.10 ± 0.09 | ≥99.0 |
| Cinnamyl alcohol | – | 0.83 ± 0.03 | 41.5 |
| Cinnamic acid | – | 0.28 ± 0.03 | 13.7 |
| Ferulic acid | – | – | – |
| Vanillin | – | – | – |
| Veratric acid | – | – | – |
| p-Cresol | – | – | – |
| Anethole | – | – | – |
| Bitter almond oilb | – | 1.63 ± 0.04 | 81.5 |
| Mixturec | – | 10.32 ± 0.31 | ≥99.0 |
a
The protocatechuic acid concentrations were determined from the average of biological triplicates. A 2 mM concentration was used as the starting substrate. –, no compound detected.
b
Bitter almond oil consists mainly of benzaldehyde (96% to 98%) (28–31); the molecular weight of benzaldehyde was used to obtain approximately 2 mM.
c
The mixture consisted of 2 mM benzaldehyde, 2 mM benzoic acid, 2 mM p-hydroxybenzoic acid, 2 mM p-coumaric acid, and 2 mM caffeic acid.