TABLE 2.
Percentages of different carotenoid products in cells expressing a mutated crtW gene in the E. coli host harboring the zeaxanthin biosynthetic gene cluster crtZE-idi-crtYIBa
| Mutation | % ofb:
|
||
|---|---|---|---|
| Zeaxanthin | Adonixanthin | Astaxanthin | |
| H65A | 95.0 | 1.0 | — |
| H69A | 55.9 | 35.6 | 2.9 |
| H103A | 90.8 | — | — |
| H106A | 91.1 | — | — |
| H107A | 91.7 | — | — |
| H218A | 53.0 | 40.8 | 2.2 |
| H219A | 1.0 | 45.7 | 47.7 |
| H221A | 93.8 | — | — |
| H222A | 92.0 | — | — |
| H184A | 92.1 | 1.2 | 3.4 |
| D117A | 77.2 | 20.3 | — |
| F130A | 33.6 | 56.5 | 1.3 |
| Y134A | 25.6 | 63.1 | 1.6 |
| Y91A | 10.2 | 65.9 | 11.2 |
| F176A | 23.4 | 64.5 | 3.0 |
| F118A | 13.9 | 67.6 | 10.4 |
| P116A | 1.5 | 62.5 | 20.9 |
| W126A | 5.8 | 60.6 | 25.4 |
| W229A | 1.2 | 64.0 | 25.5 |
| L232A | 1.7 | 65.8 | 24.3 |
| W26A | 1.5 | 21.7 | 67.5 |
| N80A | — | 5.0 | 80.1 |
| G84A | 1.5 | 23.3 | 66.1 |
| W96A | 1.5 | 26.2 | 60.7 |
| D114A | 1.1 | 17.8 | 69.1 |
| D115A | — | 6.2 | 81.4 |
| P228A | 0.9 | 17.7 | 70.1 |
| Wild type | 1.6 | 16.1 | 72.0 |
a
The strain background contained the pSUKMZX construct (Table 1). The total carotenoid titer in this strain was 0.6 mg/g (dry cell weight). The carotenoid products were determined by HPLC with E. coli cells harvested after 8 h of growth. These products were also confirmed by spectral data as described in Materials and Methods.
b
—, trace or nondetectable amount.