Table 4.
Culture performance and intracellular cofactor levels and ratios for strains engineered to produce xylitol.
| Batch fermentationa | Resting cellsb | Cofactor concentrations μmol (g cdw)-1 |
Cofactor ratios | |||||||
| Glucose consumed (mM) |
Xylitol produced (mM) |
Acetate produced (mM) | Xylitol yieldc |
NADH | NAD+ | NADPH | NADP+ | NADH/NAD+ | NADPH/NADP+ | |
| W3110ΔxylB + pPCC207, GX | 248 | 223 | 19 | 2.5 | 10.3 | 47.9 | 0.3 ± 0.05 | 5.8 | 0.22 | 0.05 |
| W3110ΔxylB + pPCC207, G | - | - | - | - | 10 ± 1.8 | 47.9 | 0.5 | 5.1 ± 1.0 | 0.21 | 0.10 |
| PC05ΔxylB + pLOI3815, GX | 301 | 680 | 1.3 ± 1.4 | 3.9 | 1.8 ± 0.7 | 33.1 | 0.1 ± 0.04 | 9.9 ± 2.3 | 0.05 | 0.01 |
| PC05ΔxylB + pLOI3815, G | - | - | - | - | 3.8 ± 0.7 | 39.2 | 0.8 | 8.7 ± 2.6 | 0.10 | 0.09 |
W3110ΔxylB harboring plasmid pPCC207 expresses CbXR and XylFGH, while PC05ΔxylB harboring plasmid pPLOI3815 expresses CbXR. Strains were grown in the presence of glucose only (G) or in glucose plus xylose (GX), enabling xylose reduction during glucose metabolism. Standard deviations were less than 15% unless noted.
a Reported in Table 4 of reference [26].
b Resting cells were prepared as described [61]. Values reported were measured after 24 hours of biotransformation with cells suspended to OD600 = 2.0.
c Reported as moles xylitol produced per mole glucose consumed.