TABLE 2.
Comparison of secretion-engineered P. pastoris strains and their parental strain in fed-batch cultivationsa
| Strainb | Mean qP (mg g−1 h−1) | Mean μ (h−1) | QP maximum (mg liter−1 h−1) | YDM (g liter−1) | hFab (mg liter−1) | Total YDM (g) | Total product (mg hFab) | YP/X (mg g−1) | Y′X/S |
|---|---|---|---|---|---|---|---|---|---|
| Control | 0.0085 | 0.0249 | 0.2585 | 94.2 | 47.3 | 220.2 | 66.9 | 0.36 | 0.46 |
| BFR2 | 0.0105 | 0.0245 | 0.3172 | 94.2 | 58.4 | 219.5 | 83.0 | 0.44 | 0.42 |
| BMH2 | 0.0141 | 0.0223 | 0.4303 | 82.0 | 62.2 | 185.9 | 95.0 | 0.57 | 0.39 |
| CUP5 | 0.0143 | 0.0265 | 0.4443 | 99.8 | 86.5 | 229.8 | 112.5 | 0.60 | 0.46 |
| KIN2 | 0.0185 | 0.0243 | 0.6491 | 95.3 | 106.0 | 220.2 | 144.9 | 0.78 | 0.47 |
| PDI1 | 0.0187 | 0.0236 | 0.5968 | 87.6 | 89.2 | 201.1 | 134.5 | 0.74 | 0.43 |
| SSA4 | 0.0154 | 0.0252 | 0.4562 | 93.9 | 81.8 | 211.1 | 110.1 | 0.62 | 0.48 |
| SSE1 | 0.0211 | 0.0254 | 0.5982 | 94.6 | 108.5 | 212.9 | 152.1 | 0.81 | 0.48 |
a
Abbreviations: μ, average growth rate; YDM, final biomass concentration; hFab, final product concentration; YP/X, product yield; Y′X/S, observed biomass yield coefficient (g YDM per g glucose). Total YDM is calculated as biomass concentration times culture volume; total product is determined as hFab volume in the free culture volume (total volume as deducted by the YDM).
b
The control is P. pastoris SMD1168, expressing only the 2F5 Fab fragment under the control of the GAP promoter, whereas BFR2, BMH2, CUP5, KIN2, PDI1, SSA4, and SSE1 are coexpressing the respective S. cerevisiae genes identified as secretion helper factors.