Table 2.
An example of a two level experimental design having nine factors that are known to influence recombinant protein expression. In this case the nine factors relate to two experimental components; media composition and induction conditions. When planning the screening phase the selected factors (yeast extract, tryptone, glycerol, NaCl, Inoculum size, IPTG concentration, induction temperature, incubation time and pH, labelled X1 to X9 respectively) and associated levels (high, defined as +1 and low defined as −1 are selected to cover the intended experimental space (i.e., to cover the productive range). The levels are defined as the range between the known working limits.
| Factors | Levels | ||
|---|---|---|---|
| Low | High | ||
| Media composition | X1 Yeast Extract | − | + |
| X2 Tryptone | − | + | |
| X3 Glycerol | − | + | |
| X4 NaCl | − | + | |
| Induction condition | X5 Inoculum size | − | + |
| X6 IPTG concentration | − | + | |
| X7 Induction temperature | − | + | |
| X8 Incubation time | − | + | |
| X9 pH | − | + | |