Figure 3

Effect of the medium composition and oxygenation on recombinant protein yield. The figure shows the growth curves (a) and Coomassie stained SDS-PAGE of the total protein extract (b) after small scale cultures in medium containing 0.25% yeast extract, 0.4% acetate, low oxygenation (blue curve, lane 1); 0.5% yeast extract, 1% acetate, low oxygenation (red curve, lane 2); 0.5% yeast extract, 0.4% acetate, low oxygenation (yellow curve, 3); 0.5% yeast extract, 0.4% acetate, high oxygenation (green curve, lane 4). Induction of protein synthesis was achieved with 1 mM lactose at 0.6 OD₆₀₀. 5 μg of proteins were loaded in each lane. It is visible how only in the presence of sufficient amounts of yeast extract the growth can be sustained. When enough yeast extract is present, the protein production increases with increasing acetate concentration, whereas it drops when more efficient vessel aeration is applied. See the main text for the description of the high and low oxygenation condition.