Fig. 1.

Reduction of the iron concentration in BSM prevents precipitation. The effect of reduced FeSO₄ concentrations on medium stability and growth of P. pastoris in BSM was investigated in microscale cultivation (4% d-glucose, 150 mM PIPPS, pH 5.0, 0.8 mL, 1500 rpm, 30 °C). Different media were inoculated from the same pre-culture to an initial OD₆₀₀ = 0.3 to ensure equal starting conditions. a 0.92 mM FeSO₄ (original concentration); b 0.46 mM FeSO₄; c 92 µM FeSO₄; d 9.2 µM FeSO₄. Light colors around solid lines show standard deviations from at least three individual wells