Fig. 3

mluc mRNA and protein expression analysis throughout a time-course of perfusion cultivation. a Quantification of mRNA abundance from Northern blot analyses with the mluc probe demonstrated gene expression directed by the anafp promoter in strain PK2.9 was highest following 5 days perfusion cultivation, which was also the case for promoter PhfbD in strain PK4.3. As a control, mRNA abundance for the housekeeping gene actin was measured in strain PhfbD::mluc, which demonstrated a decrease in relative transcript abundance over time (closed circles). b Protein abundance was measured as luminescent counts per second normalized to culture optical density, which clearly demonstrated highest protein concentration in strain PK2.9 using the anafp promoter when compared to isolate PK4.3 (PhfbD)