Protease production and process parameters. Process parameters are shown for fermentation L (please refer to Additional file 1: Figure S1 for replicate fermentations R and M). Oxygen partial pressure pO2 [%], glucose concentration cGlucose [g/L], supplied glucose feedGlucose [g/L] and normalized protease activity [%] are displayed on the left y-axis, whereas acetate concentration cAcetate [g/L], carbon dioxide content CO2 [%], and ammonium concentration cNH4+ [g/10 L] are scaled on the right y-axis. The process time t [h] is given on the x-axis. The sampling points I to V are indicated by light blue lines. The figure was modified from Wiegand et al.  where a detailed analysis of RNA-Seq data of the same experimental setup aiming at the identification of regulatory RNAs was performed.