Fig. 7

Maximal extracellular D1.3 scFv concentrations for recombinant B. subtilis 168, DB431 and WB800N. B. subtilis strains were transformed with plasmid pRBBm117 (P ^opt. _xylA -sp _lipA -d1.3scFv-his ₆ ). Cultivation took place in microtiter plates (1250 μL culture volume), baffled shake flasks (150 mL culture volume) and stirred tank bioreactors (2 L culture volume) under aerobic conditions at 37 °C. All cultivation systems were inoculated with cell concentrations (cell dry weight) of 0.0337 g L⁻¹ in minimal medium containing 10 mg L⁻¹ of tetracycline. Recombinant D1.3 scFv secretion was induced by the addition of 5 g L⁻¹ of xylose at cell concentrations of around 0.10 g L⁻¹. Extracellular concentration of D1.3 scFv [mg L⁻¹] for B. subtilis 168, DB431 and WB800N was analyzed using ELISA. Further analyses are shown in Additional file 1: Figures S3–S6