Fig. 1.

Schematic overview of the production process development. The modular expression cassette comprises a sequence encoding a truncated version of the GLA-1 (gla _t), the product gene ht186-d11, and positions for various promoters and tags. Initial tests for optimization of the expression system were conducted in shake flasks cultures. For the subsequent process optimization a parallel bioreactor system was employed. Finally, a first scale-up approach in a 10 L stirred tank reactor was carried out. All optimizations were based on a design-build-test-cycle approach