The bioeconomy is a paramount pillar in the mitigation of greenhouse gas emissions and climate change. Still, the industrialization of bioprocesses is limited by economical and technical obstacles. The synthesis of biosurfactants as advanced substitutes for crude‐oil‐based surfactants is often restrained by excessive foaming. We present the synergistic combination of simulations and experiments towards a reactor design of a submerged membrane module for the efficient bubble‐free aeration of bioreactors. A digital twin of the combined bioreactor and membrane aeration module was created and the membrane arrangement was optimized in computational fluid dynamics studies with respect to fluid mixing. The optimized design was prototyped and tested in whole‐cell biocatalysis to produce rhamnolipid biosurfactants from sugars. Without any foam formation, the new design enables a considerable higher space–time yield compared to previous studies with membrane modules. The design approach of this study is of generic nature beyond rhamnolipid production.

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Ultrafiltration membrane modules suffer from performance losses that arise during filtration from concentration polarization and fouling. Such performance losses are frequently mitigated by controlling the hydrodynamic conditions at the membrane/fluid interface. For instance, the hydrodynamic conditions are manipulated using mesh spacers that act as a static mixer. The design of such spacers is rarely optimized to effectively maintain mass transport through the membrane. Also, the spacer is an additional part added to the feed channel of the membrane module, improving mass transport in general, yet accepting less transport in dead zones.Here, we present a mini module with spacers embedded in the module housing of a flat-sheet ultrafiltration membrane to attain high permeation rates. The performance of two new embedded spacer geometries -staggered herringbone and sinusoidal corrugation -prove experimentally that indeed a CFD-simulated flux increase can be realized during bovine serum albumin (BSA) filtration. The flow characteristics inside the mini module are further investigated using magnetic resonance velocity imaging. The new embedded sinusoidal corrugation spacers outperform conventional mesh spacer inlays. The fabrication of such module-embedded spacers has been conceptually implemented through an in-silico design and a 3D-printing production process. The latter can be easily realized using injection molding processes, as is now done for the Sartorius ambr ® crossflow product line.

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