Disposable bioreactors have gained an increasing importance in recent years in the pharmaceutical production. Wave‐mixed reactors were among the first systems which were applied. In contrast to stirred tank reactors, wave‐mixed bioreactors are characterized by low shear forces while the gas exchange is realized by the large gas‐liquid interface. Oxygen transfer rates obtained are often in a range between 50 and 300 h–1. By applying nutrient‐limiting fed‐batch cultivations, in which the oxygen consumption of a culture is controlled, bacteria can be also cultivated in wave‐mixed reactors. This article describes the successful scale‐up of an Escherichia coli fed‐batch cultivation from the 12‐L to the 120‐L scale using a disposable bioreactor, in which a final biomass concentration of 45 g L–1 was obtained.

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The observable reaction rate of heterogeneously catalyzed reactions is known to be limited either by the intrinsic kinetics of the catalytic transformation or by the rate of pore and/or film diffusion. Here, we show that in gas generation reactions from liquid reactants, the nucleation of gas bubbles in the catalyst pore structure represents an additional important rate-limiting step. This is highlighted for the example of catalytic hydrogen release from the liquid organic hydrogen carrier compound perhydro-dibenzyltoluene. A nucleation-inhibited catalytic system produces only dissolved hydrogen with fast saturation of the fluid phase around the active site, while bubble formation enhances mass transfer by more than a factor of 50 in an oscillating reaction regime. Nucleation can be efficiently triggered not only by temperature changes and catalyst surface modification but also by a mechanical stimulus. Our work sheds new light on performance-limiting factors in reactions that are of highest relevance for the future green hydrogen economy.