Design and evaluation of a 3D-printed, lab-scale perfusion bioreactor for novel biotechnological applications.

3D-printing increased in significance for biotechnological research as new applications like lab-on-a-chip systems, cell culture devices or 3D-printed foods were uncovered. Besides mammalian cell culture, only few of those applications focus on the cultivation of microorganisms and none of these make use of the advantages of perfusion systems. One example for applying 3D-printing for bioreactor development is the microbial utilization of alternative substrates derived from lignocellulose, where dilute carbon concentrations and harmful substances present a major challenge. Furthermore, quickly manufactured and affordable 3D-printed bioreactors can accelerate early development phases through parallelization. In this work, a novel perfusion bioreactor system consisting of parts manufactured by fused filament fabrication (FFF) is presented and evaluated. Hydrophilic membranes are used for cell retention to allow the application of dilute substrates. Oxygen supply is provided by membrane diffusion via hydrophobic polytetrafluoroethylene membranes. An exemplary cultivation of Corynebacterium glutamicum ATCC 13032 supports the theoretical design by achieving competitive biomass concentrations of 18.4 g L after 52 h. As a proof-of-concept for cultivation of microorganisms in perfusion mode, the described bioreactor system has application potential for bioconversion of multi-component substrate-streams in a lignocellulose-based bioeconomy, for in-situ product removal or design considerations of future applications for tissue cultures. Furthermore, this work provides a template-based toolbox with instructions for creating reference systems in different application scenarios or tailor-made bioreactor systems.