title: Evaluation of a new mist-chamber bioreactor for biotechnological applications.
abstract: In this article we describe the development, the characterization and the evaluation of a novel bioreactor type for the cultivation of different pro- and eukaryotic cell-systems: the mist-chamber bioreactor. This innovative bioreactor meets the demand of cultivation systems for shear stress sensitive cells with high requirements for gas supply. Within the mist-chamber bioreactor the cells are cultivated inside an aerosol of vaporized medium generated by ultrasonic vaporization. In contrast to many established bioreactor systems the mist-chamber bioreactor offers an environment with an excellent gas supply without any impeller or gas bubble induced shear stress. A mist-chamber bioreactor prototype has been manufactured and characterized during this work. In the technical and chemical characterization we evaluated the vaporization process, resulting in a vaporization performance of 32 mL/h at working conditions. On this basis we calculated a biomass of 1.4 g (S. cerevisiae, qs  = 3.45 × 10-3 mol/g/h) and 3.4 g (Aspergillus niger, qs  = 1.33 × 10-3 mol/g/h) where the growth rate becomes limited by transport processes. Additionally, we determined a homogenous cultivation area to a height of 3 cm giving a total volume of 0.45 L for the cultivation. Medium components were examined according to their stability during vaporization with the result that all components are stable for at least 5 days. After the technical characterization we demonstrated the feasibility to cultivate S. cerevisiae and F. velupites in the mist-chamber bioreactor. The results demonstrated that the mist-chamber bioreactor is able to transport a sufficient amount of nutrients consistently to the cell samples and offers an excellent oxygen supply without any shear stress inducing aeration. Furthermore we successfully cultivated F. velupites in a solid state cultivation in a long term experiment. The data indicate that the new bioreactor concept can contribute to improve various fermentations and cell culture processes depending on the cultured cell types.
authors.affiliation: Institut für Technische Chemie der Leibniz Universität Hannover, Callinstr. 5, D-30167, Hannover, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Tscheschke
authors.forename: Janis
authors.initials: J
authors.lastname: Dreimann
authors.forename: Jürgen W
authors.initials: JW
authors.lastname: von der Ruhr
authors.forename: Timo
authors.initials: T
authors.lastname: Schmidt
authors.forename: Frank
authors.initials: F
authors.lastname: Stahl
authors.forename: Lothar
authors.initials: L
authors.lastname: Just
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheper
mesh_terms: D000336:Aerosols; D001234:Aspergillus niger / Q000254:growth & development; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry*; D055393:Flammulina / Q000254:growth & development; D012441:Saccharomyces cerevisiae / Q000254:growth & development; D014835:Volatilization
chemical_list: D000336:Aerosols; D003470:Culture Media
keywords: mist-chamber bioreactor; new bioreactor concept; optimal oxygen supply; ultrasonic vaporization