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@PHDTHESIS{Bongartz:960419,
      author       = {Bongartz, Patrick},
      othercontributors = {Wessling, Matthias and Blank, Lars M.},
      title        = {{N}ext generation bioreactor design for gas fermentation},
      volume       = {38 (2023)},
      school       = {Rheinisch-Westfälische Technische Hochschule Aachen},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {Aachener Verfahrenstechnik},
      reportid     = {RWTH-2023-06246},
      series       = {Aachener Verfahrenstechnik series - AVT.CVT - chemical
                      process engineering},
      pages        = {1 Online-Ressource : Illustrationen, Diagramme},
      year         = {2023},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, Rheinisch-Westfälische Technische
                      Hochschule Aachen, 2023},
      abstract     = {Bioreactors are the production units of an expansive
                      variety of high-value products in the pharmaceutical and
                      biotech industry. They enable the efficient cultivation and
                      expansion of bacteria, fungi, plant and animal cells.
                      Products of these life forms e.g., proteins as enzymes,
                      therapeutic molecules, the cells themselves, can be
                      exploited for industry and medicine. Present methods of
                      bioreactor aeration cannot provide high gas input at
                      physiologic mixing conditions. Bioreactors can provide high
                      oxygen transferrates (OTRs) only with accompanying high
                      shear forces, which results in a drawback in several process
                      due to the shear stress on the sensitive organisms.
                      Additionally, foam formation, caused by the bubbles and
                      surface active ingredients of the fermentation broth, lowers
                      the vessels available reaction volume. To overcome this
                      challenges, aim of this work is the development of a
                      technology for the bubble-free aeration of microbial
                      fermentations. Due to the diffusive gas input by usage of
                      membrane aeration, bubble usage or formation should be
                      avoided. As none of the recent membrane aeration
                      technologies fulfill the oxygen demands of a microbial
                      process, novel in situ membrane aeration approaches were
                      designed and tested. Therefore, an aeration membrane
                      originally used in medical application, and CFD simulations
                      were utilized to gain an optimized module architecture. With
                      a static membrane module with air, an OTRmax of 5.7 mmol
                      L−1 h−1 was reached, what is $475\%$ more then in
                      commercially available membrane aeration modules. For
                      intensification of a benchmark bioprocess for production of
                      biosurfactants (Rham-nolipids, RL), the static membrane
                      aeration module was additionally equipped with a
                      cell-retention membrane. This cell-retention enables the
                      direct, in-line transfer of the fermentation broth to a
                      solvent extraction setup. A foam-free air aeration with
                      parallel product extraction could be achieved for 46 hours
                      by this system. To further improve the gas transfer
                      performance, a dynamic membrane module was de-signed,
                      combining the stirrers and the aeration function. The
                      membrane module stirrer(MemStir) enables an OTRmax of 175
                      mmol L−1 h−1. Versatility of the MemS is shown by RL
                      fermentation with Pseudomonas putida in batch and fed-batch.
                      A direct comparison with a bubble aerated cultivation was
                      made and hurdles in product analytics and downstreaming due
                      to the antifoam are presented. A space-time-yield (STY) up
                      to 124 mgRL L−1 h−1 was reached with the MemStir. This
                      STY is almost identical with recent state-of-the-art
                      fermentation approaches for RL synthesis, but with a
                      significantly less complex operation. Beyond rhamnolipid
                      production, this thesis discusses the applicability of the
                      presented MemStir for the cultivation of vulnerable cells
                      like animal cells. The CFD results indicate physiological
                      flow conditions and oxygen supply with reduced harm to those
                      cells.},
      cin          = {416110},
      ddc          = {620},
      cid          = {$I:(DE-82)416110_20140620$},
      pnm          = {BioSC - Bioeconomy Science Center (BioSC)},
      pid          = {G:(DE-Juel1)BioSC},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      doi          = {10.18154/RWTH-2023-06246},
      url          = {https://publications.rwth-aachen.de/record/960419},
}