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@PHDTHESIS{Lchtrath:1011757,
author = {Lüchtrath, Clara Agnes},
othercontributors = {Schillberg, Stefan Johannes and Büchs, Jochen},
title = {{A}dvancing diffusion-driven small-scale fed-batch
technologies},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-04706},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, RWTH Aachen University, 2025},
abstract = {The fed-batch cultivation mode is the most prevalent in
industrial bioprocesses, as it effectively mitigates a
multitude of detrimental phenomena, including overflow
metabolism, mixed acid formation, and oxygen limitation. To
achieve the most efficient industrial-scale bioprocess, it
is essential that the process development is performed in
fed-batch. Consequently, a variety of fed-batch technologies
for microtiter plates and shake flasks have been developed.
In this study, two bioreactor systems were employed: the
commercially available diffusion-driven FeedPlate® for
microtiter plates and the membrane-based fed-batch system
for shake flasks. In the FeedPlate® system, the glucose is
embedded in a silicone matrix and released upon contact with
the culture medium. In the membrane-based fed-batch shake
flask, the feed solution is stored in a glass reservoir
connected to a membrane-sealed diffusion tip. The feed
solution is released upon contact with the culture broth.
This thesis employs diffusion-driven fed-batch techniques to
investigate enzyme production in the fast-growing host
Vibrio natriegens. Given the striking overflow metabolism
and mixed acid formation, it was hypothesized that fed-batch
fermentation would result in higher enzyme yields. Induction
profiling revealed notable dependencies on the yield in
batch processes, which were not observed in fed-batch
processes. Moreover, the membrane-based fed-batch shake
flask was applied to simulate a co-cultivation of
Synechococcus elongatus and Ustilago maydis. To investigate
the impact of a co-culture wherein S. elongatus releases
minimal quantities of sucrose, the growth of U. maydis under
these conditions was monitored. It was demonstrated that U.
maydis exhibits growth under conditions with feeding rates
of 1 mg/h. To further exploit the potential of
membrane-based feeding in shake flasks, the established
feeding system was implemented in perforated ring flasks.
The combination of membrane-based feeding and the novel
flask geometry enables high oxygen transfer rates even at
elevated filling volumes and lower shaking frequencies.
Therefore, it could be a useful tool for screening
applications. Additionally, a feasibility study was
conducted to examine if an increasing feed rate can be
established in the membrane-based fed-batch shake flask by
introducing an intermediate chamber. For the feasibility
study, a mathematical model was created. Parameter variation
within this model revealed that increasing feed rates during
a cultivation process are not feasible with the current
design of the 3-chamber system. The presented work
highlights the potential of diffusion-driven feeding
systems. In future works, these systems can help to improve
strain screening, process development and the research of
co-cultivations.},
cin = {162910 / 160000 / 416510},
ddc = {570},
cid = {$I:(DE-82)162910_20140620$ / $I:(DE-82)160000_20140620$ /
$I:(DE-82)416510_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2025-04706},
url = {https://publications.rwth-aachen.de/record/1011757},
}
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