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@PHDTHESIS{Geinitz:958395,
author = {Geinitz, Bertram Michael},
othercontributors = {Büchs, Jochen and Agler-Rosenbaum, Miriam},
title = {{T}ools accelerating the development of unconventional
bioprocesses},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2023-05251},
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 = {Unconventional microbial systems, such as cocultures or gas
utilizing biocatalysts, bear great potential in converting
residues or complex substrates. This thesis demonstrates
three approaches for the characterization of novel systems,
as new techniques for process monitoring and cultivation are
required to develop such processes.Continuous data of the
individual biomass concentrations are necessary to
characterize and optimize coculture processes. Up to now,
primarily offline methods with low temporal resolution have
been applied to determine the culture composition.
Therefore, a noninvasive online monitoring tool based on
scattered light spectra was developed for microtiter plate
cultivations. A coculture containing Lactococcus lactis and
Kluyveromyces marxianus was cultivated to demonstrate the
tools’ potential. Via partial least squares regression of
scattered light spectra, the online determination of the
individual biomass concentrations is possible. The results
were successfully validated by a Coulter counter-analysis,
taking advantage of the different cell sizes of both
organisms. The findings prove the applicability of the new
method to follow the dynamics of cocultures in detail. To
characterize cocultures without complex equipment and
know-how, a microtiter plate for the spatially separated
cultivation was designed. Via microfiltration channels in
the bottom plate, metabolites can be exchanged between the
two linked wells. The mass transfer was characterized in
abiotic experiments and compared to modeled cocultivations.
It was revealed that the cocultivation in the Link-Plate
significantly increases the process time; therefore, the
metabolite exchange between the linked wells needs to be
increased in the future.The biocatalytic utilization of
methane originating from waste streams or renewable
resources can reduce the carbon footprint of production
processes. However, gas fermentation processes are often
characterized in serum bottles leading to a changing
availability of gaseous substrates over time. Since gas
consumption and production rates are thus unknown, knowledge
gain is limited. Therefore, Methylococcus capsulatus, an
aerobic methanotrophic bacterium, was cultivated in
semi-continuously ventilated shake flasks allowing for
simultaneous monitoring of the respiratory activity. The
methane and oxygen concentrations for ventilation of the
shake flasks were calculated to omit explosion hazards while
supplying as much substrate as possible. It was demonstrated
that the device substantially supports the characterization
of aerobic methane utilizing microorganisms.},
cin = {416510},
ddc = {620},
cid = {$I:(DE-82)416510_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2023-05251},
url = {https://publications.rwth-aachen.de/record/958395},
}
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