% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@PHDTHESIS{Jeude:62434,
author = {Jeude, Markus},
othercontributors = {Büchs, Jochen},
title = {{E}ntwicklung und {A}nwendung einer
{F}ed-batch-{B}etriebsweise mit
{N}ährstofffreisetzungssystemen zur kontrollierten
{K}ultivierung und zum {S}creening von {M}ikroorganismen in
{S}chüttelreaktoren},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-124003},
pages = {XVII, 262 S. : Ill., graph. Darst.},
year = {2007},
note = {Aachen, Techn. Hochsch., Diss., 2007},
abstract = {Most industrial production processes are performed in
fed-batch operational mode. In contrast, the screenings for
microbial production strains are run in batch mode which
results in completely different physiological conditions
than relevant for production. This may lead to wrong strain
selections. Silicone elastomer discs containing glucose
crystals were developed to realize fed-batch fermentation
based on diffusion in shaken bioreactors. No other device
for feeding was required. This “slow-release fed-batch
technique” was tested on the metabolism of H. polymorpha,
E. coli and G. oxydans in shake flasks. The OTR and RQ were
monitored online with a RAMOS device. Biomass formation,
synthesis of proteins like GFP or eYFP-IL-6, pH drift and
metabolic dynamics of glucose, ethanol, acetic acid and
other organic acids were measured offline. By application of
the slow-release fed-batch technique in comparison to
regular batch mode, overflow-metabolism of H. polymorpha and
E. coli could be reduced, which led to an increase in
biomass yield of up to $85\%$ and $59\%,$ respectively. Up
to date, 23.4 g/L cell dry weight of H. polymorpha and 13.7
g/L of E. coli was achieved. The specific biomass yields of
0.38-0.47 are in the magnitude of those in laboratory
fermentors equipped with a substrate feed-pump. The GFP
expression by H. polymorpha RB11 pC10-GFP could be improved
in Syn6-MES and YNB mineral media up to 35-fold and
420-fold, respectively. The synthesized maximum in fed-batch
mode was 421 mg/L GFP. In contrast only up to 2.5 mg/L GFP
was received in batch mode. The expression of eYFP-IL-6 by
E. coli BL21 pLys pRSET eYFP-IL6 could be increased 4-fold
in optimized Wilms-MOPS mineral medium using the
slow-release fed-batch technique. Slow-release fed-batch
cultures of G. oxydans DSM 2003 revealed a 2.6-fold increase
of specific biomass yield in modified Silberbach-MES complex
medium. A cell dry weight of 3.3 g/L was obtained in
contrast to 1.6 g/L in batch mode. Due to glucose feeding a
reduction of gluconic acid as well as 2- and 5-ketogluconic
acid formation was monitored. A mass screening of 265 H.
polymorpha RB11 pC10-FMD clones and 267 pC10-MOX clones was
performed in Syn6-MES mineral medium in deep-well plates. A
batch with glucose and one with glycerol were performed
simultaneously in comparison to a slow-release fed-batch
with glucose. One repetition screening was done under the
same conditions. These diverse operational modes revealed
great differences in strain selection and quality of
specific GFP yield. The best strains for a fed-batch would
be unlikely found in either batch mode. A dependence on the
carbon source and the operational mode was found in
relevance to the regulating promoter for gene expression. A
fed-batch screening points out to be the most secure way to
select the right strain for a fed-batch production process.},
keywords = {Fed-batch-Verfahren (SWD) / Schüttelkolben (SWD) /
Hansenula polymorpha (SWD) / Escherichia coli (SWD) /
Gluconobacter oxydans (SWD) / Diffusion (SWD) / Glucose
(SWD) / Grün fluoreszierendes Protein (SWD) / Freisetzung
(SWD)},
cin = {416510},
ddc = {570},
cid = {$I:(DE-82)416510_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-19909},
url = {https://publications.rwth-aachen.de/record/62434},
}
guest ::