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@PHDTHESIS{Schacht:672790,
author = {Schacht, Petra Yvonne},
othercontributors = {Dott, Wolfgang and Blank, Lars Mathias},
title = {{B}ildung, {I}solierung und {N}achweis der mikrobiell
gebildeten {S}peicherstoffe {P}olyphosphat und
{P}olyhydroxybuttersäure bei ausgewählten
{M}ikroorganismen},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2016-08299},
pages = {1 Online-Ressource (186 Seiten) : Illustrationen,
Diagramme},
year = {2016},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, RWTH Aachen University, 2016},
abstract = {The present paper is aimed at investigating to what extent
the production of the microbial reserve substances
polyphosphate and polyhydroxybutyrate can be enhanced and
whether they can be isolated. In addition, the possibility
of utilising these substances beyond their biological
function in the field of environmentally friendly products
and technologies is addressed. Owing to the comprehensive
method development and the examination of both reserve
substances, the present paper consists of three parts,
namely methods of detecting the polymer compounds
polyphosphate and polyhydroxybutyrate, the microbial
production of polyphosphate and the microbial production of
polyhydroxybutyrate. Laboratory-scale test series were
performed to produce the reserve substances polyphosphate
and polyhydroxybutyrate through selective enrichment of
microorganisms. The methods for the isolation as well as the
qualitative and quantitative detection of the reserve
substances were developed and/or established. The produced
polyphosphates were detected qualitatively and
quantitatively by means of microscopy, fluorescence
photometry and gel electrophoresis. The polyphosphates were
quantified after extraction by measurement as
orthophosphate. Due to a lack of uniform standards, however,
the detection methods involve methodological difficulties
regarding the determination of the individual chain lengths
of the polyphosphates and their quantification, which is why
the results should be seen with a critical eye and the
detection methods require optimisation. Nevertheless, a
simultaneous look at the process flow of all employed
detection methods reveals consistent results, which is why
the combination of the employed methods can be regarded as
purposeful. The produced polyhydroxybutyrate was isolated
from the cell and detected qualitatively and quantitatively.
The employed detection methods included microscopy,
enzyme-mediated assay and gas chromatography. The detection
methods for polyhydroxybutyrate yielded satisfactory
results, given the availability of suitable standard
substances. The phosphate uptake and phosphate accumulation
was examined on the basis of the microorganisms in sewage
sludge, giving special regard to the fungus species
Cunninghamella elegans. It was found that phosphate is
accumulated in the cell predominantly as polyphosphate
through the activity of microorganisms. At unfavourable
culture conditions, such as a change in the pH value,
directly or indirectly induced precipitation reactions, such
as the chemical precipitation of struvite (magnesium
ammonium phosphate) occurred additionally. The
carbon/nitrogen/phosphorus ratio in the employed medium was
taken as a basis for the assessment of the test results.
Compared to the microorganisms in the sewage sludge, the
fungus species Cunninghamella elegans was found to be
capable of removing from the medium and accumulating in the
cell as polyphosphate the tenfold amount of phosphate.
Cunninghamella elegans was able to fix a maximum of $10\%$
phosphate in the biomass, whereas the sewage sludge
biocoenosis only fixed $3\%$ of phosphate at maximum.
Cunninghamella elegans produced a promising biomass yield
and accumulated large amounts of phosphate within a short
period of time. However, the technical utilisation of
polyphosphate production is impracticable due to the
necessity of separating the polyphosphates from the biomass,
which is not possible without hydrolysis. The microbial
production and accumulation of polyhydroxybutyrate was
examined on the basis of the bacterial species Paracoccus
denitrificans and Cupriavidus necator. Despite varying
culture conditions and very high carbon consumption, it was
not possible to achieve a high yield of biomass and
polyhydroxybutyrate, which is why the method requires
optimisation. The highest yield of 3-hydroxybutyrate with
Paracoccus denitrificans and Cupriavidus necator amounted to
$50\%$ of the dry weight at maximum. In view of the test
results achieved at laboratory scale, a transfer to
industrial scale should be considered and investigated. The
economical utilisation of the reserve substances requires a
high cell density of microorganisms as well as a high yield.
The tested microorganisms were therefore selected
individually for each reserve substance. The further
processing of industrial wastewater appears to be a starting
point for reducing the production costs of polymers. As part
of the tests, industrial process water was added to the
employed media as a source of phosphate. Despite some
progress in the research into reserve substances, the
isolation of the produced reserve substances from
microorganisms and their quantification is still difficult,
since losses may occur in the course of hydrolysis.At
present, the production and extraction of the microbial
reserve substances polyphosphate and polyhydroxybutyrate is
not yet economical and the method’s technical feasibility
is limited.},
cin = {521000-2 / 161710 / 160000},
ddc = {570},
cid = {$I:(DE-82)521000-2_20140620$ / $I:(DE-82)161710_20140620$ /
$I:(DE-82)160000_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-rwth-2016-082998},
url = {https://publications.rwth-aachen.de/record/672790},
}
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