% 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{deWitt:1031968,
author = {de Witt, Jan},
title = {{B}iodegradation and microbial upcycling of plastics},
volume = {289},
school = {Düsseldorf},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2024-05892},
isbn = {978-3-95806-804-9},
series = {Schriften des Forschungszentrums Jülich Reihe
Schlüsseltechnologien / Key Technologies},
pages = {XVI, 259},
year = {2024},
note = {Dissertation, Düsseldorf, 2024},
abstract = {Plastics have undoubtedly revolutionized our daily lives,
becoming irreplaceable in several sectors, including
packaging, healthcare, and automotive industries. However,
current endof- life strategies cannot cope with the
increasing global production, which exceeded 400 million
tons in 2022, leading to a global plastic pollution crisis.
Biological catalysis has the potential to overcome the
drawbacks of conventional recycling, using enzymes and
microbes for the depolymerization of plastics and their
subsequent conversion to value-added compounds. To
facilitate the transition towards a circular plastics
economy, the overall goal of this thesis is to provide new
biological end-of-life solutions for plastics. Therefore,
the substrate range of the biotechnological workhorse
Pseudomonas putida KT2440 was expanded with prevalent
plastic hydrolysates providing them as feedstock for
microbial upcycling. Deep metabolic engineering enabled the
utilization of polyamide (PA) hydrolysates as a carbon
source, while RNA-sequencing revealed the synthetic
metabolic routes and how they mesh with the native
metabolism. In parallel, new nylonase enzymes were
discovered and characterized that showed activities towards
PA and poly(esteramides). In addition to PA-derived
compounds, metabolic routes for dicarboxylic acids and diols
were established and their combination yielded a powerful
platform strain that fully metabolized a complex polyester
mock hydrolysate. Moreover, rational metabolic design
enabled the degradation of branched short-chain
dicarboxylates, including itaconic acid, thereby further
expanding the metabolic palette of Pseudomonas with plastic
monomers. To close the life cycle of plastic waste,
hydrolysates should not only be metabolized but also
upcycled. This was achieved by converting the newly
accessible plastic-derived feedstocks into
polyhydroxyalkanoates, demonstrating, among others, the
conversion of nylon to polyhydroxybutyrate through
hydrolysis and microbial conversion. The resulting products
are environmentally benign due to their biodegradability and
resources are maintained in the material cycle, reducing the
production of virgin fossil-based plastics. With regard to a
circular plastics economy, it is essential to consider
plastic coatings as an additional source of complexity in
plastic waste. For this, the novel Halopseudomonas
formosensis FZJ was isolated from a compost heap due to its
ability to metabolize poly(ester-urethane) coatings. The
detailed characterization of its metabolic pathways and
enzymes provides the scientific basis for future
bio-recycling processes of coated plastics and thus
increasingly complex materials.},
cin = {IBG-1},
cid = {I:(DE-Juel1)IBG-1-20101118},
pnm = {2172 - Utilization of renewable carbon and energy sources
and engineering of ecosystem functions (POF4-217)},
pid = {G:(DE-HGF)POF4-2172},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2503060801542.370078637444},
doi = {10.34734/FZJ-2024-05892},
url = {https://juser.fz-juelich.de/record/1031968},
}