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TY - THES AU - Grütering, Carolin TI - Producing methyl ketones in integrated bioprocesses; 1. Auflage VL - 34 PB - RWTH Aachen University VL - Dissertation CY - Aachen M1 - RWTH-2024-05867 SN - 978-3-98555-221-4 T2 - Applied microbiology SP - 1 Online-Ressource : Illustrationen PY - 2024 N1 - Druckausgabe: 2024. - Auch veröffentlicht auf dem Publikationsserver der RWTH Aachen University N1 - Dissertation, RWTH Aachen University, 2024 AB - Short- and medium-chain length methyl ketones such as 2-butanone and 2-undecanone are important commodity chemicals that are currently produced from petrochemical resources. To date, there is only limited research regarding the biotechnological production and purification of those methyl ketones in the scope of acircular bioeconomy. This work elucidates integrated bioprocesses for the production of methyl ketones using genetically modified microorganisms. Methyl ketones with a chain length of C11 to C17 are produced by genetically modified Pseudomonas taiwanensis VLB120 in a bioprocess with addition of an organic solvent to the cultivation medium for in situ liquid-liquid product extraction. The applied organicsolvent can decisively influence important process parameters. However, the type ofsolvent for in situ extraction of methyl ketones was not investigated so far, and one ofthe major challenges of in situ liquid-liquid extraction, the formation of stable emulsions, is still unsolved. This work describes an in-depth investigation of theorganic solvent for in situ product extraction of methyl ketones and the subsequent recovery of the organic phase. By performing a hierarchical solvent screening, wefound 2-undecanone as a solvent that is biocompatible, non-biodegradable, and safe.With 2-undecanone as a solvent in an advanced bioreactor setup, the multiphase loopreactor, formation of stable emulsions was successfully circumvented. Here,countercurrent liquid-liquid extraction occurred in a downcomer compartment, and theorganic phase could be recovered by decantation in a coalescing unit. Subsequentexaminations highlighted the methyl ketone blend's potential as a drop-in diesel fuel replacement. Investigations in, e.g., a single-cylinder research engine demonstrated efficient and clean combustion with little NOx and soot emissions.As a next step, the carbon sources that are converted to the C11 to C17 methyl ketonesand the associated feeding strategies were investigated. By an in silico screening approach using a genome-scale metabolic model of the production host, ethanol wasfound as a co-feed carbon source that enabled superior product yields. Additionally, methyl ketone production was shown to be possible by utilizing lignocellulosichydrolysates. Notably, also the hemicellulosic fraction that contains xylose as a carbonsource and inhibitors such as furfural and vanillin was converted to methyl ketones. A bioprocess cascade was also developed for the production of C4 methyl ketonesacetoin and 2-butanone. Acetoin was produced by resting cells of Lactococcus lactisat product yields close to the the oretical maximum. The resting cell buffer was tailored to meet the requirements of an ensuing electrocatalytic reduction, transforming biotechnologically produced acetoin into 2-butanone. Concluding, the bioprocesses for the biotechnological production of methyl ketoneswere developed and improved in a holistic manner. Biotechnological methods were integrated into the preceding and consecutive process steps and optimized beyond their isolated figures of merit. LB - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3 DO - DOI:10.18154/RWTH-2024-05867 UR - https://publications.rwth-aachen.de/record/987836 ER -