Abstract

The successful implementation of many biotechnological processes in conventional reactors is hindered by toxicity of substrates or products, despite theoretically high production rates. To overcome the limitations, strain and process engineering can work together on integrated reaction and separation techniques. A possible method is in situ liquid-liquid extraction, adding a second liquid organic phase, in which detrimental components can accumulate, while their concentration is lowered in the aqueous phase. Multiphase reactor concepts developed for this purpose usually feature a stirred compartment in which a stirrer breaks up bubbles and droplets. The finely dispersed droplets cause emulsions that are difficult to separate. This leads to reduced efficiency due to the loss of valuable biomass and products included in the emulsions. Within MK-ScaLoop we are addressing this challenge with the novel Multiphase Loop Reactor (MPLR, Figure 1). In this reactor, aeration and extraction are carried out in separate compartments, the riser and the downcomer. The lower turbulence in the downcomer compartment results in droplet sizes that coalesce more easily and can thus be withdrawn as a coherent phase. Within MK-ScaLoop we will develop and transfer the concept of the MPLR, which has already been operated at bench-scale (5 L), to a biotechnological process in respect to environmental and economic aspects. The MPLR is benchmarked against stirred multiphase reactors with one compartment, highlighting the potential of the MPLR. By means of the MPLR, the microbial production of methyl ketones (MK) with a chain length from C11 to C17 will be enabled. MK represent a group of highly reduced platform chemicals that are currently industrially produced from petroleum-based hydrocarbons. They are used in the fragrance, flavor, pharmacological and agrochemical industries and are also discussed as biodiesel blends. To produce MK, the genetically modified production strain Pseudomonas taiwanensis VLB120 is the whole-cell biocatalyst with the best product yield to date. Therefore, the organism will be further genetically adapted for use and conditions in the MPLR. Similarly, the reactor will be fluid dynamically characterized and adapted for beneficial fermentation and phase separation in abiotic scale-up (100 L). A numerical reactor model parameterized with characteristic numbers derived from the fluid dynamical experiments predicts technical scale conditions. These conditions are experimentally replicated and examined at small scale (scale-down approach). Considering (regional) market conditions, the integration of an overall process chain from substrate supply to product market access is evaluated, assuming industrial scale production (>10.000 t/a). This will be analyzed in terms of environmental and economic impacts by means of life cycle costing (LCC) and life cycle assessment (LCA), including the data availability-dependent comparisons to conventional MK production. The process within MK-ScaLoop is also the exemplary foundation to continuously develop prospective LCA methods for biotechnological processes in general.

BOOST FUND 2.0 Coordinator

Diana Wall
AVT.FVT - Fluid Process Engineering
RWTH Aachen

Partners

Prof. Dr. Andreas Jupke & Diana Wall, AVT.FVT - Fluid Process Engineering, RWTH Aachen
Prof. Dr. Lars Blank & Dr. Till Tiso, iAMB - Institute of Applied Microbiology, RWTH Aachen
Dr. Wilhelm Kuckshinrichs & Dr. Petra Zapp, IEK-STE - Systems Engineering and Technology Evaluation, Forschungszentrum Jülich

Fuding Period

01.07.2022 - 30.06.2025

Funding

MK-ScaLoop is part of the NRW-Strategieprojekt BioSC and thus funded by the Ministry of Culture and Science of the German State of North Rhine-Westphalia.

Publications

Ziegler, AL, Grütering, C, Poduschnick, L, Mitsos, A and Blank, LM (2023). Co-feeding enhances the yield of methyl ketones. J Ind Microbiol Biotechnol 50(1).