Project Details
Projekt
Resource-Saving Biofilm Reactors for Aerosol Biotransformations
Subject Area
Biological Process Engineering
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 559141727
The project ReActoB will look at two major aspects of biofilm-based bioprocess development, novel, scalable biofilm reactor designs and biofilm control, thus, addressing topics 3 and 1 of the call, respectively, aiming to deliver blueprints for future developments. To enable the resource-saving operation of biofilm-driven biotransformation reactions, a novel biofilm reactor for aerosol biotransformations (BRAB) and means to control biofilm growth via optogenetic tools will be developed. Reactor development will be based on an existing biofilm reactor technology originally developed to cultivate terrestrial cyanobacteria for biomass production. In ReActoB, this system will be expanded to enable biofilm growth of both chemohetero- and photoautotrophic microorganisms of both aquatic and terrestrial origin as well as their use for biotransformation reactions including in situ product removal (ISPR). The key concept of the BRAB is the supply of growth medium as an aerosol, which significantly reduces the medium demand in continuous bioprocessing. A high surface area for biofilm attachment and medium and biotransformation substrate supply via the gas phase will be in focus. The challenging biotransformation of cyclohexane to cyclohexanol will be investigated as a model reaction. To this end, we will evaluate biofilm performance in the BRAB using recombinant variants of Pseudomonas taiwanensis VLB120 and Synechocystis sp. PCC6803 in axenic as well as in mixed cultures. ISPR is aimed at via extractive product recovery using solvent-impregnated resins, which are easier to recover and less solvent-intensive compared to a pure solvent phase. For biofilm investigation and characterization, a comprehensive workflow is established. Evaluation of biofilm architecture and cell patterning from the meso- to the micro-scale will be done using various imaging techniques ranging from optical coherence tomography to helium ion microscopy. Rapid assessment of population dynamics will be conducted via flow cytometry, while the chemical composition of the biofilm will be assessed via chemical analyses and Raman spectroscopy. Furthermore, we want to elucidate, if it is possible to use light-controlled switches for biofilm thickness control. For this purpose, we will first generate an auxotrophic variant of P. taiwanensis VLB120. In the next step, genes resolving the auxotrophy will be placed on a plasmid under the control of an optoswitch from the LOV family. This will enable growth as long as the biofilm is thin enough to allow light penetration, followed by growth arrest once light is not able to sufficiently penetrate the biofilm anymore. With this system, we will investigate if and how growth control can be achieved by adapting light intensity or availability. This will open the door to a new way for the regulation of biofilm functions.
DFG Programme
Priority Programmes
Subproject of
SPP 2494:
Productive Biofilm Systems
