Steering chemical productivity of cooperative photobiocatalytic consortia by material-assisted light and mass transport within biofilms

• Applicants: Dr. Mahir Bozan; Professor Dr. Tilo Pompe
• Subject Area: Biological Process Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559375699

Multi-species biofilms exhibit promising properties for photobiotechnology in chemical production. However, biofilm systems encounter technological challenges in terms of light, nutrition, and product transport within the dense biofilm layers. These problems lead to limited industrial applications. This project addresses these challenges as it aims to understand and steer light and mass transport within photobiocatalytic multi-species biofilms for increased chemical production. We will engineer hydrogel scaffolds that adapt features of the natural biofilm matrix to guide both light and mass within deep biofilm layers. 3D porous hydrogel scaffolds based on poly(acrylamide) will be synthesized with adjusted pore size, crosslinking degree, elasticity, and surface functionalization and will be characterized by their light and molecular transport characteristics. Furthermore, we will design microbial consortia with extended spectral light harvesting and cooperative biocatalytic reactions. The consortia will consist of genetically engineered photoautotroph Synechocystis sp., wild-type chemolithotroph Rhodopseudomonas palustris, and chemoheterotroph Pseudomonas taiwanensis, each contributing unique metabolic and technological functions. With our approach of material-assisted multi-species biofilm consortia, we will steer the biocatalytic performance of the system for high productivity. We will spatiotemporally analyze how the different cooperative microbial species adjust their metabolic interaction within the material-assisted biofilm. We will examplify the photobiocatalytic productivity of the biofilm system using the synthesis of 6-hydroxyhexanoic acid from cyclohexanone, a key precursor for industrial poly(caprolactone) synthesis. Overall, our strategy will target a higher chemical biofilm productivity. The material-assisted steering of biofilm architecture and metabolic interactions of the cooperative species will allow for this improved productivity. Furthermore, we aim to support a better understanding of the adaption of multiple bio-catalytically active species concerning their spatiotemporal localization and metabolic activity, also by developing and using new quantitative analytical tools of the bio-catalysis of multi-species biofilms. Achieving these goals will allow us to push current knowledge and standards in productive biofilms by providing new model systems of multi-species biocatalytic biofilms and deeper insights into light and mass transport principles in biofilms.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2494: Productive Biofilm Systems