Engineered Bacterial Coacervates

• Applicant: Daniele Di Iorio, Ph.D.
• Subject Area: Biomaterials ; Biological and Biomimetic Chemistry
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 520634207

This proposal aims at establishing a new type of engineered living material (ELM) that will take the name of ´engineered bacterial coacervates´ (EBCs). The formation and characterization of such newly developed materials will be the main focus of the presented project. EBCs will consist of coacervates that, upon liquid-liquid phase separation, will encapsulate engineered living bacteria. The combination of coacervates with engineered bacteria will lead to a new class of versatile ´living-in-synthetic´ employable for a wide range of applications. One on hand, the coacervates will function as cages for bacteria, preserving their function and viability. On the other hand, the encapsulated engineered living bacteria will provide the protocells with unique ´on demand´ properties that can be finely tuned by specific bacteria engineering. This approach provides several strong advantages. The presence of engineered bacteria allows for the production of metabolites that would require complex enzymatic pathways, thus elevating the level of complexity of reported artificial cells. Metabolites produced by engineered bacteria can be in-situ transformed in coacervates by secondary encapsulated enzymes and successfully released into the external environment. Here, two approaches will be investigated for the investigation of EBCs consisting in (i) the in situ formation of coacervates in a solution containing engineered bacteria and (ii) the use of engineered bacteria as nucleation centers for the formation of coacervates. The integration of top-down engineered components in bottom-up synthetic cells such as coacervates will represent a novel way to improve the complexity and functionality of innovative hybrid materials. The developed EBCs will be characterized in order to assess the survival conditions of bacteria and to explore their use in non-conventional media or materials. Finally, proof of principle experiments will be carried out to prove the activity of bacterial coacervates and their ´on-demand´ production of metabolites as well as the responsiveness to external stimuli. Possible developments can be seen in the adaptive and auto-regulatory behavior of the materials, in which coacervates and bacteria can influence each other’s properties, based on external stimuli. Overall, the development of EBCs with this work will lay the groundwork for the employment of such materials in multiple future applications.

• DFG Programme: Research Grants