Engineered Living Materials for Bioproduction Downstream Processing

De novo engineered living materials (ELMs) are cellular systems that self-assemble into macroscopic structures through genetically encoded interactions, offering a route to programmable materials grown directly from living cells. Despite their promise, the molecular design principles that enable scalable self-assembly in de novo ELMs remain poorly understood. Here, we engineer Escherichia coli to display elastin-like polypeptides (ELPs) on the outer membrane, transforming single cells into self-assembling living materials through weak intermolecular interactions. By tuning the polarity of ELP sequences, we generate assemblies spanning micrometer- to centimeter-length scales that sediment within a few hours while preserving cellular metabolic activity. We demonstrate the portability of this platform across genetic backgrounds and inducible expression systems, and deploy it in an ethanologenic E. coli strain as a proof of principle. In small-scale fermentation settings, ELP-based ELMs enable controllable flocculation, reduce filtration time by more than threefold, and maintain ethanol production performance comparable to that of the parental strain. Together, this work establishes ELP surface display as a modular strategy for constructing de novo engineered living materials and defines initial genetic design rules linking molecular-scale interactions to emergent macroscopic organization.