Engineered Living Materials for Bioproduction Downstream Processing

Microbial fermentation provides a renewable route to a wide portfolio of fuels, chemicals, and therapeutics, yet product recovery is still dominated by energy-intensive biomass-removal operations. Here, we engineered Escherichia coli to display elastin-like polypeptides on its outer membrane, transforming single cells into flocculating E. coli -based engineered living materials (FloEc-ELMs). These self-assembling aggregates span from micrometer to centimeter scale, sediment within two hours, and do not compromise the ethanol-production capacity of an industrial ethanologenic strain. When deployed in bench-scale lactose fermentations, FloEc-ELMs reduced filtration time 3.2-fold, while preserving an ethanol yield comparable to the non-engineered parental strain. By mapping ELP sequence polarity to toxicity and aggregate size, and by porting the system across genetic backgrounds and inducible promoters, we provide design rules for modular, portable ELM-mediated flocculation that can streamline downstream processing in large-scale biomanufacturing.