Effect of Isomorphous Substitution in ZSM-5 in Tandem with ZnO-ZrO2 for Direct Conversion of CO2 to Aromatics

Cell-cell adhesion is central to the design of novel biomaterials and other multicellular technologies. However, adhesion can decrease fitness, as aggregation alters the nutrient fluxes and physical forces experienced by the cell, thereby reducing the overall growth rate and limiting cell division. Creating robust multicellular assemblies therefore requires a deeper understanding of the effects of adhesion on fitness. To identify key factors that promote and stabilize multicellularity, we first studied aggregation in wild strains of Saccharomyces cerevisiae and then applied these principles to the bottom-up construction of synthetic yeast aggregates. We found that the wild strains ranged from single cells to macroscopic aggregates and formed larger groups in less rich media. Over two weeks of growth in diverse selection conditions, large aggregates reverted to smaller sizes while some unicellular yeast started to form groups. Though these effects varied with genotype, size changes were largely mediated by dilution factor, with longer times at saturation producing larger aggregates and vice versa. Together, these results suggest that aggregation is part of an adaptive response to nutrient availability. We therefore hypothesized that synthetic aggregates could be stabilized by careful control of media conditions or reprogramming their environmental response. Using an automated continuous culture platform, we showed that engineered yeast expressing a single adhesion gene were sensitive to dilution during growth, phenocopying what we observed in wild strains, and identified growth conditions that preserved aggregate size. We also explored strategies to stabilize aggregates by manipulating metabolic genes to encourage cross-feeding. Together, these results lay the groundwork for identifying key design principles for the stable formation of cell aggregates, which is central to the design of robust biomaterials.