Fig. 8: Effects of increasing founder population sizes on droplet growth outcomes.

Simulated P. veronii relative biomass abundance (a) and variance (b) in droplet growth (n = 500 droplets, 3 replicate simulations, bars show the mean; Violin plot overlays show median, 25th and 75th percentiles) with increasing founder population sizes of both P. veronii and P. putida in proportionally increased droplet volumes (hence, same starting cell density). Two starting conditions: Poisson-sampled or constant cell numbers. Inset shows the proportion of P. veronii-dominated droplets (i.e., relative biomass > 0.5). P-values from two-sided Kruskal-Wallis rank sum test. c Total P. veronii relative biomass abundance compared to P. putida from solo and mix simulated droplets in (a). Bars show the mean overlaid with individual data points. P-values from ANOVA testing. d–f Simulations as in (a–c) but with constant droplet volume and increasing founder population sizes (hence: increasing starting cell densities). g Experimental strategy to achieve increasing founder cell population sizes and densities. OD, starting culture turbidities. PPU, P. putida; PVE, P. veronii. h Measured relative biomass of P. veronii (as the proportion of the P. veronii median-normalized AF signal compared to the sum median-normalized productivity per droplet of both P. veronii and P. putida) after 24 h incubation in the different droplet starting conditions (data points pooled from n = 3 replicate emulsions). i Decreasing variance in observed P. veronii-relative abundance at higher founder population sizes. P-values from non-parametric variance comparison Fligner test, adjusted by Bon Ferroni correction. j P. veronii stationary phase cell counts (by flow cytometry) as proportion of the sum of P. veronii and P. putida counts, after coalescing droplet emulsions to a single suspension, for the different founder population sizes (n = 3 replicates). Comparison: relative P. veronii cell counts in 96-well co-culture suspensions after 24 h, started with ca. 0.5 million cells per strain per 140 µl (n = 3 biological replicates). Letters indicate statistically significant groups at a p-value < 0.05 from an ANOVA with two-sided HSD Tukey post hoc test. Source data are provided as source data file.