Fig. 1

Axenic characterizations of candidate strains. a This schematic shows the engineered microbial community design. CscB ⁺ S. elongatus (green) capture light and CO₂ via photosynthesis. Fixed carbon is secreted as sucrose (black arrows) when induced with IPTG in the presence of osmotic pressure (NaCl). This secreted carbon then supports the growth of B. subtilis (blue), S. cerevisiae (purple), or E. coli (orange) with the final goal of production of target compounds from those heterotrophs. Axenic cscB ⁺ S. elongatus was grown in ^CoBBG-11 with (solid line) and without IPTG (dashed line) to induce sucrose secretion. Cell density (b) and sucrose levels in culture supernatants (c) were measured. Error bars are standard deviation of 8 biological replicates. For characterization of cyanobacteria in ^CoYBG-11 see Additional file 1: Figure S1. d Heterotroph growth in isolation was characterized via growth rate in co-culture buffer supplemented with 2% sucrose. Error is standard deviation of ≥ 3 replicates