Fig. 7: MSBC enabled phototrophic community assembly.

a Schematic shows that the MSBC can be phototrophic. MSB_phototroph containing the sucrose-secreting S. elongatus convert the carbon dioxide into organic carbon and sustain the growth of MSB_heterotroph. b Generation of MSB(S. elongatus). We encapsulated the S. elongatus with polymeric capsules made of alginate. The growth of the cyanobacteria turned the MSB(S. elongatus) into an enhanced green color. c MSB(S. elongatus) produced sucrose under the osmotic stress induced by sodium chloride. The MSB(S. elongatus) were cultured in BG-11 medium and stressed by supplementing 150 mM NaCl. The yield of sucrose was measured by a sucrose quantification kit (see “Methods”). Error bars = standard deviation (n = 3 biologically independent samples). d Engineered E. coli grew by using sucrose as a carbon source. E. coli were engineered to carry the essential sucrose metabolism genes. The resultant strain utilized sucrose as a carbon source for growth. e Assembly of phototrophic MSBC with a low seeding density of MSB_phototroph. When the seeding ratio of MSB_phototroph and MSB_heterotroph equals 2:1, the low density of MSB_phototroph only supported the limited growth of the MSB_heterotroph. f Assembly of phototrophic MSBC with a high seeding density of MSB_phototroph. When seeding ratio of MSB_phototroph and MSB_heterotroph equals 50:1, the high density of MSB_phototroph better supported the growth of the MSB_heterotroph, as shown by the increased density of the E. coli colonies inside the MSB. Scale bar = 150 μm. Source data are provided as a Source Data file.