Fig. 5. Resolving oxygen contradiction by combining conductive hydrogel with aerobic respiration-null mutants.

a Schematic illustration of conductive hydrogel-based system. Three heterotrophic microorganisms (E + S + G) were encapsulated in a conductive hydrogel, in which a relatively anaerobic environment could be formed. To avoid the escaped cells dissipating electrons through aerobic respiration, the aerobic respiration chains of heterotrophic microorganisms were blocked. b Electricity generated by encapsulated S. oneidensis in PPy conductive hydrogel. Control groups without electron donor, without S. oneidensis, or without conductive hydrogel were included for comparison. c The fermentation of sucrose to lactate by the engineered E. coli strains E2 and E3 under anaerobic and aerobic conditions. Strain E3 is an aerobic respiration-null mutant. Data are presented as mean values ± SD from n = 3 independent experiments. d Drop plate test showing the growth defect of an aerobic respiration-null mutant of S. oneidensis (S3) under aerobic conditions. Source data are provided as a Source Data file.