Fig. 7. Optimization of the bio-ISRU for 2,3-BDO production.

a Biological optimization of the bio-ISRU. Payload mass, power requirement, and water use can be reduced by optimizing: Left: cyanobacteria growth productivity, Center: the enzymatic digester glucose yield, and Right: 2,3-BDO fermentation yield from glucose. Solid vertical lines are the productivity and yields of the bio-ISRU for 2,3-BDO production using state-of-the-art technology. Dashed vertical lines are the productivity and yields of the biologically optimized bio-ISRU. b Materials optimization of the bio-ISRU. Payload mass changes when switching the material used for the biofilm substrate, from cotton to low-density polypropylene (LDPE), and the reactors, from steel to high-density propylene (HDPE). c Summary of payload mass and power requirement reduction of the biofilm-based bio-ISRU for 2,3-BDO as it is optimized. The DRA 5.0 O₂ only strategy is the mass of shipping CH₄ from Earth and using SOCE to produce O₂ from Martian CO₂ (ref. ²). Source data are provided as a Source Data file.