Effects of a novel bioprocess for the cultivation Synechococcus nidulans on Mars on its biochemical composition: focus on the lipidome

In the present work, the possibility to grow the strain Synechococcus nidulans CCALA 188 on Mars using a medium mimicking a one obtainable using in situ available resources, i.e. the so-called Martian medium, under an atmosphere obtainable by pressurization of Mars CO₂, is investigated. The goal is to obtain a biomass with high-value products to sustain a crewed mission to Mars. The results show that the replacement of 40% vol of Z-medium with the same volume of Martian medium does not affect the cultivation and leads to a slight improvement of biomass productivity. Under an atmosphere consisting of pure CO₂ the growth rate was reduced but the strain managed to adapt by modifying its metabolism. Total proteins and carbohydrates were significantly reduced under Mars-like conditions, while lipids increased when using CO₂. A balanced diet rich in antioxidants is crucial for the wealth of astronauts, and in our case, radical scavenging capacities range from 15 to 20 mmol_TEAC/kg were observed. Under CO₂, a reduction in antioxidant power is observed likely due to a decrease in photosynthetic activity. The lipidome consisted of sulfoquinovosyldiacylglycerol, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, phosphatidylcholine, phosphatidylglycerol, and triacylglycerol. A significant increase in the latter ones was observed under Mars simulated atmosphere.