Impact of low-dose X-ray radiation on the lipidome of Chlorella vulgaris

C. vulgaris is a microalga with great potential as a source of lipids and essential fatty acids for human nutrition during extended space missions to Mars. However, the effects of Mars-like radiation on lipid composition are still poorly understood. In this study, we analyzed the effects of X-rays on the growth and lipid biosynthesis of C. vulgaris CCALA 269, exposing the cultures to doses of 450, 900, 1800, 3600, and 10,800 mSv, simulating approximately 354, 709, 1417, 2835, and 8504 days of exposure to Martian radiation, respectively. The results show that, although growth remained stable, doses exceeding 1800 mSv led to an increased production of specific lipid classes, suggesting an adaptive mechanism to counteract radiation stress. This adaptation was accompanied by an increase in reactive oxygen species (ROS) and changes in pigment composition, with an elevation in pheophytin-a and chlorophyll-a, and a decrease in chlorophyll-b. Our results demonstrate the ability of C. vulgaris to adapt to ionizing radiation, highlighting its suitability for sustainable lipid production in extraterrestrial environments, supporting human life on Mars through in situ resource utilization. • C. vulgaris was exposed to X-ray doses simulating the ones occurring during missions to Mars. • No significant effect was observed on the growth rate of the strain at different doses. • Chlorophyll-a and pheophytin-a, increased with the dose while chlorophyll-b decreased. • Saturated and Polyunsaturated Fatty Acids increased at low irradiation doses. • In general, hormetic effect was observed for different lipid classes useful for crew nutrition.