Simulated microgravity enhances intracellular energy metabolism and electricity generation by electrochemically active bacteria for in situ space bioenergy production

Electrochemically active bacteria (EAB) characterized by extracellular respiration is promising for bioregenerative life support systems and elemental cycling at extraterrestrial planetary bases. However, it remains unclear how microgravity modulates genes related to electricity generation and reshapes intracellular energy metabolism. In this study, the impact of simulated microgravity on EAB was systematically analyzed through electricity generation, gene enrichment, energy metabolism, and central carbon metabolic reprogramming. The results demonstrate that simulated microgravity increases the biomass and enriched energy-metabolism genes in mixed-culture EAB to boost electricity generation, while the microbial community does not change. The promoting effect of simulated microgravity on electricity generation also applies to pure-culture EAB. Simulated microgravity reprogrammed intracellular energy metabolism pathways, increased energy metabolism, accelerated NADH hydrolysis, and provided more electrons for electricity generation. This work provides new insights to understand the effects of simulated microgravity on EAB and supports in situ space bioenergy production, exploration of extraterrestrial life, and space biomanufacturing.