Microbial Autotrophy via Direct Uptake of Extracellular Electrons from Liquid-Solid Triboelectrification

Energy is fundamental to all terrestrial life, including microorganisms, which currently rely primarily on chemical and light energy. The triboelectric effect, a ubiquitous phenomenon resulting from interfacial charge transfer during contact-separation of materials, is hypothesized to efficiently convert mechanical energy into electricity. Here, we demonstrate that liquid-solid friction can convert mechanical energy into electrical energy, thereby supporting autotrophic microbial growth and metabolism without relying on conventional sunlight or chemical energy inputs. Using electroactive Rhodopseudomonas palustris and dielectric poly(vinylidene fluoride) (PVDF) as a model biohybrid system, we found that mechanical vibration primarily induces triboelectric charge transfer at the water-PVDF interface, leading to free electron accumulation on the PVDF surface. These electrons are subsequently taken up by R. palustris for carbon fixation and denitrification, resulting in an increase in biomass from ca. 2.79 ± 0.25 to 6.27 ± 0.31 mg of protein/L over 30 days. This phenomenon was further observed across various dielectric materials and electroactive bacterial strains, suggesting a potentially universal mechanical-force-driven process for microbial communities. Our findings reveal a novel role of mechanical force via the triboelectric effect as an energy source for driving microbial growth and metabolism, which enhances our understanding of the interactions between mechanical forces and biological systems.