Related Experiment Video
Updated: Jun 12, 2026

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System
Published on: August 23, 2024
Imperfect asymmetry of life: earth microbial communities prefer D-lactate but can use L-lactate also
Faegheh Moazeni1, Gaosen Zhang, Henry J Sun
1Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, Nevada 89119, USA.
Abstract:
Asymmetrical utilization of chiral compounds has been sought on Mars as evidence for biological activity. This method was recently validated in glucose. Earth organisms utilize D-glucose, not L-glucose, a perfect asymmetry. In this study, we tested the method in lactate and found utilization of both enantiomers. Soil-, sediment-, and lake-borne microbial communities prefer D-lactate but can consume L-lactate if given extra time to acclimate. This situation is termed imperfect asymmetry. Future life-detection mission investigators need to be aware of imperfect asymmetry so as not to miss relatively subtle signs of life.
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