No Effect of Microgravity and Simulated Mars Gravity on Final Bacterial Cell Concentrations on the International Space Station: Applications to Space Bioproduction

Research output: Contribution to journalArticlepeer-review


  • Rosa Santomartino
  • Annemiek C. Waajen
  • Wessel de Wit
  • Luca Parmitano
  • Claire-Marie Loudon
  • Ralf Moeller
  • Petra Rettberg
  • Felix Fuchs
  • Kai Finster
  • Jutta Krause
  • Andrea Koehler
  • Nicol Caplin
  • Lobke Zuijderduijn
  • Valfredo Zolesi
  • Michele Balsamo
  • Alessandro Mariani
  • Stefano S. Pellari
  • Fabrizio Carubia
  • Giacomo Luciani
  • Jeannine Doswald-Winkler
  • Magdalena Herova
  • Jennifer Wadsworth
  • Craig R. Everroad
  • Bernd Rattenbacher
  • René Demets
  • Charles S. Cockell

Institutes & Expert groups

  • University of Edinburgh - UK Centre for Astrobiology
  • ESTEC - European Space Research and technology Center - ESA
  • DLR - German Aerospace Center
  • Aarhus University
  • Kayser Italia S.r.l., Italy
  • BIOTESC - Biotechnology Space Support Center, Hochschule Luzern Technik und Architektur
  • NASA - Ames Research Center

Documents & links


Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experiment on the International Space Station to study microbe-mineral interactions in microgravity, simulated Mars gravity and simulated Earth gravity, as well as in ground gravity controls, with three bacterial species: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metallidurans. To our knowledge, this was the first experiment to study simulated Martian gravity on bacteria using a space platform. Here, we tested the hypothesis that different gravity regimens can influence the final cell concentrations achieved after a multi-week period in space. Despite the different sedimentation rates predicted, we found no significant differences in final cell counts and optical densities between the three gravity regimens on the ISS. This suggests that possible gravity-related effects on bacterial growth were overcome by the end of the experiment. The results indicate that microbial-supported bioproduction and life support systems can be effectively performed in space (e.g., Mars), as on Earth.


Original languageEnglish
Article number579156
Pages (from-to)1-15
Number of pages15
JournalFrontiers in Microbiology
Publication statusPublished - 14 Oct 2020


  • Microgravity, Spaceflight, Mars gravity, BioRock, International Space Station, ISS, Space microbiology, Space bioproduction, Bacterial cell concentration

ID: 6978604