Microgravity Effect on Bacterial Growth: Further Clarification of the Underlying Mechanism

Gravity interacts with other physical environmental factors to impact the formation of today's Earth and contribute to biological variations between water and land species. Microbes, with their simple structures and small sizes, are expected to be less gravity-sensitive than larger species. However, microgravity can greatly impact the mass transfer and interface behavior in the extracellular environment, and various effects of spaceflight on bacterial growth have been observed. Our earlier literature review summarizes the systematic efforts to understand the spaceflight effect on microbial growth through the extracellular mass transfer mechanism and provides an in-depth literature review to address some discrepancies observed in the literature. This paper analyzes the effects of microgravity on the extracellular environment, and their potential effect on bacterial growth, to further clarify the underlying mechanism of the microgravity effect on bacterial growth.