In a groundbreaking study, researchers Jimreeves David and Shashi Thutupalli from the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany, have uncovered a novel mechanism by which non-motile microorganisms can rapidly disperse and colonize new environments. Their findings, published in the journal Nature Physics, challenge the long-held assumption that the spread of such microbes is limited by diffusion alone.
The researchers observed that as non-motile yeast and bacteria metabolize dense nutrients into lighter waste products, they generate buoyancy-driven flows in their fluid environment. This phenomenon, known as Rayleigh-Bénard convection, is a well-known fluid-dynamical process that occurs on scales ranging from chemical reactors to planetary atmospheres. The convective flows created by the microbes’ metabolic activity fragment and disperse cellular aggregates, which then seed new growth sites. This, in turn, enhances the microbes’ total metabolic activity and strengthens the convective flow, creating a self-amplifying, autocatalytic cycle.
The expansion of the microbial colonies follows an accelerating power-law kinetics, which the researchers were able to quantitatively capture using a physical theory that links metabolic flux to flow velocity. Additionally, the process produces fractal patterns through a flow-focusing instability that the researchers term “Circulation-Driven Aggregation,” a hydrodynamic analogue of Diffusion-Limited Aggregation.
The practical implications of this research for the energy sector are significant. Understanding and harnessing this “metabolic fireworks” mechanism could lead to more efficient bioreactors for biofuel production, as well as improved strategies for managing microbial growth and dispersal in various industrial settings. Furthermore, the study provides a fundamental, physics-based dispersal strategy that could inform the development of new bio-inspired technologies for fluid transport and mixing.
In summary, David and Thutupalli’s work sheds new light on the remarkable ways in which microorganisms can interact with their environment to overcome constraints and colonize new territories. By revealing the underlying physics of this process, the researchers have opened up new avenues for exploration and innovation in the energy sector and beyond.
Source: David, J., & Thutupalli, S. (2021). Explosive dispersal of non-motile microbes through metabolic buoyancy. Nature Physics.
This article is based on research available at arXiv.