Oxygen is essential for most living organisms, fueling cellular processes by acting as the final electron acceptor in the chain of reactions that convert nutrients into energy. This essential process is called respiration, a mechanism most living creatures depend on to sustain life. However, many microorganisms that help mitigate pollution, recycle nutrients, and influence climate dynamics don’t have the luxury of oxygen. These microbes, often found deep underground or beneath the ocean, have adapted by evolving a remarkable system of “breathing” minerals from their environment. Instead of relying on oxygen, they use specialized structures, called nanowires, to eliminate the excess electrons produced during their metabolic processes.
The scientific community has long known about the complex microbial processes that allow these bacteria to thrive in oxygen-deprived environments. A few years ago, a team of scientists led by Nikhil Malvankar at Yale University’s Microbial Sciences Institute took a step toward understanding one of the most extraordinary features of these bacteria: nanowires. These tiny protein filaments act as organic wires, capable of conducting electrons to and from the surrounding minerals in their environment. These bacterial nanowires have vast potential not only in understanding the functioning of these microbes but also in real-world applications—such as cleaning pollutants, producing energy, and controlling atmospheric gases contributing to climate change, like methane.
Malvankar’s team had previously identified that bacterial nanowires are made up of a chain of heme molecules, which share similarities with hemoglobin in human blood, both of which are essential for moving electrons in the environment. Hemoglobin is critical for oxygen transport, while bacterial heme nanowires serve to move electrons when the organism “breathes” through minerals. Although this breakthrough was a critical first step, one of the major questions remained unsolved: How exactly do these heme proteins assemble into functional nanowires?
In a new development, a research team led by Cong Shen, a member of the same lab at Yale, has made a critical discovery. Their study has revealed the specific machinery that bacteria use to assemble these intricate nanowires. This finding could significantly unlock potential practical applications of these microbial systems. Their research, published in the journal Cell Chemical Biology, further describes how the bacteria’s genetic machinery can be tweaked to increase the production of these electron-transporting filaments, leading to accelerated bacterial growth and faster nanowire formation.
The Power of Nanowires in Nature
The phenomenon of microbes “breathing” minerals is particularly intriguing in terms of its ecological impact. Many of these microorganisms, such as Geobacter sulfurreducens and Shewanella oneidensis, thrive in environments devoid of oxygen, including deep oceanic sediments or polluted soils. These bacteria play a crucial role in breaking down organic matter and minimizing environmental damage, such as excess pollution and carbon accumulation. The nanowires are essential to this process, allowing the bacteria to exchange electrons with minerals in the surrounding soil, which in turn aids in the remediation of contaminated environments.
The assembly of nanowires involves a process that, while inherently biological, is comparable to processes in human-made technology. These bacteria can generate energy by essentially “wiring” themselves to electrodes or buried minerals. If researchers can understand how bacteria make these connections and tweak the process, it opens the door to bioengineering microbes that can be used in bioremediation, bioenergy production, and environmental sustainability efforts, which are vital in the fight against climate change.
Discovering the Machinery Behind Nanowire Formation
The discovery that the machinery capable of producing nanowires could be engineered for improved performance comes from an in-depth analysis conducted by the team under Shen’s direction. According to their research, among the 111 known heme proteins, only three are responsible for polymerizing and forming the nanowires in these bacteria. These three proteins work in concert, each playing a specific role in assembling the nanowires with remarkable precision. Without this unique molecular machinery, the process of constructing a functional nanowire would be impossible.
Through careful experimentation, Shen’s team was able to identify the crucial steps involved in the polymerization of these heme proteins. The researchers were also able to demonstrate how changes in the proteins’ surrounding machinery could lead to more efficient nanowire formation. Altering specific components in the process—such as varying the protein expression or introducing gene modifications—could potentially lead to accelerated reproduction of these nanowires, which would subsequently promote faster bacterial growth.
This breakthrough is important for many reasons. Primarily, understanding and manipulating nanowire formation could make it feasible to harness the unique properties of these bacteria for practical applications. For instance, enhanced nanowire production could enable bacteria to more effectively transfer electrons and produce usable energy. Further, it could provide valuable insights for environmental cleanup, where such microbes could be used to neutralize pollutants in water, soils, or even in the air.
The Potential of Nanowires in Biotechnology
The implications of these discoveries reach well beyond a fundamental understanding of microbial behavior. The capacity of nanowires to conduct electrons could be invaluable in several biotechnological fields, from energy production to pollution control.
Bioremediation: Nanowires could play a critical role in cleaning pollutants from the environment. Bacteria with enhanced nanowires could be engineered to “eat” or neutralize toxic chemicals in contaminated environments. They could also help restore ecosystems degraded by industrial pollution, providing a much-needed method of biological cleanup.
Bioelectricity Production: These microbial nanowires have been studied as potential catalysts for generating bioelectricity. The ability of these bacteria to transport electrons directly through solid matter enables the production of electricity from waste products. Bacteria may one day power small devices or contribute to large-scale bioelectricity production systems that harness microbial processes.
Mitigating Climate Change: Another pressing application is addressing the issue of atmospheric methane. Methane is a potent greenhouse gas that contributes to global warming, and controlling methane levels is a priority in climate science. Nanowire-forming bacteria that consume methane could reduce its presence in the atmosphere. By enhancing the efficiency of these microbes, scientists could develop bioengineered systems to mitigate methane emissions effectively.
Energy Storage: In a world increasingly reliant on sustainable energy sources, energy storage becomes a significant hurdle. Nanowires could one day be used in bioelectronic devices designed to store energy, helping us transition away from reliance on traditional fossil fuels.
Accelerating Nanowire Production for Future Technologies
The development of machinery capable of boosting bacterial nanowire production is one step closer to realizing the practical potential of these microorganisms. The discovery by Shen and his colleagues provides a promising platform for advancing the use of microbes as biological machines. By modifying genetic circuits or manipulating bacterial gene expression, scientists might control the production rates of nanowires and subsequently optimize the capabilities of these bacteria.
As synthetic biology and bioengineering advance, understanding how to guide these tiny microorganisms could be pivotal. The research could lead to future industrial applications, where bacteria are utilized to tackle large-scale environmental challenges like pollution, waste management, and climate change.
Conclusion: A New Era in Microbial Biotechnology
The research by Cong Shen and his team provides not only a fascinating glimpse into the molecular intricacies of nanowire production but also highlights the increasing potential of microbes as environmental agents and biotechnological tools. As microbial sciences progress, understanding and manipulating the components of microbial “breathing” could open a wide range of opportunities in sustainable technology, climate change mitigation, and renewable energy. The key discoveries emerging from this research offer a path toward a more sustainable future, showing how biological innovation may lead the way in combating the planet’s most pressing challenges.
From cleaning polluted environments to harnessing the power of bacteria for clean energy, microbial nanowires exemplify the growing convergence between nature’s ingenuity and human innovation. The next step is to apply these findings practically, creating bioengineering solutions that can transform how we address the global environmental crisis and move toward a cleaner, more sustainable future.
Reference: Cong Shen et al, A widespread and ancient bacterial machinery assembles cytochrome OmcS nanowires essential for extracellular electron transfer, Cell Chemical Biology (2025). DOI: 10.1016/j.chembiol.2024.12.013
