Tiny Bacteria can Fix a Grand Problem

Dr. Swayamdipta Bhaduri, University of Alberta

S. Bhaduri was also a 3MT presentation finalist in 2017. Watch his presentation here.

Global warming is a major problem. It causes melting of the polar ice caps, a rise in sea levels, and a loss of biodiversity [1]. This makes it one of the grand challenges for scientists and engineers.

We know now that the main culprits behind global warming are greenhouse gases like carbon dioxide [2]. One idea to mitigate global warming is by capturing large volumes of these gases from the atmosphere and storing them elsewhere.

This process starts by selecting a proper storage location. Feasible options include abandoned mines, underground geologic structures, or any natural reservoir with enough void space inside [3]. An example is shown in figure (a) to the left.

 (a) An Underground Carbon Reservoir, (b) Icing on a Cake.

(a) An Underground Carbon Reservoir, (b) Icing on a Cake.

This idea looks good except for the fact that all of these natural structures are inherently porous. That means the gases, which are typically stored under high pressures, will have a tendency to leak and escape through the network of micro-scale pores all around. Therefore, for this technique to work properly, one must ensure a reliable sealing strategy.

The good news lies with the tiny little bacteria I work with. This species is named Sporosarcina pasteurii. Given the right chemical environment, these bacteria can produce special particles. These particles, which are essentially small solid crystals, can enter the network of pores like a powder and cause long-range clogging. As a result, the mechanical strength of the structures increases dramatically.

This concept is not much different from icing a cake. One pours the cream on top that trickles down and fills up the voids. Figure (b) on the right shows a similar visual. This is what I do using nanotechnology.

In case you’re wondering what nanotechnology is, imagine the width of a single human hair. Now shrink that by one hundred thousand times. That’s about one nanometer. My technology works at this length scale, hence the name nanotechnology.

Using state-of-the-art ultra-high precision tools, I’m building nanofluidic chips, which are small handheld platforms that very accurately mimic the real underground porous media. By injecting my bacteria inside these chips and using advanced microscopy, I can observe the actual motions inside the pores and the clogging process in real time. These experiments give me key insights into the physical, chemical, and biological aspects of this phenomenon.

Armed with this knowledge, I’m designing robust microbe-based sealing strategies that are clean, green, and cost-effective. With my technology, I hope to transform the dream of safe, long-term underground storage of carbon inside natural reservoirs into a reality in the near future. This, in turn, can help mitigate global warming and make planet Earth a better place to live!

References

[1] Houghton JT, Callander BA, Varney SK, editors. Climate change 1992. Cambridge University Press; 1992 May 28. Available from: http://dx.doi.org/10.1007/978-1-4757-2161-4

[2] Lashof DA, Ahuja DR. Relative contributions of greenhouse gas emissions to global warming. Nature. 1990 Apr; 344(6266): 529. Available from: 10.1038/344529a0

[3] Benson SM, Orr FM. Carbon dioxide capture and storage. Mrs Bulletin. 2008 Apr; 33(4): 303-5. Available from: https://doi.org/10.1557/mrs2008.63