ELASSS April 2023 - Dr Buz Barstow

TITLE: Biomining and Electromicrobial Production

SPEAKER: Dr Buz Bartow, from the Cornell University, Atkinson Center and Carl Sagan Institute (USA)

WHERE: JCMB, Lecture theatre B

WHEN: April 6th, 2023, 2.00pm 

Abstract: 

In this talk I'll discuss two areas of research from my lab: (1) engineering microbes to mine metals for sustainable energy technology and carbon mineralization, and (2) to convert electricity and carbon dioxide into fuels, food, and lixiviants for biomining. 

Creation of a new sustainable energy infrastructure means that the demand for metals is increasingly rapidly, but traditional mining technology won't be able to keep up with demand. Rare earth elements (REE) are essential ingredients in high field magnets for wind turbines and electric vehicles, solid state lighting and superconductors; nickel is essential for catalysts; cobalt for batteries; platinum group elements for electrical contacts and H2-producing catalysts; and magnesium could be essential for carbon mineralization. Demand for REE is projected to increase 7× between now and 2040; the demand for Mg could go up 6,000× by the end of the century. Traditional mining processes can be highly environmentally damaging, and traditional deposits of many metals won't be sufficient to meet the needs of the energy transition.  

Biomining could replace traditional mining with environmentally-friendly bioprocesses. My lab has used our Knockout Sudoku technology to characterize the genome of the mineral-dissolving microbe Gluconobacter oxydans and discover the genetic systems that enable it to mine rare earth elements. We have used this new knowledge to create a roadmap for engineering G. oxydans that has already improved biomining of REE by 73%. On top of this, we have also used Sudoku to understand the genetics behind selective biosorption of REE by Shewanella oneidensis. We have discovered single-gene knockout mutants that adjust the preference of S. oneidensis for light, medium and heavy REE by 1 to 4%. This doesn't sound like a lot, but even these small changes could reduce the length of a repeated enrichment process to achieve 99.9% purity of a single lanthanide by almost 30%. On top of this, this genomic knowledge gives us a roadmap for engineering S. oneidensis to improve this selectivity even further. These advances have allowed us to transfer this technology to a new company called REEgen that specializes in engineering microbes for mining. Finally, we've recently shown that G. oxydans can dissolve silicate minerals, the first step in providing an enormous amount of metals for carbon mineralization. 

Next, even if we can find all of the metals we need to electrify the world economy, we'll still need carbon-neutral fuels and food for a long time. Today, the only way we have to get the carbon and energy for these things is through photosynthesis. However, the efficiency of photosynthesis is incredibly low (< 1% globally). This means that any expansion of photosynthesis creates competition between land for wilderness and agriculture. Electromicrobial production that combines highly flexible microbial metabolism and renewable electricity has already been shown at lab scale to exceed the efficiency of photosynthesis. In the second part of my talk I'll discuss my team's work on figuring out the kinetic and thermodynamic limits on the performance of EMP; just how efficient it could be at making food and jet fuel. Finally, I'll discuss if it possible to use EMP to make the lixiviants needed to provide enough metals to make a serious dent in the CO2 problem.