The image for this blog post is oddly appropriate. It’s about a breakthrough in science which is called “a milestone” by Nature magazine in a recent article. Nature is not exactly a sensationalist journal. So when they say milestone… it is one.
The article’s key paragraph is here:
The achievement is a milestone, say scientists, because it drastically alters the inner workings of one of biology’s most popular model organisms. And in the future, CO2-eating E. coli could be used to make organic carbon molecules that could be used as biofuels or to produce food. Products made in this way would have lower emissions compared with conventional production methods, and could potentially remove the gas from the air.
Normally, E. Coli (officially Escherichia coli) prefers to eat sugars and emits carbon dioxide as a waste product. In other words, it eats here and gets gas. We want the little critters to instead consume carbon dioxide. There are aquatic microbes that transform CO2 into oxygen but these are difficult to genetically modify in quantity so that they could become a “biological factory’ to mass-capture CO2 and produce beneficial outcomes.
E.Coli is actually easy to genetically modify – and it grows quickly, so the engineering changes can be quickly optimized. But it has that sweet tooth habit that’s hard to kick.
The breakthrough that’s taken place here is a switch in diet. The E.Coli can be tricked into eating CO2 for their source of carbon rather than eating sugars and er… gassing out… CO2.
Paraphrasing the article:
Ron Milo and his team at the Weizmann Institute in Israel used a mix of genetic engineering and lab evolution to create a strain of E. coli that can get all its carbon from CO2. To trick the E.Coli, , they gave the bacterium genes that encode a pair of enzymes that allow photosynthetic organisms to convert CO2 into organic carbon.
To overcome the fact that E.Coli does not have any means to use light to process the CO2 into organic carbon, they inserted a gene that lets the bacterium glean energy from an organic molecule called formate.
But that wasn’t enough. The E.Coli still wouldn’t go for the CO2 meal. The project team had to persist.
To further tweak the strain, the researchers cultured successive generations of the modified E. coli for a year, giving them only minute quantities of sugar, and CO2 at concentrations about 250 times those in Earth’s atmosphere. They hoped that the bacteria would evolve mutations to adapt to this new diet. After about 200 days, the first cells capable of using CO2 as their only carbon source emerged. And after 300 days, these bacteria grew faster in the lab conditions than did those that could not consume CO2.
Isn’t that interesting? It’s almost like breeding dogs for certain behaviors, as we did with shepherds to modify their hunting instincts into one that stalks but does not kill sheep. This team found a way to turn the hunting (sugar eating) bacterium into herding (CO2 eating) bacterium.
Milo and his team hope to make their bacteria grow faster and live on lower levels of CO2. They are also trying to understand how the E. coli evolved to eat CO2: changes in just 11 genes seemed to allow the switch, and they are now working on determining how.
See a short video explanation of the work here:
From a project management perspective here are a couple of takeaways:
Persistence – this team had to deal with setbacks when the bacterium did not respond as they had hoped to the first modifications
The multi-disciplinary and global nature of projects – this team combined engineering, biology, genetics, analytics – and many others to achieve success.
Long-term view – this team focused their efforts on producing a solution aimed at helping to solve climate change.
Reference: Nature 576, 19-20 (2019)
Also, you can find the technical article from Cell right here: https://www.cell.com/cell/pdfExtended/S0092-8674(16)30668-7