ETH Zurich Finds Green Feedstock Alternative to Fossil to Make Chemicals

The chemical industry is among the world’s heaviest consumers of fossil fuels and, with that, emits tremendous volumes of CO2—totaling around 925M metric tons in 2021 alone (the latest available figures), according to McKinsey & Company. Researchers at ETH Zurich in Switzerland are working on a novel way to help lessen the industry’s carbon footprint: they’ve found a non-fossil source of carbon to make plastics and, possibly, other near-countless products that chemical plants mass produce.

Instead of crude oil, the ETH Zurich team leverages methanol as feedstock, with the help of E. coli. The E.  coli feeds off the methanol to reproduce, and it ultimately converts carbon from methanol into sustainable products.

While this may sound like weird science—most people think of E. coli as a nasty bug lurking in the gut—the bacterium has long been used in bioproduction. But this is the first time it’s been put to the test to see if it can utilize methanol to make products.

“Because E. coli has been used for so long, we know how it behaves and works and over time we have gotten good at changing its behavior, so it does what we want it to do,” says Michael Reiter, a researcher at the Institute for Microbiology, ETH Zurich, and study co-first author.

He and his research partners have produced four compounds, each with large markets for polymer production: lactic acid, polyhydroxybutyrate, itaconic acid, and p-aminobenzoic acid.

Both lactic acid and itaconic acid are monomers that can be polymerized to potentially create multiple applications— beverage cups, plastic cutlery, paints, and synthetic fibers, to name a few.  

Polyhydroxybutyrate is a small chain of monomers utilized to further build out polymers of a desired length; these pre-existing structures require less energy to drive chemical processes than when starting from a single monomer.

The fourth compound, p-aminobenzoic acid, contains a ring of carbons, which gives it unique functional properties that make it suitable as an intermediate for pharmaceutical applications, to make dyes or skin care products, among uses.

Showing these four products can be produced effectively is a start on the way to commercializing the technology.  But for today, the work out of Zurich is just at a proof of principle stage.

“So, what we want to show now is that we have a platform that can be leveraged to make all sorts of chemical products. Depending on how we program our [E. coli] cells we can create a wide range of products without needing to come up with different technologies,” Reiter says.

He describes every cell as a little machine facilitating conversion of methanol.

“We need a lot of these ‘tiny machines’ to take a handful of cells and make billions more of them to convert sufficient amounts of methanol into climate-neutral products. And that’s what our [synthetic] E. coli does.”

In nature there are plenty of organisms that can feed off of methanol, but they are less understood, and so far, there are no industrial processes using them.

“So rather than develop the processes around unfamiliar organisms we use what we are familiar with, but just teach it another trick, which is the utilization of methanol,” he says.

But training E. Coli to perform this feat was not easy.  Moving from concept inception to proving it could be done has taken nearly 10 years of due diligence in the lab.

“Enabling E. coli to grow on methanol requires a complete rewiring of the cell's metabolism. I was really surprised to see how well our engineered E. coli was able to convert methanol into desired products. This is more than I had hoped for and gives me great confidence for future applications,” says professor Julia Vorholt, ETH Zurich Institute of Microbiology and corresponding study author.

“We are now trying to better understand exactly how E. coli changed to allow it to use methanol, with the idea that this will help further improve efficiency of the overall downstream process,” says Timothy Bradley, a PhD student at the Institute for Microbiology at ETH Zurich and co-first author.

Reaching for meaningful scale will require gaining more insight into genetic changes that lead to bacteria using methanol in the way it does. And it will require optimizing the organism’s metabolism so it can more efficiently and quickly use methanol.

The research team was recently awarded a grant from the Swiss government to develop specific applications and pursue commercialization of the technology. The plan is to spin out a company within the next year to make the first set of products, then to fully scale over five to 10 years. As they advance along their trajectory, they are in talks with chemical industry players as potential offtakers.

For manufacturers, independence from fossil not only has climate implications but could have geopolitical and economic implications as new and more diverse feedstocks become available domestically. Green methanol is an abundant and potentially strong candidate; it can be sourced from municipal solid waste, agricultural waste, or even sequestered carbon.  So, the possibility for both a healthy supply and demand is real.

The ETH Zurich team is hopeful that in time they will be able to tap into this emerging alternative to fossil not only to produce chemicals that are less carbon intensive, but maybe even with a zero-carbon footprint.