Ariel Furst

Many of the Furst Lab’s research projects involve the augmentation of microbial activity with abiotic materials. “Microbes can pretty much do everything we have tried to do chemically,” says PI Ariel Furst, the Paul M. Cook Career Development Assistant Professor of Chemical Engineering. “They are like tiny chemical factories.”

Below, we explore a Furst Lab project to develop microbes as affordable, regenerative alternatives to chemical fertilizers. The lab has developed a technique to fit nitrogen-fixing bacteria with nanoscale “suits of armor” to protect the microbes against the rigors of processing, transport, and distribution. We also look at Furst’s emerging research into using augmented bacteria to recycle textiles, breaking polyesters down into their building blocks.

Finally, we examine a project with a very different abiotic-biotic interface. Furst has developed a more efficient electrocatalytic route to convert CO2 to syngas that integrates strands of DNA to connect electrodes to catalysts.

We develop technologies that are accessible and can help achieve energy justice.

The Furst Lab translates their learnings into affordable technologies, reinforcing the lab’s mission to develop equitable solutions. “There are many marginalized and disadvantaged communities that have been disproportionately impacted by industrialization,” says Furst. “We develop technologies that are accessible and can help achieve energy justice.”

A Sustainable Alternative to Chemical Fertilizers
The production of nitrogen-based chemical fertilizers generates about 1.5% of global greenhouse gas emissions. Chemical fertilizers also degrade soil, pollute water and air, create harmful algae blooms, and damage native ecosystems.

For several decades, ecologically minded farmers have experimented with sustainable alternatives to agrochemicals, including the use of nitrogen-fixing microbes for fertilization. “In native systems, nitrogen-fixing microbes such as bacteria and fungi supply nutrients to plants and protect them from pests,” says Furst. “But chemical fertilizers and pesticides are destroying the native microbes. By delivering live microbes back to the soil, we can keep the soil healthy long past their application.”

One reason the microbial agricultural business is only a $4 billion industry compared to $250 billion for agrochemicals is that it is difficult to store and transport microbes. Typically, farmers must grow microbes on-site in expensive fermenters. To achieve agrochemical efficiency, they need to apply other regenerative techniques such as reduced tilling.

Furst has developed a more affordable and sustainable green fertilizer alternative based on her prior research to enable biotherapeutic microbes to survive the caustic environment of the human gut. Realizing that attempts to chemically stabilize these microbes had largely failed, Furst took a different approach: engineering hardened bacteria for biotherapy using organic-inorganic hybrid materials.

“Many microbes struggle to live without familiar neighbors and nutrients,” says Furst. “It is hard to formulate them so they can be delivered to challenging environments such as the stomach or chemically treated soil. Our approach is to create little suits of armor for the microbes that protect them from environmental stressors.”

The armor is comprised of a metal-phenol network (MPN), which combines organic polyphenols and metals. The polyphenols are derived from food grade components such as green tea extract or coffee tannins. These organics are combined with metals found in vitamins such as iron and manganese.

After Furst demonstrated that her hardened biotherapeutic bacteria survived much better than chemically treated microbes, she investigated whether the technique could work with soil microbes. “It turns out that many of the microbes in both environments share an aversion to high levels of oxygen, which our coatings protect against,” says Furst. “It makes sense when you think about it: You are what you eat.”

The similarity of the microbes made it easier to transfer the process for microbial fertilizer applications. “In either case, the metals and polyphenols are mixed in a solution of microbes,” says Furst. “They combine and naturally wrap around the microbes like the self-assembling Iron Man suit.”

The armor enables the bacteria to survive drying so they can be affordably transported to farmers. The coating also protects from stressors during the journey, including high heat, humidity, and UV and oxygen exposure.

The coated microbes show vast improvements in seed germination rates compared to uncoated microbes from fermenters. Only a thin coating is required -- about five grams for microbes distributed over a hectare of land – and there is no need for on-site fermenters.

Our microbes can manufacture antifungal compounds for use as pesticides. The microbes sense their environment and turn on the manufacturing process when needed.

The armored bacteria can do far more than nitrogen fixing. “We are creating customized mixtures of microbes that do everything agrochemicals can,” says Furst. “Our microbes can manufacture antifungal compounds for use as pesticides. The microbes sense their environment and turn on the manufacturing process when needed.”

In 2022, Furst co-founded the startup Seia Bio to produce the custom-coated microbes. “Many agrochemical companies have invested heavily in regenerative agriculture R&D, but they struggle to scale for manufacturing,” says Furst. “The microbe engineering process often makes the microbes more delicate and therefore harder to produce at scale. Our goal is to help customers improve the manufacturing process while also enabling native microbes to prosper.”

The Furst Lab is now investigating a third application for its protected microbes: manufacturing green construction materials. “We are looking for ways to use hardened microbes to reduce the carbon footprint of cement and create strong hybrid materials,” says Furst.

Making Textile Recycling More Affordable
In another project using a different type of engineered microbe, the Furst Lab is recycling textiles that would otherwise be shipped to landfills. Typically, the used clothes are shipped to landfills in developing countries, increasing the emissions footprint and polluting the environment.

“We are going through clothes much faster than we used to,” says Furst. “In the US we each throw away about 80 pounds of clothes per year, which can degrade into harmful microplastics.”

Current textile recycling technologies are expensive and require dangerous chemicals that must be used in a lab, says Furst. “Chemical recycling also destabilizes the polymer, which reduces its effectiveness each time it is recycled.”

Furst’s approach is to take enzymes that naturally degrade compounds in our bodies and embed them on the surface of microbes. The process stabilizes the enzymes and makes them easier to deploy.

“By applying our material to textile waste, we can degrade polyesters within about a week,” says Furst. “On textiles with long polymer chains, we can achieve 100% degradation, and no microplastics are released. The polyester is converted to small molecules called monomers which can be used to make more polyester.”

Affordability was a primary goal. “At about $10 per kilogram, our materials are inexpensive, and we can degrade between 100 to 1000 kilograms of waste with a single batch of microbes,” says Furst. “This could contribute to a circular polyester economy, reducing the manufacture of new monomers, which are usually produced from fossil fuels.”

If the technology scales as expected, it might even become profitable to recycle and recover materials from a \variety of other plastics, says Furst. “Most landfilled plastics are comprised of different polymers. We are now engineering microbes to degrade each type, and we can mix them together to create a customized solution.”

DNA: an Organic Booster Shot for Electrocatalysis
Carbon dioxide capture and conversion continues to struggle for one main reason: high cost. Absent taxes or regulations, there are few incentives to sequester carbon. Carbon conversion using electrocatalysis may provide a more profitable alternative.

“If you shove enough electrons into carbon dioxide you can create valuable chemicals to offset the cost of capture,” says Furst. “But it is still much cheaper to make these feedstocks through fossil fuels.”

There are two main types of electrocatalysts, which combine an electrode with a catalyst to enable CO2 conversion. The typical approach is to place the catalyst in solution so it can interact with an electrode. Yet it takes a long time for the catalysts and CO2 to diffuse to the electrode. Another approach is to create solid electrodes that integrate the catalysts. Solid electrodes catalyze reactions faster but requires expensive precious metals. Both designs suffer from high failure rates due to contaminants in CO2 streams.

The Furst Lab has developed a novel approach to CO2 conversion that decreases the energy requirements and improves catalytic efficiency. The technology converts CO2 to carbon monoxide, which can be used to create synthesis gas (syngas), a starting material for many chemical and manufacturing processes.

“We can make syngas for about $350 a ton as opposed to $600 a ton for standard CO2 conversion,” says Furst. “Capturing and converting CO2 can finally become profitable.”

Furst’s process is based on solution-phase electrolysis but adds a surprising twist: DNA. Furst came up with the idea based on her PhD research: adding DNA to electrodes for medical diagnostics.

“DNA had never been successfully applied as a material beyond diagnostics,” she says. “But I saw a potential application in carbon conversion.”

DNA acts as a highly conductive wire, increasing the current throughput. As a three-dimensional scaffold, it behaves much like a zipper. “By attaching half of the DNA zipper to an electrode and the other half to the catalyst, we can zip complementary strands together via hydrogen bonds,” says Furst. “The catalyst is directly attached to the electrode, limiting its movement while maintaining access to CO2 in solution. As a result, we use about 30% less energy than a typical process.”

DNA can also unzip, thereby enabling the regeneration of electrodes. “We unzip the DNA by adding hot water and flow in fresh, single-stranded DNA modified with a catalyst,” says Furst. “The DNA finds its partner on the electrode and hybridizes to it through base pairing. This lowers system cost because you don't need to replace everything when your catalyst inevitably gets poisoned.”

DNA-connected electrocatalysis offers additional advantages. “We can use carbon electrodes, which are far cheaper and greener than precious metals, and we can control the DNA length and sequence to control melting temperature,” says Furst. “The DNA also stabilizes the catalysts, enabling durability for over a week compared to one or two hours for a typical catalyst. As a result, you do not have to swap out the catalyst every few hours.”

Furst’s “DNA immobility” technology requires significantly less catalyst material than conventional systems. This is likely due to a reaction rate that is more than 100 times faster than standard processes. “When you combine the reduced catalyst requirements with improved speed and efficiency, the overall conversion is about half the standard cost,” says Furst.

Like most CO2 conversion technologies, Furst’s technique can also generate hydrogen. “We can tune how much hydrogen we create, and we don't have to isolate our products for syngas,” says Furst. “We can generate a custom mix.”

Furst recently co-founded a company to commercialize the technology called Helix Carbon, which won the 2024 MIT Climate & Energy Prize. The company has developed a process that can generate more than a ton of syngas per day.

Target customers are manufacturers that can use syngas in their operations. “Our goal is to integrate our process into a system that can be plugged into existing CO2 capture processes,” says Furst. “Our customers can use the syngas for their chemical processes or sell it. Alternatively, we can collect a company’s CO2, convert it to syngas, and sell it back to them.”

Furst has begun looking beyond CO2 to syngas conversions including ethylene, ammonia, and urea. “The DNA enables us to easily swap out catalysts depending on the job,” she says.