Using Enzymes To Capture Carbon In The Fight Against Climate Change

It’s clear that we can no longer avoid the impacts of climate change — we’re already experiencing the economic, societal, and ecosystem impacts of extreme weather events, rising temperatures, and melting ice caps. Although scientists and governments have been warning us for decades about the dangers of the unbridled release of industrial carbon into the atmosphere, the global average atmospheric carbon dioxide hit a new record high of 414.72 ppm in 2021.

It is now evident that we’ve moved from trying to stop climate change to trying to minimize its impacts. To do this, we must reach carbon negative status by the latter half of this century. Achieving this goal will be impossible without efficient carbon capture and storage (CCS). Currently, CCS captures 40 million tons of carbon annually.

This might sound like a big number, but it’s only a mere 4% of the 1000 billion tons that must be captured to meet climate targets by 2030 as laid out in the Paris Agreement. That’s a huge deficit to make up in only 7 years. A purposeful, ambitious combination of innovation, policy, and financial backing is the only way to make sure we don’t drop the ball again when it comes to protecting our planet.

Building on one of nature’s oldest processes

CCS has actually been around since the 1970s, but for most industrial players, it isn’t exactly a great business model. Current technologies are so expensive that they must achieve 90% efficiency in order to pay for themselves. And to achieve carbon neutrality, companies must go beyond this baseline and achieve 100% efficiency. There is currently little impetus for companies to invest the time and financial resources to attain 100% efficient CCS, however, because doing so doesn’t exactly result in a marketable product.

Fortunately, there are a few ways to address this challenge. One of the most obvious is to make the process itself more efficient (and therefore, less expensive). As we’ve already seen so many times before, often the best way to make a process more efficient is to look to nature.

“Sometimes we have the idea that something has just been invented — but that is not the case with carbon capture,” says Klaus Lassen, Head of Carbon Capture & Storage at Novozymes. “It is not a new thing for nature: one of the most explicit examples is our own breathing.”

Lassen will be participating in a lighting talk at the SynBioBeta Conference in Oakland at the end of this month, where he’ll describe the work that Novozymes is doing to make CCS a more efficient, affordable option. That work is centered around an enzyme that has existed in nature for as long as breathing has been a thing: carbonic anhydrase.

Carbonic anhydrase is a two-way enzyme that captures CO2 from our cells and converts it into carbonate so it can be safely transported through our bloodstream to our lungs, where carbonic anhydrase then turns it back into exhalable CO2. It’s an elegant process that Novozymes, together with global biotech Saipem, is applying on an industrial scale. Called enzymatic carbon capture, the process was developed as a more efficient, less expensive, and greener alternative to the solvent-based capture technology that has been in use since the 1970s.

Green carbon capture is possible

Solvent-based carbon capture, also called amine carbon capture, uses solvents created from nitrogen to capture CO2 from flue gasses. Captured CO2 can then be converted back into gaseous form and released when the solvent is heated to 120oC. The released CO2 can then be directed elsewhere; often, it is pushed underground for enhanced oil recovery. While this process has been optimized over the last 50 years and is highly efficient, there are some critical issues that have complicated scaled application.

Before you can even capture CO2, flue gasses must be purified. Then, once you’ve captured the CO2, the costs of heating the solvent to release captured CO2 back to where you want it represent up to 25% of the cost of the entire CCS pipeline. Additionally, nitrogen is already a significant environmental concern — with each ton of carbon requiring half a kilogram of nitrogen to produce solvent, the amount of nitrogen released into the environment during scaled carbon capture is just going to do more damage to our planet’s ecosystems (along with other toxic byproducts released during the process). Perhaps most nonsensical, however, is the carbon released into the environment during traditional CCS, first to provide the energy to heat the solvent and later during recovery of the oil captured CO2 is pushed back into the ground to help extract.

Enzymatic carbon capture, on the other hand, is both an incredibly efficient and completely benign process. Carbonic anhydrase can absorb a million CO2 molecules per second. It’ll work on flue gasses as they exit the flue — no purification required. Because the waste product of the enzyme is bicarbonate, equipment doesn’t become corroded and lasts much longer, saving on materials costs, and the environment isn’t contaminated by toxic byproducts. And the enzyme is activated at only 80oC, meaning that waste heat that is produced during whatever industrial process the company is engaging in can be redirected to facilitate the release of captured CO2.

But enzymatic carbon capture is a very new technology compared to traditional carbon capture methods. It’s not optimized and currently suffers from scalability challenges just like traditional methods. And it’s not the first choice for companies that view CCS as nothing more than a nuisance and are more likely to choose the more established technology.

That’s precisely what Novozymes and Saipem are working to change. Saipem’s CCS process, leveraging Novozymes’ optimized carbonic anhydrase enzymes (derived from high temperature stable microorganisms), currently captures 200 tons of CO2 per day. The companies are working to increase the efficiency of both the carbonic anhydrase enzyme and the enzymatic carbon capture process as a whole, providing companies with an economically viable option to capture carbon without inflicting additional environmental damage. But to fully realize the potential of enzymatic carbon capture, considerably more buy-in is required. And the key to that buy-in, according to Lassen, lies largely in the hands of policy makers.

Stop talking about policy and start enacting it

To stop CCS — whether amine or enzymatic — from being nothing more than a nuisance, we need regulatory policies that make not investing in CCS infrastructure the more expensive option. Some programs already exist: the European Union, for example, has implemented the EU Emissions Trading Scheme, which caps annual CO2 emissions and sells emissions certificates to companies, who can then reduce their emissions and sell surplus certificates at a profit or, if they fail to invest in emissions-reducing strategies, can purchase additional certificates to increase their ceiling.

Trading carbon credits like this could actually become a thriving, viable market making significant contributions to reducing greenhouse gas emissions. On the other hand, tax credits such as Canada’s CA$2.6 billion credit for CCS programs and the U.S.’s Infrastructure and Jobs Act, which will inject USD $12.6 billion for CCS and related programs, provide financial relief and motivation for companies to invest in developing and implementing CCS strategies.

Financial incentives will certainly go a long way when it comes to motivating companies to implement CCS and other emissions-reducing strategies, but they don’t go too far when efforts are hamstrung at ground level — literally. To truly reach carbon neutral and in time carbon negative status, says Lassen, all the carbon in the oil and gas that we have burned the last century needs to be put back underground, where it must stay for safe storage. And that, unfortunately, is harder than it sounds. Policy around regulatory requirements and beneficial financing schemes is still missing, as is the infrastructure to handle vast amounts of captured CO2.

“In the U.S., if you’re a landowner you own the Earth down to the core, which makes it possible to store CO2 on site if you have the right geology that can contain CO2. But that’s not the case in Europe, where you need a permit to store CO2 even on your own land” explains Lassen. “So you need to transport captured CO2 by truck, train, or pipe to the nearest authorized storage site. In northern Europe these storages are mainly constructed in the North Sea and then you will need additional ship transport out onto the sea where you can then inject it into the earth. It becomes extremely expensive and just leads to more transportation-related emissions.”

Competition between countries to develop CCS-enabling technology can, and hopefully will, drive much-needed legislation across the globe, says Lassen.

“The US, EU, and China are competing to be the technology providers of the future and to protect their own regions. Imagine if you’re in the U.S. and you engage European engineering companies to build the capacity — that would represent a huge milestone on the payment balance between the two countries. So, as soon as the Biden Administration introduced the Inflation Reduction Act [which includes enhancements to the 45Q tax credit and accelerates CCS deployment], it really put a fire under EU legislation, and I think these both will also put a burner under what is happening in China.”

According to Global CCS Institute’s Global Status of CSS 2022 report, things are indeed headed in the right direction, with several policy and funding initiatives enacted by the U.S., European, and Asian markets to accelerate CCS technology development and use.

Put your money where your mouth is

Tax breaks and other governmental investments are a great start — but they’re just a start. Considerable financial resources will be needed to accelerate, optimize, and roll out CCS globally. Several big tech companies, including Microsoft
MSFT
and Amazon
AMZN
, are leading the charge.

Pledging to eliminate its carbon footprint by 2030, Microsoft plans to inject USD $1 billion into the development of CCS technologies and plans to make carbon reduction an explicit aspect of their supply chain procurement processes. Similarly, Amazon plans to go carbon negative by 2040 by investing in renewable energy sources.

But to really have an impact, the biggest contributors to carbon emissions — industry, transportation, energy producers, and even agricultural giants — need to get on board, too. Momentum is building, with coalitions like CCS Europe launching with buy-in from and participation by players in the shipping, concrete, and other industries. Additionally, organizations like South Pole work with industry players around the world to develop and finance projects that help reduce carbon emissions.

Thinking above the ground

Much of the innovation around carbon capture won’t just stop at storing carbon underground but instead will aim to repurpose captured CO2. There is actually a huge push among the shipping industry to invest in alternative fuel methods, such as green methanol (which can be made from captured CO2) due to increased legislative pressure.

A wide range of other industries are also pushing for the production of alternative fuels that either use captured CO2 or reduce carbon emissions in their production. Partnerships like that between Fidelis New Energy and Grön Fuels, LLC, for example, are leading the charge in the production of sustainable aviation fuel, renewable diesel, and green hydrogen. And of course, synthetic biology efforts will surely continue to develop ways to engineer bacteria and other organisms to take CO2 and convert it into medicines, food ingredients, and more.

There’s no doubt that we are in one of the most precarious positions we’ve ever been in as the human race, but we also are more armed than ever to actually get ourselves out of the mess we’ve created. All we need to do is work together and start turning our words into actions.

“Mitigating the climate crisis is a huge challenge for global society. Novozymes and Saipem are ready to walk the talk with new technology to bring down costs and to provide the market with a better option,” Lassen told me. But he also reminded me of one very important thing: this is not a one-way street; we all need to do our part. “We are members of a combined global society that needs to come together to not just think about but to actually develop carbon capture capabilities and save our planet.”

Thank you to Embriette Hyde for additional research and reporting on this article. I’m the founder of SynBioBeta and some of the companies I write about, including Novozymes, are sponsors of the SynBioBeta conference. For more content, you can subscribe to my weekly newsletter and follow me on Twitter and LinkedIn.