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LanzaTech: Engineering The Future

A recent visit to New Zealand-American synthetic biology company, LanzaTech, opened my eyes to what the term “paradigm shift” means. LanzaTech is an industrial chemicals company that leverages innovations in biology, artificial intelligence, and precision engineering to create the molecules that make everything from yoga pants to jet fuel possible – all without digging up fossil fuels.

This is the third article in a series that delves into the amazing engineering innovations pioneered by LanzaTech. As background reading, here is my Forbes overview of LanzaTech, and here is a deep dive into the science of “synthetic biology” that underpins the company’s success.

LanzaTech has invented a commercial-scale bioreactor that feeds greenhouse gases to a species of anaerobic bacteria; these bacteria metabolize the gas to produce sustainable, carbon sequestering ethanol (CH3-CH2-OH). Ethanol is a substance that is valuable in its own right and can also be blended into gasoline or refined to create a variety of products.

The company has also discovered a way to genetically modify the bacteria, coaxing them to metabolize other commercially important target molecules like acetone (CH3-CO-CH3) and IPA (C3H7-OH) in a completely sustainable and carbon sequestering way.

Building the bioreactor was an enormous engineering challenge. Building the infrastructure to create and test new genetic strains was yet another.

LanzaTech’s Bioreactor

The challenge to LanzaTech engineers was to create a system that could simply bolt on to an existing industrial facility (such as a steel mill or a municipal landfill) to produce industrial chemical building block molecules using the host facility’s “off-gases.”

One of the biggest issues behind executing on this vision is a timing mismatch. Owners of a steel mill, for instance, want to maintain capacity utilization at near 100% to offset the cost of equipment depreciation. If managers operating steel mills had their druthers, they would run them 24x7x365.

Contrast this preference with the natural environment of a colony of the anaerobic bacteria LanzaTech is using to create ethanol. If you recall from my last article about LanzaTech’s science, the natural environment for these bacteria is the guts of a rabbit, so the process by which the bacteria naturally propagate is in one-bunny batches.

Trying to synch up the continual processes favored by industrial manufacturing facilities and the batch processing favored in a natural or laboratory setting is challenging. Essentially, what LanzaTech engineers had to do was to figure out how to create a very large, very efficient rabbit gut environment for the bacteria that could handle the demands of processing continually incoming food sources.

The process of making a giant, industrial rabbit gut environment in which bacteria would thrive was no easy task – LanzaTech has been granted over 1,000 patents and has nearly half again as many patents pending.

The bacteria are inserted into a tower in an aqueous solution. The off-gasses from the facility are treated (for instance the gas coming out of a steel mill is cooled) and some toxic impurities are filtered out. The off-gases are then pressurized and injected into the bacteria-containing tower in the form of easy-to-consume micro-bubbles.

The bacteria digest the gases, clone themselves to create more bacteria that will consume more gas, and excrete ethanol, which is removed for use as-is, or routed to another processing unit where it can begin creating another target hydrocarbon through a separate chemical process.

After enjoying the best life an anaerobic bacteria can enjoy – eating, reproducing, and excreting to their hearts’ content – the bacteria die, and their bodies are removed from the tower. Those dead bacteria are also an economic biproduct rather than “waste” (in the Industrial Revolution paradigm sense of the word) as they can be used as agricultural fertilizer or processed into animal feed.

The LanzaTech design has a few big advantages.

First, the process can handle very different input streams equally well. LanzaTech has already bolted several bioreactor complexes onto steel mills, but the same bioreactors can also be bolted on to gasification units that convert organic waste — anything from municipal landfill trash to agricultural clippings — into gas nutrients for ethanol-producing bacteria.

Part of the reason for this feedstock flexibility is the fact that the bacteria can process gases even when they contain a certain level of impurities (which waste off-gases usually do). The rate at which the bacteria die off may increase some, but because the process grows new bacteria continually, this does not cause a breakdown in the system. This ability to handle non-standard feedstock represents a big advantage over legacy catalytic methods, which are very sensitive to impurities – an advantage I discuss more below.

Second, because the process is carried out by living organisms in a low heat and low-pressure environment, the metals used in the construction of the refinery need not be expensive, specialty steel. The equipment is cheaper, and you don’t need to worry about your processing tower blowing up because someone wasn’t watching a critical pressure gauge somewhere.

Third, because the reactor works the same for any strain of anaerobic bacteria inserted into it, the same facility can be converted easily from one producing ethanol to one producing another of the chemicals that LanzaTech’s new genetic strains of bacteria have been bred to produce. The same facility might choose to produce one chemical one quarter because the price of that chemical is high, then produce a completely different one the next quarter as market prices for commodity chemicals fluctuate in the market.

Last, because the process is a biological one, it is extremely efficient from the standpoint of completely using up the incoming off-gases. The off-gases are to bacteria what Oreos are to a corporate break room. Just as you would not expect to have any Oreos laying around at the end of the day in a break room, the off-gases are nearly completely consumed by bacteria. Any waste-product “crumbs” the bacteria miss end up getting recycled and used in later processing steps.

The one weakness of the biological process on which the bioreactor is based is that, according to LanzaTech founder and Chief Scientific Officer, Dr. Sean Simpson, trying to engineer bacteria that can remove oxygen atoms from a molecule is very hard. This means that, for instance, it will be difficult to engineer a bioreactor that creates transportation fuels directly because the transportation fuels are pure hydrocarbons – chemicals that contain only hydrogen and carbon atoms without oxygen atoms mixed in.

That said, looking back at the first strong point above, the LanzaTech process can accept an enormous array of different feedstocks. Simpson believes that the great value in LanzaTech is that it can take in a variety of gases that otherwise would be discarded into the atmosphere as waste to produce a standardized feedstock such as ethanol. This standardized, energy-rich feedstock can subsequently be converted into a hydrocarbon through more-or-less conventional chemical processes.

Keep in mind that the crude oil Exxon or BP pulls out of the ground cannot be used in that form. The crude must be shipped to a refinery and distilled into the various handy products to which we have become so accustomed. Crude oil is, in other words, an intermediary product that only has value as a standardized, energy-rich feedstock for other products.

In contrast to the black gold drilled by oil majors, LanzaTech produces ethanol. Ethanol has value in its own right and is also a standardized, energy-rich feedstock for other products. The big paradigm shift our civilization needs is to switch feedstocks from fossil carbon to sustainable, replenishable ones such as ethanol.

LanzaTech’s SynBio Engineering

In addition to the creation of the ethanol bioreactor, LanzaTech had to create the engineering infrastructure to carry out the scientific advances mentioned in the previous article in this series. The idea is to create new strains of the anaerobic bacteria that will metabolize greenhouse gases (GHGs) in a slightly different way, allowing for a chemical other than ethanol to be created.

The first step of the process is genetic sequencing and design, carried out by the same sorts of scientific tools one would find in a university lab.

Once the new sequences are designed and created, they are inserted into bacteria in a device known as a biofoundry. This biofoundry produces small batches of genetically modified bacteria. Because of the large number of modifications that must be tested in each step, the foundry is powered by robotic assistants – an assembly line that places new genetic “fixtures” in each microscopic chassis. The LanzaTech biofoundry is the first anaerobic biofoundry in the world.

Once a genetically-modified colony has been started in the biofoundry, the process moves to an R&D lab where different proportions of industrial gases are fed into benchscale fermentation bioreactors – a one-bunny batch’s worth of an aqueous solution and the newly created genetic strains.  

Throughout this process, it is not only the new genetic strains that are being tested, but also the temperatures and pressures at which gases are inserted into the bioreactors, as well as the size of the bubbles of gas created by the injection process.

The lessons learned at the benchscale bioreactors are incorporated into the design of a large prototype bioreactor. This prototype forms a working model for the industrial-scale versions of the bioreactors, like the one operating in China.

Putting it All Together

The result of all this work are commercial-scale chemical factories powered by the off-gases of other industrial facilities. The SGLT plant in China – a relatively modest installation – sponges up over 130,000 metric tons of CO2 equivalents associated with a steel mill every year. Those sequestered GHGs equate to the annual tailpipe emissions of over 28,000 cars!

The facility planned for Ghent, Belgium – attached to an ArcelorMittal steel mill – will soak up over 350,000 metric tons of CO2 equivalents per year – an impact roughly the same as removing 76,000 cars from the road. With only two facilities, then, LanzaTech is removing the equivalent of the over 100,000 cars’ worth of emissions.

This carbon is permanently sequestered by chemical transformation into other products. The Ghent facility alone will produce 62,000 metric tons of ethanol per year, which is worth something like $74 million per year at today’s spot price.

The ethanol created at LanzaTech facilities is being used as a feedstock to create the plastic (PET) bottles used to hold everything from drinking water to shampoo, and can be extruded into PET fibers, used in synthetic fabrics in general and Lululemon yoga pants in particular. The acetone that another of LanzaTech’s strains can produce is used in everything from cosmetics to the electronics manufacturing process and everyone knows what isopropyl alcohol, the product of another of LanzaTech’s strains, gets used for in these days of Covid-19.

I would invite the gentle reader to consider the implication of the paragraph above. Think for a moment of all the products mentioned there that you have used today or that are within reach of you at this very moment. Using LanzaTech processes, these ubiquitous items – markers of our material prosperity and high living standards which legacy producers can only manufacture while emitting GHGs – will become permanent carbon sinks.

That is what a paradigm shift looks like.

Intelligent investors take note.

https://www.forbes.com/sites/erikkobayashisolomon/2021/09/30/lanzatech-engineering-the-future/