Welcome to this week's issue of Deep Tech Brief.

Every Saturday, we break down deep tech companies building genuinely hard things, in plain language. No jargon, no hype.

Three companies this week: on-farm fertiliser in Denmark, cheap jet fuel ingredients in London, and glue made from a wood byproduct in Finland.

Let’s dive in.

In 1913, Fritz Haber and Carl Bosch worked out how to pull nitrogen out of the air and force it together with hydrogen to make ammonia. It is arguably the most consequential chemical process ever industrialised. Roughly half the nitrogen in your body got there through it.

It is also brutal. The reaction runs at 400 to 500 degrees, at pressures over a hundred times atmospheric, and the hydrogen usually comes from natural gas. Ammonia production accounts for something like 1.3% of global carbon dioxide emissions on its own. Because those conditions are only economic at enormous scale, plants are vast and centralised, and the product then travels by ship, rail and truck to the field.

That structure has two consequences. Farmers are exposed to a long supply chain and to the gas price, as European growers found when gas spiked and fertiliser costs followed. And where no billion-dollar plant will ever be built, fertiliser is simply scarce: Africa accounts for around 4% of global use.

NitroVolt, a spin-out from the Technical University of Denmark, wants to make the plant small enough to sit in the farmyard. Its Nitrolyzer is a container-sized unit that takes in air, water and electricity and produces ammonia on demand, using an electrochemical process rather than heat and pressure. No fossil input, and no supply chain.

This is a hard target. Haber-Bosch is the most studied reaction in industrial chemistry, and the iron catalyst still used in plants today was found more than a century ago. People have been trying to beat it ever since.

Where they are: founded in 2023 by Suzanne Zamany Andersen and Mattia Saccoccio, on research begun at DTU's physics department in 2017, with roughly $4.6 million raised. A €3.5 million seed in late 2024 brought in BackingMinds, Denmark's EIFO, the EQT Foundation and Breakthrough Energy, the Gates-backed fund that had already given the team a fellowship. The lab is three shipping containers bolted together in a factory hall outside Copenhagen, and the company is targeting a production facility in 2027.

Worth watching, because making the unit small changes who can buy fertiliser, not just how clean it is. The milestone ahead is scale in the unglamorous sense: showing the electrochemical route keeps its efficiency as the units get bigger, on the way to that 2027 facility.

Learn more: nitrovolt.com

Aviation has agreed it needs synthetic fuel. It has not worked out how to afford it.

Making e-fuels needs two ingredients: hydrogen and carbon dioxide. Most hydrogen today comes from steam methane reforming, a 1920s process that cracks fossil gas with steam. The clean versions of both inputs are expensive, and the expense is almost entirely electricity. By Ki 13's figures, splitting water to get hydrogen takes around 50 kilowatt hours per kilogram, and pulling carbon dioxide out of the air takes somewhere between 2,000 and 3,000 kilowatt hours per tonne. That is the whole reason a litre of e-kerosene costs several times what refined jet fuel does.

Ki 13, based in London, changes the feedstock. Instead of water and air, it starts with woody residues, the sawdust and agricultural leftovers forestry and farming generate anyway. Those go into a mildly heated solution containing a catalyst, which breaks the biomass down into biogenic carbon dioxide and hydrogen ions. The spent catalyst is then regenerated in an electrolyser and looped back round to break down more biomass.

The clever part is what that regeneration replaces. In ordinary water electrolysis, roughly half the electricity goes into producing oxygen you do not want. Ki 13's catalyst loop takes that step out, and the company reports around 25 kilowatt hours per kilogram of hydrogen and 300 per tonne of carbon dioxide. Half the electricity for the hydrogen, and an order of magnitude less for the carbon, from one process that produces both at once.

Where they are: founded in 2022 as Ki Hydrogen out of the Carbon13 venture builder. Chief executive Koji Muto previously worked on the UK's largest hydrogen project at ExxonMobil and was an early hire at both a small modular reactor company and a direct air capture company. A $5 million seed announced on 2 September was led by HICO Investment Group, which also backed the pre-seed, with Innovate UK adding non-dilutive match funding. All of it goes into an industrial pilot plant.

Worth watching, because the company is attacking price rather than emissions, and price is what has actually stalled synthetic fuel. The milestone ahead is the pilot: proving those energy numbers hold outside the lab, and that enough biomass residue can be gathered cheaply enough to feed a real plant.

Learn more: ki-13.com

There is a saying in the forest industry that you can make anything out of lignin except money.

Lignin is the natural adhesive holding wood fibres together, and makes up roughly a quarter of a tree. Pulp mills strip it out to get at the cellulose, producing about 50 million tonnes a year as a byproduct. More than 95% of it is burned for heat. The kraft pulping process that creates it dates to 1884, and burning the lignin is essentially what mills have done with it ever since.

The reason is not lack of interest. Lignin is chemically messy: its structure varies by tree, by mill and by batch, and industrial buyers need inputs that behave the same way every time.

LignoSphere, out of Aalto University, reshapes it. Its patented process turns raw lignin into uniform spheres, tiny consistent particles that behave predictably where the bulk material does not. Founder Kalle Lintinen, a researcher at Aalto and later at Häme University of Applied Sciences, found an efficient way to form them using ethanol and a solvent that the process then recycles in a closed loop.

What comes out is adhesive and coating material that sticks to metal, concrete and wood, with promising wear and corrosion resistance, tested at high shear strengths and aimed at engineered wood like glulam. The commercially important detail is that it behaves like a conventional epoxy on the production line, so a factory does not have to change anything to use it.

Where they are: pre-seed funding closed in May, led by Kiilto Ventures, the venture arm of a Finnish chemicals company with more than a century in adhesives, alongside Stephen Industries. Lintinen went full-time this year. The next step is a pilot plant.

Worth watching, because the raw material is abundant, already separated at the mill and currently worth only its heating value, and because an adhesives manufacturer leading the round is a useful signal. The milestone ahead is consistency at volume: showing the spheres perform the same batch after batch once a pilot plant is running them at industrial rates.

Learn more: lignosphere.fi

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See you next Saturday.