Gas fermentation to chemicals

01Overview and value chain#

Markers EC: US EPA Renewable Fuel Standard (D3/D7 cellulosic RINs) + EU RED III Recycled Carbon Fuels (Art. 27) + China national biofuel programme | OECD: Industrial biotechnology, Bioenergy, Carbon management | Regulator: EPA (USA), ECHA/REACH (EU), NEA (China)

This article covers the operators that run gas fermentation to convert steel-mill and refinery off-gas — carbon monoxide, carbon dioxide and hydrogen — into ethanol, acetone, sustainable aviation fuel (SAF) and other chemicals, using acetogenic bacteria that fix one-carbon gases into acetyl-CoA through the Wood–Ljungdahl pathway. It is bounded against two sibling articles: Gas fermentation of food protein owns hydrogen-oxidising bacteria grown as microbial protein (Solar Foods, Air Protein, Deep Branch, Calysta, Calysseo, Unibio), and Gas fermentation reactors owns the hardware layer — the bubble-column vessels, hollow-fiber cell-retention skids and gas-cleanup trains supplied by GEA, Koch Modular, Topsoe and the Shougang-LanzaTech joint venture. Here the product is the molecule, not the biomass or the reactor. The commercial fleet is concentrated: a single Shougang-LanzaTech plant at Caofeidian ships around 210,000 tonnes/yr of recycled-carbon ethanol from steel off-gas, ArcelorMittal’s €200M Steelanol plant at Ghent ferments blast-furnace gas into ethanol with LanzaTech acetogens, and LanzaJet’s Freedom Pines Fuels facility in Soperton, Georgia — the world’s first commercial ethanol-to-jet plant — turns recycled-carbon ethanol into drop-in SAF and renewable diesel.

The key directions of gas fermentation to chemicals are:

1. Recycled-carbon ethanol from steel off-gas (Steel-Mill Ethanol): acetogens ferment cleaned blast-furnace and converter gas into fuel- and chemical-grade ethanol at commercial scale — the configuration of the 210,000 t/yr Shougang plant and the Steelanol Ghent host.
2. Alcohol-to-jet SAF (ATJ SAF): ethanol is dehydrated, oligomerised and hydrogenated into drop-in sustainable aviation fuel and renewable diesel, the route LanzaJet operates at Freedom Pines Fuels.
3. Acetone and higher alcohols (LanzaTech 2.0 strains): engineered Clostridium strains co-produce acetone and isopropanol from the same off-gas feedstock, broadening the product slate beyond ethanol into chemical intermediates.
4. Non-steel CO2 feedstocks (CO2-to-Chemicals): engineered-microbe platforms extend gas/CO2 fermentation beyond steel and refinery off-gas to industrial CO2 and carbon-bearing side-streams, the branch Cemvita pursues with its FermOil oil platform and SAF-feedstock programme.

Sectoral value chain#

[off-gas capture] ──> [gas cleanup] ──> [acetogenic fermentation] ──> [broth recovery]
                                              │
                                 (Wood–Ljungdahl: CO/CO2 + H2 -> acetyl-CoA)
                                              │
                                              ▼
[certification & offtake] <─── [chemical / SAF upgrading] <─────┘

Value chain levels#

Cross-cutting technologies of the sector:

• Wood–Ljungdahl acetogens (Acetogenic Fermentation): Clostridium autoethanogenum and related acetogens reduce CO/CO2 with H2 to acetyl-CoA through the reductive acetyl-CoA pathway, the metabolic core that lets a gas become a chemical.
• Alcohol-to-jet catalysis (ATJ): dehydration of ethanol to ethylene, oligomerisation, and hydrogenation into synthetic paraffinic kerosene (SAF) and renewable diesel certified under ASTM D7566.
• Recycled-carbon and mass-balance certification (Carbon Certification): RFS cellulosic/D7 RINs, RED III Recycled Carbon Fuels recognition, and ISCC PLUS chain-of-custody turn a waste-gas molecule into a credit-bearing, auditable product.

02US#

The United States anchors the operator side of the category: LanzaTech licenses the acetogen platform that the global commercial fleet runs on, LanzaJet’s Freedom Pines Fuels plant is the first commercial ethanol-to-SAF facility, and Cemvita extends the feedstock base beyond steel off-gas to industrial CO2 and carbon-bearing side-streams.

acetogen licensing, alcohol-to-jet SAF, CO2-utilization microbes#

• LanzaTech: the Chicago-based licensor (LanzaTech Global, LNZA) whose C. autoethanogenum platform and CarbonSmart recycled-carbon ethanol underpin the Shougang 210,000 t/yr plant, the Steelanol Ghent host and the Indian 2G/4G licence pipeline; the firm reached commercial operation under a restructuring that eased its going-concern flag after January 2026 private placements.
• LanzaJet: the LanzaTech spin-off (founded 2020) operates the Freedom Pines Fuels plant in Soperton, Georgia — the world’s first commercial ethanol-to-sustainable-aviation-fuel facility — producing drop-in SAF and renewable diesel from recycled-carbon and bio-ethanol under ASTM D7566.
• Cemvita Factory: the Houston engineered-microbe house demonstrated a 75,000-litre industrial scale-up of its FermOil microbial-oil platform on carbon-bearing feedstock and is advancing a circular SAF-feedstock programme with Radix, representing the non-steel CO2-utilization branch of gas/CO2 fermentation.

03CN#

China hosts the world’s single largest commercial gas-fermentation plant but the operator trade is concentrated in one firm: Shougang Langze (首钢朗泽, HK 02553), the LanzaTech joint venture that runs the 210,000 t/yr Caofeidian steel-off-gas-to-ethanol plant and whose recycled-carbon ethanol was listed in the national biofuel programme in 2026. The reactor and gas-cleanup engineering for that plant is covered in Gas fermentation reactors, so it is named here as the operator rather than re-tabled for hardware. A live probe surfaced no second confirmed Chinese operator of gas fermentation to chemicals at comparable scale: the domestic trade is otherwise absorbed into broad industrial ethanol and chemical-ethanol capacity rather than a distinct gas-fermentation operator segment, and Sinopec’s 2026 disclosures concern oil-and-gas production rather than gas fermentation.

national biofuel programme, single-operator concentration, broad industrial ethanol#

• Policy pull: Shougang Langze’s industrial-off-gas ethanol was formally listed in China’s national biofuel programme in 2026, the regulatory milestone that opens fuel-blending offtake for recycled-carbon ethanol.
• Operator concentration: the 210,000 t/yr Caofeidian plant is the dominant commercial reference; the operator filed for a Hong Kong listing but disclosed three years of widening net losses (gross margin around -24.5%), the commercial-economics pressure that defines the CN slice.
• Implication for buyers: procurement teams sourcing recycled-carbon ethanol from China should treat Shougang Langze as the primary commercial-counterparty and verify offtake availability, since a second specialist operator at comparable scale could not be confirmed.

04EU#

Europe’s commercial reference is ArcelorMittal’s €200M Steelanol plant at Ghent, Belgium, where LanzaTech acetogens ferment captured blast-furnace gas into recycled-carbon ethanol under the EU’s Recycled Carbon Fuels framework, though the plant’s status is under strategic review as part of ArcelorMittal’s wider Smart Carbon programme reassessment.

blast-furnace-gas fermentation, RED III Recycled Carbon Fuels, strategic review#

• Steelanol (ArcelorMittal + LanzaTech): the €200M Ghent facility is the EU’s flagship waste-gas-to-ethanol host, converting steelworks blast-furnace gas into recycled-carbon ethanol with LanzaTech’s acetogen platform; the project was developed under the EU CORDIS-backed Steelanol consortium.
• RED III Recycled Carbon Fuels: EU Renewable Energy Directive III Article 27 recognises recycled carbon fuels from waste-gas streams, the regulatory channel through which Steelanol ethanol can enter the transport-fuel pool — the same mechanism that frames the investment case for waste-gas fermentation in Europe.
• Strategic review 2026: the Ghent project’s future is under review alongside ArcelorMittal’s broader Smart Carbon initiatives, a status buyers should weigh when treating Steelanol ethanol as a committed offtake stream.

05Leading companies and research institutes#

The operator side of gas fermentation to chemicals is led by LanzaTech, whose acetogen platform is the common thread across the commercial fleet: the 210,000 t/yr Shougang plant in China (named here as the operator, with hardware covered in Gas fermentation reactors), the €200M Steelanol host at ArcelorMittal Ghent, and the Indian licensee pipeline. India is carried by LanzaTech licensees rather than a domestic operator: Sustainable Enterprises Enterprises (SED) is developing a ₹150 crore second-generation ethanol biorefinery in Uttar Pradesh under the PM JI-VAN scheme with LanzaTech gas-fermentation technology, and Jakson Green is supplying NTPC a fourth-generation (4G) ethanol facility on the same platform. The protein-from-gas operators (Solar Foods, Air Protein, Deep Branch, Calysta, Calysseo, Unibio) are tabled in Gas fermentation of food protein and are excluded here, as are the reactor and gas-cleanup hardware vendors (GEA, Koch Modular, Topsoe).

06Tech stack and innovations#

The stack rests on three platforms: an acetogen strain that turns gas into acetyl-CoA, a catalytic upgrading step that turns ethanol into drop-in fuels, and a certification layer that turns a waste-gas molecule into a credit-bearing, auditable product.

1. Acetogen strain platform (Wood–Ljungdahl):
   • Clostridium autoethanogenum and engineered derivatives reduce CO/CO2 with H2 to acetyl-CoA through the reductive acetyl-CoA (Wood–Ljungdahl) pathway, then channel it to ethanol, acetone and isopropanol; LanzaTech’s second-generation strain programme (LanzaTech 2.0) shifts the product slate from ethanol-only toward acetone and higher alcohols.
   • case: the same acetogen platform runs the Shougang 210,000 t/yr ethanol plant and the Steelanol Ghent host, the two largest commercial references in the sector.
2. Alcohol-to-jet and chemical upgrading (ATJ Catalysis):
   • ethanol is dehydrated to ethylene, oligomerised, and hydrogenated into synthetic paraffinic kerosene (SAF) and renewable diesel under ASTM D7566 Annex A5, or routed to ethanol-to-ethylene (EtE) for polymer intermediates.
   • case: LanzaJet’s Freedom Pines Fuels plant is the first commercial deployment of the ATJ route at scale, taking recycled-carbon and bio-ethanol to drop-in SAF.
3. CO2-utilization microbial platforms (CO2-to-Chemicals):
   • engineered microbes extend the feedstock base beyond steel and refinery off-gas to industrial CO2 and carbon-bearing side-streams such as crude glycerin, producing microbial oils and SAF-feedstock intermediates.
   • case: Cemvita’s 75,000-litre FermOil scale-up and its Radix circular SAF-feedstock collaboration represent the non-steel branch of gas/CO2 fermentation.

07Value chains and production pipelines#

Industrial pipeline of an off-gas-to-chemicals gas-fermentation plant (EPA RFS / EU RED III / ASTM D7566)#

┌───────────────────────────┐      ┌───────────────────────────┐
│ 1. Off-gas capture        │ ───> │ 2. Gas cleanup            │
└───────────────────────────┘      └───────────────────────────┘
                                                  │
                                                  ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 4. Broth recovery         │ <─── │ 3. Acetogenic fermentation│
└───────────────────────────┘      └───────────────────────────┘
              │
              ▼
┌───────────────────────────┐      ┌───────────────────────────┐
│ 5. Chemical / SAF upgrade │ ───> │ 6. Certification & offtake │
└───────────────────────────┘      └───────────────────────────┘

Stage 1: Off-gas capture

Steel-mill blast-furnace and converter gas, refinery off-gas, or engineered syngas is captured at the emitter fence-line as the carbon feedstock; the Shougang Caofeidian plant draws on Shougang Group steelworks gas and Steelanol draws on the ArcelorMittal Ghent blast furnaces.

Stage 2: Gas cleanup

The raw off-gas is stripped of tars, particulates and sulphur (H2S), and the CO:CO2:H2 ratio is conditioned to match the acetogen stoichiometry before the gas enters the bioreactor — the gas-cleanup train detailed in Gas fermentation reactors.

Stage 3: Acetogenic fermentation

Conditioned syngas is sparged through a continuous gas-loop bioreactor holding Clostridium autoethanogenum, which fixes CO/CO2 with H2 to acetyl-CoA via the Wood–Ljungdahl pathway and channels it to ethanol (and, on engineered LanzaTech 2.0 strains, acetone and isopropanol).

Stage 4: Broth recovery

The dilute ethanol/acetone broth is stripped and distilled to anhydrous fuel- and chemical-grade purity — the 210,000 t/yr Shougang plant and the Steelanol facility both output recycled-carbon anhydrous ethanol at this stage.

Stage 5: Chemical / SAF upgrading

Ethanol is either sold as recycled-carbon ethanol, dehydrated to ethylene for polymer intermediates, or routed through alcohol-to-jet catalysis (dehydration, oligomerisation, hydrogenation) into SAF and renewable diesel — the LanzaJet Freedom Pines Fuels route under ASTM D7566.

Stage 6: Certification & offtake

The product is registered under the EPA Renewable Fuel Standard (D3/D7 cellulosic RINs), certified under EU RED III Recycled Carbon Fuels and ISCC PLUS mass balance, and delivered under offtake to fuel blenders, airlines and chemical buyers — the step that turns a waste-gas molecule into a credit-bearing commercial product.