Covestro has launched Bio4PURConti, an EU-funded project aimed at developing the world’s first continuous production process for bio-based aniline.
Aniline is a key raw material for the plastics and chemical industry, particularly in the production of MDI, or methylene diphenyl diisocyanate, which is used in polyurethane value chains. Polyurethanes are widely used in insulation, automotive components, furniture, coatings, adhesives, elastomers, and industrial applications.
Covestro is coordinating a 10-partner consortium across seven countries. The project will move from laboratory work toward semi-industrial demonstration at Bio Base Europe Pilot Plant in Ghent and Covestro’s site in Leverkusen, with work targeting a 1.5 cubic metre demonstration scale.
The production route uses plant-based sugars, including sugars derived from hardwood biomass, as renewable feedstock. A tailored microorganism converts the sugars into an intermediate product through fermentation, before chemical catalysis converts that intermediate into aniline with fully plant-based carbon.
Bio4PURConti is intended to move beyond fed-batch production, where raw materials are added and product is harvested in stages. The project targets continuous fermentation, cell recycling, real-time analytics, and downstream processing, aiming to improve process efficiency and support industrial scale-up.
Defossilisation reaches the process route
The chemical industry’s decarbonisation challenge is often framed around energy use, although feedstock carbon is equally important. Many essential industrial chemicals are still derived from fossil resources, and their downstream value chains are deeply embedded in manufacturing. Replacing those inputs requires processes that can work with existing specifications, plants, and customer applications.
Covestro’s drop-in approach gives the project much of its industrial interest. Bio-based aniline that meets existing MDI specifications could enter polyurethane value chains without forcing downstream users to redesign materials, equipment, or product qualification processes. The value of a lower-carbon intermediate rises sharply when it can be substituted without destabilising the rest of the production system.
Continuous production also changes the engineering challenge. Fermentation processes can be difficult to operate continuously because microorganisms, feedstocks, contamination control, product inhibition, and downstream separation all have to remain stable over time. Adding catalytic conversion creates another layer of process integration, where biological and chemical steps have to be matched in throughput, quality, and reliability.
Real-time analytics will be central to that transition. A continuous process cannot rely only on periodic laboratory testing if it is to maintain product consistency and respond quickly to process drift. Sensors, process analytical technology, control algorithms, and operator intervention strategies all become part of the scale-up.
The project sits alongside a wider industrial shift toward lower-carbon process inputs, energy efficiency, and better utility management. Factory utility systems are already being re-examined through work such as compressed air energy checks, which target waste, reliability, and carbon impact in established production environments. Bio-based chemicals address the feedstock side of the same pressure.
Polyurethane users face rising scrutiny over embedded carbon in insulation materials, automotive parts, construction products, and industrial components. Chemically equivalent materials with lower fossil carbon content would give suppliers a stronger route to credible reductions beyond energy purchasing and offset claims.
Cost and scale remain difficult. Bio-based routes must compete with mature fossil-derived processes that have benefited from decades of optimisation, large asset bases, and integrated supply chains. Scaling fermentation and catalysis to industrial volumes will require productivity, feedstock consistency, downstream efficiency, and quality assurance strong enough to withstand commercial pricing pressure.
Bio4PURConti targets one of the more important questions facing process manufacturers: whether renewable carbon can be introduced into large industrial value chains without asking every downstream user to rebuild their process. If the continuous route works at scale, bio-based aniline will move from technical possibility toward industrial infrastructure.
