A pioneering technology capable of converting lignin, one of the world's most abundant organic compounds, into vanillin and biodegradable materials has been unveiled by the University of Alicante (UA), in collaboration with the Polytechnic University of Valencia (UPV). The study, published today in the prestigious journal Nature Communications, offers a sustainable method for repurposing plant waste and identifies viable alternatives to the fossil fuels that currently drive the chemical industry.
Lignin is a complex organic polymer that constitutes nearly 30% of plant biomass. Due to its intricate chemical structure, it has long been one of the greatest unresolved challenges for biorefineries. Conventional processing methods typically yield highly heterogeneous mixtures that are notoriously difficult to separate and refine.
To overcome this, the UA-led team developed an innovative photocatalyst based on anthraquinone—an affordable and highly stable material. When activated by ultraviolet light, this catalyst selectively breaks down the most abundant chemical bonds within lignin.
“In this study, we present a technology that allows us to transform lignin into high-value products using nothing but light and ambient conditions,” explained Dr Néstor Guijarro, the study’s principal investigator. The photocatalyst captures light and harnesses that energy to split the lignin selectively. “Furthermore, we have integrated this system into a flow reactor, allowing the entire process to run continuously, efficiently, and at a scalable level,” the UA researcher added.
The process yields vanillin—the primary molecule responsible for the aroma of vanilla—as its main product, achieving a record weight yield of 7.1%. This is equivalent to extracting 94% of all available aromatic monomer units. Vanillin is a highly sought-after organic substance heavily utilised in the food, cosmetics, and chemical sectors.
Crucially, the innovation ensures the complete, zero-waste utilisation of the raw material. “The lignin fragments that remain after the extraction process have been used for the first time as biodegradable plasticisers that can be processed via 3D printing,” highlighted Dr Guijarro.
Laboratory trials demonstrate that these sustainable additives significantly enhance the flexibility, strength, and shape-memory performance of the bioplastics without compromising their workability. To prove its real-world viability, the team successfully printed fully functional consumer items, including a biodegradable mobile phone case with the same durability and properties as conventional plastics.
According to the authors, the research represents a major leap forward towards the comprehensive commercial use of lignin. It establishes the technical framework for a new generation of sustainable, high-value biorefineries, directly aligning with European green transition and circular economy mandates.
High-performance green plasticisers
Led by the University Institute of Electrochemistry at UA, the international study also features contributions from the University Institute of Materials Technology (IUITM) at UPV, the VTT Technical Research Centre of Finland, and the University of Salzburg in Austria.
The team at the UPV’s Alcoy campus focused specifically on converting the post-process residue supplied by UA into high-performance, renewable, and biodegradable plasticisers. These were tailored for polylactic acid (PLA), one of the most widely adopted biopolymers in industrial manufacturing.
"We repurposed the by-product to plasticise PLA, unlocking fascinating properties such as shape memory, enhanced flexibility, and seamless integration into additive manufacturing," said Professor Rafael Balart, a senior researcher at IUITM-UPV.