TECH

From tough plant waste to everyday products, this light-powered advance opens a path to greener plastics.

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 in 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 utilized in the food, cosmetics, and chemical sectors.

Crucially, the innovation ensures the complete, zero-waste utilization of the raw material. "The lignin fragments that remain after the extraction process have been used for the first time as biodegradable plasticizers that can be processed via 3D printing," highlighted Dr. Guijarro.

This image depicts a photocatalytic reactor developed by researchers at the University of Alicante (UA) and the Polytechnic University of Valencia (UPV)

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 toward 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.

Capturing Light… “In this study, we present a technology that allows us to transform lignin into high-value-added products using only light and ambient conditions,” explains the lead researcher, Néstor Guijarro. Specifically, the photocatalyst is capable of capturing light and using that energy to selectively fragment the lignin. “We have also integrated this system into a flow reactor, which allows us to carry out the process continuously, efficiently, and on a scalable scale,” adds the UA researcher.

As a result, after processing the lignin, they obtained vanillin as the main product, the molecule responsible for the aroma of vanilla, with a record yield of 7.1% by weight, which is equivalent to extracting 94% of all the aromatic monomeric units. This organic substance is in high demand in the food, cosmetic, and chemical industries.

Another advantage of this innovation is the comprehensive utilization of the generated waste. “The lignin fragments remaining after the process have been used for the first time as biodegradable plasticizers that can be processed using 3D printing,” Guijarro points out.

Laboratory tests...The tests carried out in the laboratory show that these additives improve the flexibility, strength, and shape memory of the material without compromising its processability. In fact, the researchers have printed objects such as a biodegradable mobile phone case with the same functionalities as the standard ones.

This work, the UA researcher notes, “represents a significant step towards the comprehensive utilization of lignin and lays the technological groundwork for the development of a new generation of more sustainable, efficient, and value-oriented biorefineries, in line with European objectives for ecological transition and a circular economy.”

High-performance green plasticizers...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 Center 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 plasticizers. These were tailored for polylactic acid (PLA), one of the most widely adopted biopolymers in industrial manufacturing.

"We repurposed the by-product to plasticize 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.

A pioneering light-powered technology converts lignin (a rigid polymer making up 30% of plant biomass) into vanillin and biodegradable plastics. Developed by the University of Alicante and Polytechnic University of Valencia, this innovation uses an affordable anthraquinone photocatalyst under ultraviolet light to bypass traditional fossil fuels.

The process offers a highly sustainable method for repurposing tough plant waste:

The challenge: Lignin’s highly complex chemical structure has traditionally been one of the biggest hurdles in biorefineries.

The catalyst: Researchers use an affordable, highly stable anthraquinone photocatalyst.

The mechanism: When activated by UV light, the catalyst selectively breaks the most abundant bonds within the lignin.

The Output: It successfully transforms the stubborn plant waste into vanillin and precursors for biodegradable materials.

Provided by University of Alicante