Chalmers researchers turn grass and clover residue into textile fibers

Chalmers University of Technology said on 8 October 2026 that its researchers and collaborators had made textile fibers and a small knitted sample from grass and clover processing residue. The work, carried out at laboratory scale and reported in a paper published in September 2025, shows a possible use for material left after protein extraction. It does not establish that clothing made this way can be produced commercially or with lower environmental impact.

How grass-clover residue became a textile fiber

The starting material is press cake, the fibrous solid remaining when soluble leaf protein is extracted from grass and clover. It contains cellulose, which can be processed into textile fibers. In its account of the work, Chalmers says its team produced dissolving pulp from that residue, then worked with collaborators at Aarhus University and the Swedish School of Textiles in Borås to spin fibers and knit a small fabric sample. That sample demonstrates that the pulp can be used for a textile process; it is not evidence of a finished commercial garment.

Chalmers associate professor Diana Bernin explained the attraction of this feedstock in terms of extraction. Cellulose is the same substance whether it comes from a tree or grass, she said, but grass has a structure from which it is easier to extract. She said the team could use simpler chemistry and smaller amounts of chemicals than are needed to extract fibers from wood. Those process observations do not, on their own, establish the overall resource use of industrial textile production.

The 2025 paper, published in ACS Sustainable Chemistry & Engineering, describes several potential outputs from the same green-biorefinery residue. Its authors investigated chlorophyll pigment extraction and soda pulping of press cake, producing cellulose-rich pulp that approached 90% cellulose by weight. They also identified lignin as another stream. Taken with the earlier protein extraction, they presented the work as a proof of concept for four potential value streams from the biomass, rather than as an operating commercial process.

Why press cake is being studied

The work addresses a practical question for green biorefineries: what to do with the solid material left after extracting plant protein. Chalmers says its group has previously studied other agricultural residues, including wheat straw and oat husks. It places the grass-clover work alongside wider efforts to make more use of harvested plants. The group's textile research was not formally part of the Swedish-Danish Green Valleys project described in the Chalmers account; it is continuing cellulose work through the follow-on Land2Value project.

A separate research team had already examined another use for grass-clover press cake. In a 2023 study, researchers tested liquid-hot-water pretreatment and enzymatic hydrolysis to produce fermentable sugars, rather than textile fibers. They treated press cake at 180–200°C for five to 10 minutes and identified 190°C for 10 minutes as the best condition among those tested. Their feedstock came from a grass and red-clover mixture harvested in Denmark in 2021. The result provides context for interest in the residue, but its measurements should not be transferred to the Chalmers textile material.

What remains before grass fibers could become clothing

The environmental case remains open. Bernin told Chalmers that benefits for resources and the environment need further investigation because a laboratory process is difficult to compare fairly with industrial production. She identified pilot-scale testing and a comparison with a large-scale process as next steps. The 2025 paper also notes that silica in nonwood biomass can complicate chemical recovery and combustion. Its discussion of recovering silica before lignin describes a possible approach, not a result demonstrated by this experiment.

The team also has feedstock questions to resolve. Bernin said it needs to assess different grass types and determine how press cake should be stored before processing, including whether it should be dried or frozen. The reported pulp, fibers and knitted sample establish that the material can pass through key textile-making steps in a laboratory. They leave open how consistently those steps would work at larger scale, how the resulting fibers would perform in use and whether the process would offer a measurable advantage over established alternatives.