Food Waste Becomes Climate Tool as Researchers Develop Low-Energy Direct Air Capture Breakthrough
Researchers have developed a new method for capturing carbon dioxide from the atmosphere using waste products from the food industry, offering a potentially lower-energy and more sustainable alternative to existing direct air capture technologies.
The approach, developed by scientists working in materials science and chemical engineering, uses by-products from dairy and soy production such as whey and tofu waste to create protein-based materials capable of binding carbon dioxide from ambient air. The work aims to address one of the key challenges in carbon removal: the high energy demand and cost of conventional capture systems.
Direct air capture technologies are increasingly seen as an important part of global climate strategies, but most existing methods rely on energy-intensive chemical processes that limit scalability. The new research suggests that food industry waste streams could provide a widely available and low-cost feedstock for carbon capture materials.
The method involves extracting proteins from waste liquids generated during cheese and tofu production, which are then processed into microscopic structures known as amyloid fibrils. These fibrils are combined with potassium hydroxide and formed into porous beads that act like sponges, absorbing carbon dioxide when exposed to air.
Once in contact with the atmosphere, the potassium hydroxide reacts with carbon dioxide to form hydrogen carbonate compounds, effectively removing the gas from the air. Laboratory tests showed that one gram of material could capture up to 97 milligrams of carbon dioxide, a level the researchers say is higher than many conventional direct air capture systems.
The work is linked to research at the Swiss Federal Institute of Technology in Zurich, commonly known as ETH Zurich, where scientists have been exploring bio-based materials for environmental applications. The team reports that the system can be regenerated using a mild acid and base treatment at room temperature, allowing the carbon dioxide to be released and collected without the need for high heat or vacuum systems typically used in existing technologies.
This low-energy regeneration process is a key feature of the approach, as it significantly reduces the operational energy requirements associated with carbon capture. Researchers also report that the protein-based beads remained stable through multiple capture and release cycles during laboratory testing.
A further advantage highlighted by the researchers is the circular nature of the material. Because the system is based on organic, food-grade components, it is non-toxic and biodegradable. At the end of its useful life, the material could potentially be repurposed as fertiliser or converted into biofuel, reducing waste and supporting circular economy principles.
The study also suggests that the environmental footprint of the process could be lower than that of many existing direct air capture technologies, although further analysis is needed to confirm performance at industrial scale. Current experiments have been conducted at laboratory scale using only small quantities of material, capturing tens of grams of carbon dioxide in controlled conditions.
Researchers involved in the project say scalability remains the key challenge, particularly in scaling production of the protein beads and integrating the system into large-scale carbon removal infrastructure. However, they argue that the use of widely available food waste streams could make large-scale deployment more feasible than approaches requiring specialised synthetic materials.
While cost estimates have not yet been finalised, the research team expects the method to be significantly cheaper than conventional direct air capture due to its low energy requirements and reliance on existing waste resources.
As governments and industries increasingly explore large-scale carbon removal strategies to meet climate targets, the development highlights growing interest in nature-based and bio-derived technologies that combine waste utilisation with atmospheric carbon capture. If successfully scaled, the approach could offer a new pathway for low-energy carbon removal integrated into a circular economy model.
