3D-Printed Coffee Ground and Mushroom Composite as a Plastic Alternative

Transforming Coffee Grounds and Mushrooms into 3D-Printable Material

Every year, Americans consume approximately 1.6 billion pounds of coffee, with over 1.1 billion pounds of coffee grounds discarded. Recognizing the potential of this massive waste, Danli Luo, a Ph.D. student at the University of Washington, developed a new formula to turn coffee grounds into a paste (Mycofluid) for 3D printing objects such as packaging materials, vase fragments, and a small statue. This paste is injected with Reishi mushroom spores, which grow on the objects to form a “mycelium skin.” This skin, a type of white fungal root system, binds the liquid components together and creates a strong, water-resistant, and lightweight material.

According to a study published in 3D Printing and Additive Manufacturing, the Mycofluid formula consists of used coffee grounds, brown rice flour, Ganoderma mushroom spores, xanthan gum (a common food adhesive found in ice cream and salad dressings), and water.

Luo also designed a new 3D printer head for the Jubilee 3D printer developed by UW’s Machine Agency lab. The new printer system can hold up to one liter of the mixture and is easily customizable for small-scale production. After printing, the objects are kept in a high-humidity environment to allow the mycelium to grow, forming a “mycelium skin” that covers the surface. This process is similar to growing home mushroom kits. However, instead of allowing the mushrooms to sprout, they are removed once the white mycelium skin forms. The researchers then dried the pieces for 24 hours, halting the mushroom fruiting process and creating a durable skin. This skin not only bonds the material together but also enhances strength, water resistance, and biodegradability, providing a sustainable alternative to Styrofoam.

The team used the printer to create various objects with Mycofluid: packaging for a small cup, three vase fragments, two halves of a Moai statue, and a two-piece coffin the size of a butterfly. The objects were then placed in a plastic chamber for ten days, during which the mycelium formed a protective shell around the Mycofluid. In the case of the statue and vase, the separate pieces even fused together.

They also conducted material tests and found that the finished product is heavier than Styrofoam, with a density closer to cardboard or charcoal. After one hour of water exposure, it absorbed only 7% of its weight in water and dried back to nearly its original weight while maintaining its shape. It is as strong and durable as polystyrene and expanded polystyrene foam, materials commonly used for Styrofoam.

Properties of Mycofluid from Coffee Grounds and Mushroom Composite

According to experimental tests, Mycofluid exhibits several advantages over traditional plastics, including:

Durability and Lightness: The material’s density is similar to cardboard or charcoal but has strength comparable to polystyrene and Styrofoam.

Water Resistance: After one hour of water exposure, it absorbs only 7% of its weight in water and can dry back to its original state without deforming.

3D Printability: The research team’s 3D printing system can create complex objects, and individual pieces can even merge together through mycelium growth.

Complete Biodegradability: Unlike traditional plastics, Mycofluid decomposes entirely without leaving behind microplastics in the environment.

Applications and Potential of 3D-Printed Coffee Ground and Mushroom Material

The research team sees widespread potential for Mycofluid, particularly in small-scale production where sustainable packaging materials are needed for fragile products like glassware. Additionally, due to its flexible shaping capabilities, this material could be used in interior design, art, and other creative fields.

Although Mycofluid has not yet been specifically tested for its decomposition rate in natural environments, all of its components are fully biodegradable. The research team is also exploring ways to expand this technology by experimenting with other food waste sources to create similar materials.

Plastic has dominated industries for decades, but with groundbreaking solutions like Mycofluid, we can envision a future where sustainable materials become the standard. Coffee not only keeps us awake every day but can also help protect the planet. Would you be willing to try a coffee-ground-based container for your cup of coffee?