Cotton waste and fungi combine to create biodegradable packaging

Scientists at the US Department of Agriculture (USDA) have developed agricultural waste blends which can be used in a process that literally grows custom packaging products, providing a cost-effective and green alternative to extruded polystyrene foam packaging.

The process involves combining cotton gin waste and fungi inside a cast, called a ‘tool’. The fungus grows onto, in and around the cotton waste, eventually forming a new, consistently textured, solid mass.

Once the tool is opened, the custom-shaped mass emerges - a spongy-looking material similar in appearance to polystyrene foam. After being put into a kiln-like oven, where the live fungi are killed, the result is a material that is biodegradable, compostable and flame-retardant but has the cushioning strength of synthetic packing material.

Biomass packaging material created using technology developed by ARS, collaborators and Ecovative can be made to custom-fit a wide variety of products. Photo by Ecovative.

The biodegradable blends were developed at the USDA’s Agricultural Research Service (ARS) Cotton Production and Processing Research Unit by engineer Greg Holt and his colleagues at Lubbock, Texas. Hunt’s industry partner, Ecovative Design, developed the patented method that uses fungi as a workhorse.

To learn which blends meet or exceed the same characteristics of extruded polystyrene foam, Holt’s lab evaluated the physical and mechanical properties of six different cotton by-product blends as a substrate for the fungal colonisation. Each blend was inoculated with a single fungus using two different inoculation methods for a total of 12 treatments that were evaluated for numerous physical and mechanical properties.

The results of the study, published in the Journal of Biobased Materials and Bioenergy, indicated that there were indeed blends which met or exceeded the characteristics of the foam. The blend and inoculation method needed were based on the end use of the product.

Ecovative Design is now selling the packaging parts to its corporate clients - including Dell, Steelcase, Crate & Barrel and others - where they will be used to protect computers and other breakables during shipping.

Credit: USDA/ARS