Using Fungi to Replace Styrofoam

As a student at Rensselaer Polytechnic Institute, Eben Bayer, a co-founder of the company Ecovative Design and a Vermont native with some experience harvesting mushrooms, realized that perlite, a type of volcanic glass frequently used as a component of insulation, was also used in growing mushrooms.

He thought it might be possible to make insulation out of fungi using perlite – and in a class before he graduated in 2007, he proved right.

Now, the company he founded with classmate Gavin McIntyre — Ecovative Design — is angling to provide not just a mass-market, organic insulation material, but also a replacement for Styrofoam, the non-biodegradable, carbon-intense material widely used in packing and shipping.

Both are both produced through microbinding, in which local agricultural waste — including buckwheat, rice and cottonseed hulls and other materials high in lignin, a complex organic polymer found in many plants — is mixed with cells from a specific type of fungi.

Within about a week, Mr. Bayer said, the fungus digests the lignin, producing a strong biological matrix. The mixture is poured into a mold and then dehydrated, creating the finished product.

"So essentially, we use the energy locked up in the ag waste to put together a new product," says Bayer.

Jeff Stone, the editor-in-chief of Mycologia, a journal devoted to all things fungus, says, "Fungi require a source of carbon and energy like we do. In this case, what they are consuming is cellulose from plant walls, and rice hulls are predominantly cellulose."

Because Ecovative uses locally sourced raw materials and grows its products in the dark at room temperature, the company says they are less energy-intensive and cheaper to manufacture than Styrofoam.

Just how the whole process might scale up, however, remains to be seen. So far, the company has only installed a few demonstration walls using Greensulate, its insulation material. And the company is releasing limited quantities of "Acorn," its packing material, as custom-made packaging for certain Northeast manufacturers in 2009.