Perennial Polymers Turns City Leaves Into Biodegradable Plastic

Perennial Polymers, a biomaterials startup that launched this summer, makes biodegradable plastic from the autumn leaves that cities already collect by the thousands of tons each fall.

The company extracts lignin and cellulose from leaves, plus minerals that strengthen the material. Founder Nathan Noyes says the approach can ultimately cost less than other bioplastics because the feedstock is cheap and the process skips fermentation entirely.

"I spent the last 12 years or so in the biomaterial space, and got to see from the inside how challenging it is, largely due to the economics," Noyes said. "Two of the main reasons for that seemed to be that we were always relying on food-grade agricultural feedstock when moving away from petrochemicals, and the route to turn that into a plastic relied on fermentation, which is quite expensive."

First-generation bioplastics were made from food crops like corn and sugar. Urban leaves need no farmland to grow, and cities already have the collection infrastructure in place.

What has Perennial built so far?

Working from a lab in Delaware, the startup developed its own material after launching this summer, using a process designed to scale up easily, and it has filed provisional patents. Earlier academic research, including a study on maple leaves published in Nature Communications, informed the approach.

The formulation runs on existing industrial equipment, so manufacturers wouldn't need new machinery to make products from it.

Where could the material be used first?

One early target is agriculture. Farms lay down huge plastic sheets as mulch to suppress weeds and reduce erosion, which lifts yields but leaves microplastic waste in the soil. The films in use today can't be recycled and are often burned. A film made from Perennial's material could break down safely in the field.

"In very early testing in thin films, it looks like our material degrades in contact with soil over about two to three months," Noyes said. That pace mirrors how leaves biodegrade naturally.

The material could also go into packaging such as plastic mailers for weather-sensitive products, or other uses where plastic serves a purpose but can't easily be recycled today, Noyes says.

How big is the feedstock supply?

Large cities like New York collect thousands of tons of leaves each fall. Much of it gets composted, but EPA data suggests nearly a third ends up in landfills, where leaves can't easily break down. Perennial wants to plug into existing urban leaf collection systems, and a municipal partnership is already in the works even though the company launched only a few months ago.

Waste from the forestry industry and other natural materials could also feed the process, widening the supply base beyond city leaves.

Perennial is now scaling up to test the material with customers and aims to commercialize the bioplastic in 2027 — a timeline that will test whether leaf-based feedstock can beat food crops on cost where earlier bioplastics failed.

By Amara Osei