By Mark Shwartz


The faux lumber is made from a new, biodegradable plastic that could be used in a variety of building materials and perhaps replace the petrochemical plastics now used in billions of disposable water bottles.      


In 2004, Billington and her colleagues received a two-year Environmental Venture Projects (EVP) grant from Stanford’s Woods Institute for the Environment to develop artificial wood that is both durable and recyclable. The research team focused on a new class of construction material called biodegradable composites, or "biocomposites"-glue-like resins reinforced with natural fibers that are made from plants and recyclable polymers.         


The hemp-PHB biocomposites are stable enough to use in furniture, floors and a variety of other building materials, he added. To degrade, it must be kept away from air, e.g., buried in a landfill, because its decomposition depends on microorganisms that live in anaerobic environments. 

"The ideal is to have nice, stable material when it’s being used," Criddle explained. "But when it’s out of use, it goes to a landfill, degrades quickly, and is reprocessed into new material that stays in a nice, stable form."

Recycling methane


"It dawned on us that there are microbes that can make PHB from methane," Criddle said. "So now we’re combining two natural processes: We’re using microbes that break down PHB plastics and release methane gas, and different organisms that consume methane and produce PHB as a byproduct." 

 It’s the ultimate in recycling, he said: "In our lab, we create conditions where only those organisms that accumulate the most plastic can reproduce. We call the process ‘survival of the fattest,’ and we have a patent application for it." 


One reason that biodegradable plastics aren’t widely used is cost. "We’re competing with polypropylene and polyethylene, two really cheap petrochemical products," Criddle said. "Most bioplastics are made using sugar from corn and other relatively expensive materials. But our process uses methane in the biogas from landfills and wastewater treatment plants, which is essentially free."    


Biodegradable bottles


In 2008, Billington and Frank were awarded a Lynn Hildemann, an associate professor of civil and environmental engineering, is collaborating on that project.

"We started with biocomposites, and now we're doing bioplastics and thinking about things that affect global warming," Criddle says. "This would never have happened without the EVP grant. There's just no way. All the right people came together, and many unexpected things came out of it."

Associate Professor Sarah Billington presents research on sustainable bio-based building materials and plastics. (23:43)