Are Biodegradable Plastics Good for the Environment?

Conventional petroleum based plastics make up 25% of landfills in the United States. The production of these plastics requires 200,000 barrels of oil per day. Most of the plastic products are used for packaging and containers for food transport and sale. An alternative to conventional plastics is available through a resin known as polylactic acid (PLA) or corn-plastic.

The largest producer of PLA resins is Nature Works located in Blair, Nebraska. Nature Works is owned by Cargill, the largest corn merchant in the world, so Nature Works’ PLA resin comes from corn. At the factory, corn kernels are milled and dextrose is extracted. The dextrose is fermented and lactic acid is produced as a by-product. Lactic acid can be derived from other starchy sources, such as potatoes, but Nature Works relationship to Cargill makes corn the logical choice. Nature Works converts the lactic acid to lactide and then links the lactide into long chains known as polymers. These polymers are polylactic acid or PLA.

At Nature Works, the final product is PLA resin in small translucent pellets. The pellets can be melted and shaped into containers that can be used to transport and sell food but avoid the land fills because they are biodegradable. Unlike the more common petroleum based plastic polyethylene terephthatlate (PET), PLA plastics can be composted meaning it will break down into natural compounds.