That's a Corn Cup?!

Last month, we took a look at the "new" bottles by Coke and Heinz that are partially made from plants. What we learned is that the way these natural materials are processed, they are turned into plastic.

This month, we are taking a look at PLA or polylactic acid products. PLA is made from natural starches like corn, sugarcane or potatoes. The sugarcane, corn and potatoes are harvested, processed to yield sugar, and then the sugar is fermented by bacteria to form lactic acid. The lactic acid is then blended into polymers that create the PLA. While potatoes and sugarcane can be a feed stock source for lactic acid, in the United States, a majority of the source is corn.

The way the polymers are formed, the PLA creates a plastic like material but unlike the polyethelyne terepthalates (#1 PET), the PLA breaks down when exposed to high temperatures. Because the PLA can be broken down by microbes and bacteria, they are biodegradable. For them to fully break down, however, they need to go to commercial composting facilities like GreenCo in Barnsville or Wilbros, LLC Composting Facility in Toccoa. If you put them in your backyard composting system, it will take a really long time for these products to break down – if they ever do.

Good things about PLA

- By making products out of these natural products, it helps reduce our dependence on foreign oil

- It allows us to use petroleum for higher use needs like transportation - The production of PLA results in less greenhouse gases than when manufacturing the more traditional types of plastics.

- If properly handled, they breakdown and become compost.

Objections to PLA

- Much of it is made from genetically modified corn

- The use of corn for products vs. food is of concern

- Corn requires petroleum based fertilizers for growing

- If PLA products are not captured from the waste stream to be composted, they become waste and just add to the landfills.

A great resource regarding bio-degradable products is the Biodegradable Products Institute which provides information about scientifically based standards and the recovery of compostable materials. Its complicated and while PLA isn't the final answer, it will hopefully be a step on building the markets for bio-based alternatives.