From Kernels to Cups

The Coca-Cola Company recently introduced the PlantBottle (along with other manufacturing companies).

The PlantBottle is advertised as the first PETE bottle that is produced partially from plants. A plastic bottle made partially from plants left my mind boggled. Can this product be better than a commodity PETE bottle?

The corncob pipe was a fashion statement that best fit Frosty the Snowman, until now.

While the corncob pipe might not be showing up at retailers, corn is showing up in the production of more everyday items. What looks like normal oil-based plastic at first glance is actually polylactic acid (PLA) plastic made from specially processed crops. That's right CORN plastic.

You can drink coffee out of it, put groceries in it, wear it and more. The point here is corn is turned into a plastic that avoids petroleum. Like corn ethanol, corn plastic allows us to make a comparable product out of a renewable resources, as opposed to oil reserves that will one day run dry. Corn can also be grown throughout the world.

So, how is cor­n plastic manufactured? First, the harvested corn crop is soaked and ground so that the endosperm can be separated from the gluten and fiber. This step is typical in grain crop harvesting as well.

Next, producers add enzymes to the starchy endosperm, which converts the endosperm into a simple sugar called dextrose. Then, the addition of bacterial cultures causes the sugar to ferment into lactic acid in the same way brewers use fermentation to produce beer.

The resulting acid consists of lactide molecules, which bond into long chains called polymers. At the end of this process, bioplastics producers have pellets of polylactic acid plastic, which can then be spun off into fibers or melted to take just about any form.

What could be wrong with a renewable resource you grow in a field and compost when you're done with it? Once these corn or bioplastics are ready to be reycled, they need to spend a month or two in a high-humidity composting environment at about 140 degrees Fahrenheit. Otherwise, these bottles will last just as long as any commodity plastic (PE and PETE).

If commercial composting isn't available, PLA plastics can wind up following with commodity plastics into the landfill or into plastic recycling programs.

What's wrong with putting corn plastics in your recycling bin? To the uninformed eye, one may look very much like the other, but their chemical composition is very different.

In fact, a relatively small amount of bioplastic can contaminate commodity plastic recycling, preventing the salvaged plastic from being reused and stopping recycling companies from profiting from recyclables.

So, unless commercial composting is available in your area. The PlantBottle is not much better than the commodity plastic bottle.

But it's a start!