by Greg Stevens
Today I read an article called Cheese byproducts and bioplastic film packaging about a new packaging material that is biodegradable and made from whey protein. I want to commend this effort, and I think it is a fantastic advance in bioplastics and the materials industry. The fact that it is water-proof enough to be used in food containers, but that the material breaks down in water with the simple addition of enzymes, is especially promising. This material deserves serious attention and kudos.
But…There is something wrong with the article.
There is a sentence, right at the center of it, that is misleading (at best) or incorrect (at worst).
As a student of bioplastics, and if you have been reading this website, you should be able to spot it. Can you?
The sentence in question is this: “This new plastic is made using whey protein, which means it is biodegradable.”
In an earlier article, Shades of Green, we talked about a product called “green polypropylene” which is made from sugar cane, but after the manufacturing process is complete the final polymer molecule is identical to traditional plastics in every way. As a result, it is not biodegradable. It is made from sugar cane, but because of the way that it is processed, the way it reacts in the environment is just as “unnatural” as traditional plastics.
By contrast, one of our featured articles, What’s in the word Biodegradable?,talked about a technology used by ENSO bottles: an additive that can be added to traditional plastics to make them biodegradable. The plastic used by ENSO bottles is biodegradable, but is not made from renewable resources. It is, in some ways, the opposite of “green polypropylene”: non-renewable resources, but it does biodegrade.
This distinction between degradability and renewability is important: these are two components of being “green” that are completely independent of one another. And yet a lot of advertisers, promoters, and people in the media would like us to believe that because a product is one, it therefore must be the other. Or they will simply call it “bioplastic” because it is biodegradable, and keep hush-hush and let you assume that it is made from renewable resources whether it is or not. (Or they may do the reverse.)
In the case of the cheesy bi-product plastic described in the main article, it is honestly both: it is biodegradable, and it is made from renewable resources. But by leaving in the cheesy claim “…is it made from whey protein, which means it’s biodegradable” they are just re-enforcing this mistaken belief, and making it easier for other groups to mislead consumers in the future.