What is PLA plastic?




Have you noticed the different new “green” bags in your supermarket or grocer? They claim to be 100% compostable and biodegradable.

Most of them are made from PLA, a bioplastic. Bioplastic is a new type of plastic generally made from plant starch or sugars, and not from petroleum. Having the name BIO in the plastic can be a bit misleading since they don’t just biodegrade like a banana peel.

So is PLA really compostable?

The short answer is YES! But the plastic is only compostable if you bring it to an industrial composting facility that accepts PLA plastic, and there aren’t that many.

what is PLA plastic

So are the companies just straight up lying to us?

Let’s take a look at the definition.

  1. Biodegrade – break down into carbon dioxide, water, biomass at the same rate as cellulose (paper).
  2. Disintegrate – the material is indistinguishable in the compost, that it is not visible and needs to be screened out.
  3. Eco-toxicity – biodegradation does not produce any toxic material, and the compost can support plant growth.

Biodegradable Plastic is plastic which will degrade from the action of naturally occurring microorganism, such as bacteria, fungi, etc. over some time. Note that there is no requirement for leaving “no toxic residue,“ and as well as no requirement for the time it needs to take to biodegrade. This can actually take between 100 – 1000 years. Not helping the environment at all.

Degradable Plastic is plastic which will undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties.  Please note that there is no requirement that the plastic has to degrade from the action of “naturally occurring microorganism” or any of the other criteria required for compostable plastics. A plastic, therefore, may be degradable but not biodegradable, or it may be biodegradable but not compostable (that is, it breaks down too slowly to be called compostable or leaves toxic residue).

What is PLA?

PLA or Polylactic Acid is mainly made from genetically modified cornstarch, which is so kindly being produced by NatureWorks, a subsidiary company from Cargill, the biggest producer of modified corn in the world.

what is PLA plastic

Sound like conspiracy here.

READ on…

PLA is made from a “renewable” resource, not petroleum, and when incinerated, it will only leave carbon dioxide and water behind. That’s great news, right???

BUT…It requires an industrial composting facility where a cocktail of microorganisms is continually being fed, and a temperature of 60 C is required for 10 days. It also needs the right amount of moisture and oxygen to degrade in 3 – 6 months. 

In a properly engineered landfill, nothing is meant to degrade. No bag – reusable or conventional plastic shopping bag – will decompose in a landfill. Which actually helps the environment by not producing dangerous greenhouse gases like methane. *

In fact, your compost wouldn’t even get to the desired temperature of 60 degrees Celcius or 140 Fahrenheit. The standard home compost reaches a maximum of 43- 48 C, or 110 – 120 F.

It is not recommended to put these PLA biodegradable plastics into your home compost, they might remain there for 100 – 1000 years. 

Where does my “PLA biodegradable plastic bag” go?

You probably think you are doing a good thing for the environment by buying a green bag that claims to be biodegradable and compostable.

Fair enough, the companies make them look green and pleasant, and the advertisement is simply misleading. Yes, they degrade but only at an industrial composting facility. In the US, there are only 113 of them.

See if you can find one in your area by going to find a composter.

I am currently residing in Quebec, and I found 2 facilities in all of Quebec province. TWO facilities for all of Quebec province???

Our local Metro Supermarket hands out 15000 plastic bags per week, and that doesn’t include the fruit and vegetable bags. Who can handle these amounts of waste?

The other problem we find with PLA is, people often think it is recyclable, just like our standard plastic, and therefore it ends up in the same bin. This misconception causes lots of problems in the plastic recycling world as your PLA products to act as a contaminant in hydrocarbon-based resins such as PE, PP, PET, and PS. 

It costs millions each year for recycling facilities to sort through the different plastics since PLA looks very similar to standard plastic, and the machines can’t identify the difference yet. 

What’s the alternative?

what is PLA plastic

So far, the best solution we have is to minimize our use of single-use plastics overall. Bring your green shopping bag to the grocer, and if you like using straws, consider swapping to natures Straw.

Here are some more tips for you to minimize the use of single-use plastic.

We don’t have a way to dispose of PLA products properly. Buying items that are not heavily packaged in plastic is a good alternative. We have to become aware of the fact that most bioplastics aren’t good for the environment either.

Let’s help and spread the word. We know there are alternatives out there, most of the time, it is just a question of educating yourself and your friends to make better decisions. I hope you can walk away from this article with some more knowledge about different types of plastics.

Feel more confident in the way you shop and stay healthy and happy.

Yours Hendrik


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Hendrik Kaiser

I've studied biology and lived for 3 years on an off-grid permaculture farm. I love kitesurfing and keeping my body healthy and fit. Hence, I care so much about keeping our environment clean and being as zero waste as possible. Being a zerowasteman is a superpower everyone has inside of themselves, and I want to teach you how you can unleash it.

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