The Scoop on Bioplastics

man and child sitting on pier

The bioplastics industry has seen tremendous growth in the last few years, especially with the surge in oil prices. From plastic bottles to mobile phones, bioplastics are being used to create products typically made from petroleum-based plastics.

But with this new material comes plenty of questions.

  1. Can you eat the bottle after the liquid inside is gone? (Ok, maybe this isn’t the most serious question. But just in case you were wondering – the answer is “no!”)
  2. What number does it fall under in the plastic recycling chart?
  3. How do these plastics hold up in comparison with their petroleum pals?

Let’s answer these and dive a bit deeper with a quick bio on bioplastics.

How They’re Made

Bioplastics are made of biopolymers, derived from renewable biomass sources such as vegetable oil and corn starch. Made from naturally derived ingredients, bioplastics are essentially biodegradable, a major selling point separating them from petroleum-based plastics.

According to the Freedonia Group, a business researcher, the demand for biodegradable plastic in the U.S. is expected to expand nearly 16 percent annually to 720 million pounds in 2012. However, the industry will admit there is some work to be done. One major area to consider is recycling and composting.

How They’re Handled

Bioplastics often take the place of Polyethylene terephthalate (PET), but they aren’t compatible with this plastic resin when it comes to recycling. Bioplastics are often categorized as #7 plastic, which applies to anything that has a mixture of plastic resins.

It might seem only natural to add these bottles to your PET collection, which is accepted by many curbside programs. However, the recycling industry has had concerns that biopolymers might contaminate the PET stream. Additionally, the main issue comes in the correct identification and sorting of the plastics in the recycling process.

Because bioplastics are made of organic material, composting is another option. However, before you toss these bottles in your compost bin at home, be advised that these bottles may be difficult to compost in that environment. However, some commercial composters will accept them.

Since these plastics are biodegradable, a third option is to put them with the rest of your garbage and let them decompose in a landfill. The issue here is that landfills do not allow adequate light and oxygen for normal decomposition, so it’s unclear how long this will actually take.

Sorting Technology

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Bioplastics are being used to create an array of products, from gift cards to clamshell packaging. Photo:

A number of companies have developed systems to effectively identify and sort bioplastics so they won’t contaminate petroleum-derived plastics during recycling. The systems use near-infrared sorting to identify different polymers, as well as ultraviolet, x-ray, laser, polarized light, fluorescent light, electrostatic, melt point and other sorting techniques.

According to a mixed plastics recycling study conducted by Waste & Resources Action Programme (WRAP), Domestic Mixed Plastics Packaging Waste Options, “NIR (near-infrared) systems can effectively remove PLA bioplastic and carton board from a mixed packaging stream.”

NatureWorks LLC recently released the findings of its bioplastics recycling study, concluding that automated systems currently being used in the recycling industry are capable of sorting natural plastic bottles from petroleum-based plastic bottles with an accuracy of nearly 100 percent.

“Demonstrating that natural plastic bottles can be brought seamlessly into the recycling stream through the use of automated sorting equipment available today is a major finding and another step towards greater sustainability,” said Steve Davies, NatureWorks’ director of communications and public affairs.

The study, conducted over the past two years, surveyed equipment manufacturers that have systems able to sort biopolymers from other plastics, such as PET, HDPE, PVC and PS.

“Accurate sorting is at the heart of making recycling an economically viable business, because the recycling operation must be able to separate materials into pure streams- aluminum separated from steel or PET and HDPE plastics from other polymers,” said Davies.

Lori Brown and Trey Granger contributed to this story.

Feature image by Caleb Jones on Unsplash

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  1. Dear Earth911

    It is good that Bioplastics made from biological sources is growing, and very likely with the effort and investments spent by e.g. Dow and BASF that this will accelerate. But if the number only reaches 720 mill.(in 2012) vs. the 1 trillion tons (your number) for petroleum based (Conventional) plastics it seems we still have a job ahead of us.

    Composting is one way of Recovering material waste. Energy generation through utilising the materials energy content is another way of Recovering material waste. Whereas organic waste, as from gardens and food, is not very useful for anything more than composting, other materials like conventional plastics are best recovered through generating energy – and surely not by wasting this finite resource based material on composting ?

    Use of plastic, any type, should be REDUCED. This is particularly relevant for the consumable segment of plastics (both Bioplastics and Conventional plastics). Conventional plastic should (and can) be REUSED and/or RECYCLED. If Reused/Recycled as far as practical and then RECOVERED through energy generation, conventional plastic can be viewed very much as borrowing energy in the form of a useable material/product, and then re-inserting for energy (you will not get back the energy used to produce/transport the plastic product, but you will get the energy from the petroleum, and apparently the production and transportation energy and pollution comparisons between Bioplastics and Conventional plastics are relatively similar).

    Oxo-BioDegradable Plastic, using conventional petroleum based materials, are oxo-degradable and thereafter the oxygenated degraded short chain molecules are biodegradable (this is documented well). Whereas I believe we must continue to work to REDUCE use of plastic, especially the consumable (‘throw away’) plastic (vs. i.e. durable plastic products), to reduce waste of plastic both in land-fills and the environment, why not at the least make the consumable plastic that may potentially end up in a land-fill or in the environment oxo-biodegradable. The cost is relatively low (5% as compared to 200% for Bioplastics) and this at the least ensures that consumable plastics are biodegraded more rapidly.

    I have worked for 5 years now with adding small amounts of totally environmentally harmless additives (fatty acids and iron or manganese) to 10-300 micron thick PE and PP plastic products (from plastic bags to containers). They oxo-degrade within 3-6 months (depending on the environment, and yes – requiring oxic conditions, i.e. they cannot form Methane in anoxic conditions because they do not degrade, which organic materials, including the Biodegradable Bioplastics will, and which is apparently a much worse GHG than CO2). Scientific studies using i.e. ASTM D5338 (a standard to test for biomineralisation in standard composting conditions) demonstrate that the oxo-degraded short chain molecules from the conventional plastic with Oxo-Biodegradable additives are biomineralised (biodegraded; measured by CO2 generated [standard procedure]). The Oxo-Biodegradable conventional plastics are, as far as I know about, not ‘Compostable’ as pr. neither ASTM D6954 or EN13432, as they do not biomineralise ‘fast enough’, but then the total composting facility capacity in the US and/or EU can only account for app. 1-2% of the organic waste, and of these composting facilities only very few in fact can compost any type of plastics as they are used for garden refuse/food. And the Oxo-Biodegradable plastic still is both oxo-degradable and biodegradable, and will thus biodegrade, even if slower than in 6 months, and maybe more in time like a piece of hardwood from a tree.

    So, while we are waiting for the Bioplastics to i) be made widely available at a price we will pay and ii) not be using feed or food grade raw materials as input (these are better used to feed animals and people), then at least try to handle the current largest issue of conventional plastic waste by Reducing use, Recycling and Reusing as practical, and Recovering to energy when ‘finished’, and – if, by any chance, some plastic should end up in a land-fill or in the environment, then do make sure it will much more rapidly oxo-biodegrade through using cost-effective additives that people are willing to pay for.

    Nils B. Vogt, Dr.philos
    Siamalgamate Co., Ltd.

  2. Plastic bottles are a growing problem in our landfills and oceans. We felt that something needed to be done……and now.

    We knew that there wasn’t going to be one “fix it all” answer and began to wonder if anything was ever going to be done. The problem was growing every day, more bottles were being manufactured and more bottles were accumulating in places where we didn’t need them.

    We were wondering if “Earth Friendly Bottles” would ever be available?

    That’s why decided to do our part and started ENSO Bottles. We are partnering with other companies to offer a PET plastic bottle that will biodegrade, compost or recycle.
    Our plastic bottles can enter the normal recycling stream with regular PET plastic bottles.

    ENSO’s goal is to achieve sustainability with our plastic bottles. WE feel that ENSO plastic bottles can provide a useful service and have a positive impact on our environment.

    We all need to do our part and support recycling programs, construction of bio-reactor landfills and continue developing technology that will make plastics “Earth Friendly.”
    We’re doing those things at ENSO, we offer a plastic bottle that is earth friendly…it’s just one step in the right direction. If we all take just one step toward improving our planet….we will make a difference.


  3. By reading the article I see the upstream benefits to these products (no oil in production) but I’m still not clear on the downstream benefits. We can’t recycle them? They don’t compost well? They don’t decompose well in the landfill? Am I missing something? I realize we need to cut down on plastic use and recycle more, but I’m not clear that bioplastics are the answer. We are considering changing to bioplastics in our cafe but I’m just not sure they are the answer.

  4. Recently the safety of plastic for use in food containers and other products has come into question. While I applaud the industry for finding an alternative for petroleum-based plastics, I’m concerned that biodegradable plastics will allow these harmful polymers to be more readily assimilated into our water, our soils, and our bodies. Can you please clarify whether the plastic polymers used in bioplastics are the same as those used in traditional plastics?

  5. Association of Postconsumer Plastic Recyclers (APR)

    In order to sustain North America’s post-consumer plastic bottle recycling industry, APR encourages the production of streams of baled bottles that do not contain contaminants. APR has model bale specifications for two commercially recycled plastic bottles, PET and HDPE, listed on its website which provides guidance on bale purity. Currently, PET and HDPE bottles represent about 95% of all plastic bottles used in the United States. Bottles made of resins other than PET and HDPE are often contaminants in bales of PET and HDPE bottles.

    Until critical mass levels are achieved that allow for efficient system-wide reclamation, biopolymers may be an undesirable inclusion from a technical standpoint in both PET and HDPE bottle bales as are many bottles coded 3 through 7. Until the volume of biopolymers bottles in the commercial stream reaches critical levels that allow for economical, independent recycling operations, individual reclaiming operations are likely to be highly selective in their interest in receiving biopolymer bottles. Some reclaimers may find that processing some biopolymer bottles to sell recycled biopolymer plastic meets their business plans.

    Automatic bottle sorting equipment based on near infrared spectra can distinguish some biopolymer bottles from PET and HDPE bottles and separate the biopolymer bottles. The economics of such sorting is enhanced by high throughput and a substantial presence of the minor material, the biopolymer. Manually sorting biopolymer bottles that appear visually similar to PET or HDPE bottles containers would be problematic with regard to efficiency and accuracy.

    To date most commercial biopolymers have a density greater than 1.0 gram per cubic centimeter. Standard plastics recycling operations should separate biopolymers from HDPE, but not from PET, based on specific gravity. Biopolymers like other traditional polymers with a density greater than 1.0 g/cm3, should not be a technical issue to HDPE reclaimers, but would create a yield loss with some economic impact. Hazing of clear PET resin is expected if the concentration of at least some biopolymers exceeds approximately 0.1%. Biopolymers could be a technical problem and economic impact for PET reclaimers.

    APR encourages all plastic bottle designers and decision makers to examine the APR “Design for Recyclability Guidelines” at its website, APR continues to work with biopolymer manufacturers to identify and understand the impacts of biopolymers on the recycling of other bottle materials.

    APR encourages discussions on one biopolymer, PLA or polylactic acid, be conducted with NatureWorks LLC, a PLA provider and an APR member, to identify and understand the impacts of PLA on the recycling of other bottle materials. NatureWorks can be contacted at its website,

  6. would it not be cheaper to just have the more common plastics that are recyclable be used instead. 1–2 are more stable any way and if we can get to a point where we are recycling most or all of the plastic packages than we will save more energy than if we were to have to spend money on the machines to identify other plastics and natural resources. this is kind of counter productive.

  7. I would love to see a comparison of energy consumed and pollutants generated in the production processes related to petroleum-based plastics and bioplastics. Is this information available?

  8. How can we start a petition that we can send to the Federal Government to start to regulate the ‘one-off’ plastic usage. This can range from picnic plates and cups to the trays for meat in supermarkets. We all know the plastic packaging found in supermarkets and department stores could be made of corn starch or cellulose by products. We are beginning to see packing peanuts being replaced by corn starch. Most styrofoam should be able to be replaced as well in packaging.

    In order to make change, there needs to be some form of regulation to expect biodegradable ‘plastic’ replacements.

    How can we do this together and get people aware that the materials are available but we need to regulate this.

  9. It is in the best interest if the recycling facilities to suppress the use of bioplastic – they stand to lose lots of money. Kudos to NatureWorks for their research and proof that the number one argument of the recyclers is invalid.

    I would love a ban to prohibit the use of oil based plastic to produce any item that is deemed “disposable”. I’m sad that even items that are “earth friendly” and “biodegradable” are wrapped in ugly oil based plastic.

    Did you know we use 300,000 barrels of oil EVERY DAY to wrap the products we use in the US in plastic? Plastic around paper towels, toilet paper, and all those other things we just take off and throw into the garbage. I dare you to stand at the end of an aisle in the grocery store and look down and count the number of items you see that are wrapped in the non-renewable, oil based stuff. Think about how many of our soldiers have died protecting that precious oil so we can wrap our toilet paper in it. Oil based products have a cost that should not simply be measured in dollars.

    The best way to promote responsible production and packaging is to insist that the products you buy and use are truly earth friendly – from the inside to the outside. If 300 million people insist that what they use is responsible, manufacturers will supply that demand.

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