Biodegradable Plastic Guide: Explore the Pros, Cons, and Uses

Biodegradable plastic (or biodegradable polymer) is a synthetic compound that can decompose over time through living organisms, eventually breaking down into water, carbon dioxide, and leftover material called biomass. Biodegradable plastic’s ability to naturally degrade within an organic time frame makes it unique from other plastics, which can take hundreds or thousands of years to break down. There are several recognized types of biodegradable plastics, including Polyhydroxyalkanoates (PHAs), Polylactic acid (PLAs), plant starch blends (like corn starch), and cellulose-based plastics.

There are a few notable differences between biodegradable plastic, bioplastic, and compostable plastic:

• Biodegradable plastic refers to any plastic that can degrade naturally through living organisms, regardless of the original material from which it derives. Plastic can be biodegradable without being a bioplastic or being considered “compostable plastic.”
• Bioplastic is a term that describes any plastic made from renewable raw natural materials. While some bioplastics are biodegradable or compostable, many of them are not, meaning they won’t break down even though they’re made of natural materials.
• Compostable plastic is a term that describes plastics that need specific conditions to break down, rather than the less complex conditions of biodegradable plastics. While biodegradable plastics can break down in a more natural environment, compostable plastics usually require industrial composting facilities.

In general, biodegradable plastics take between three and six months to decompose when left exposed to oxygen or light. Regular plastics can take up to 1,000 years to reach the same levels of decomposition.

Biodegradable plastic’s ability to break down within a year means it has several advantages over traditional plastics:

• It decreases the waste sent to landfills or incinerators. When you toss traditional plastic into the trash, it has a negative environmental impact because it can wind up in landfills, where it can potentially sit for hundreds of years, or incinerators, where it will be burned and release harmful chemicals into the natural environment. Conversely, biodegradable plastic has an environmental benefit: it will break down in a landfill and doesn’t need to be burned.
• It takes less energy to manufacture. The manufacture of biodegradable plastics often takes less energy than traditional plastics, meaning that it takes fewer fossil fuels and produces fewer greenhouse gas emissions that harm the planet.
• It releases fewer harmful substances when breaking down. While traditional plastics can leach toxic chemicals into the environment as they sit, well-made biodegradable plastics should break down with few harmful byproducts. Instead, biodegradable plastics release a combination of water, carbon dioxide, and biomass (which is often simply leftover plant materials).

While biodegradable may aid in the environment conflict against traditional plastics, it does have some drawbacks:

• It may not break down completely. While scientists have yet to determine the effects of biodegradable plastic, there is evidence that certain types do not break down completely. When biodegradable plastics only partially break down, it can be even more harmful to the environment than if it had stayed whole since the smaller pieces (called microplastics) become harder to clean up or identify.
• It can release harmful substances when breaking down. While biodegradable plastic releases fewer harmful chemicals when breaking down, that doesn’t mean it’s harm-free—certain types of biodegradable plastics can release harmful substances like metals and methane.
• It reinforces a single-use mindset. Biodegradable plastic reinforces the idea of single-use materials, encouraging excess waste production as a sustainable practice. This mindset can have negative consequences because consumers may turn to biodegradable plastics as the best solution for environmental issues, passing up more environmentally friendly practices such as low-waste living, recycling, prioritizing organic materials, and composting food waste. Learn more about recycling in our comprehensive beginner’s guide here.
• It’s expensive to produce. Biodegradable plastic is more expensive to produce than traditional plastic, making it challenging to encourage plastic manufacturers (without incentives) to switch to biodegradable plastic for their products and packaging.

While biodegradable plastics can, in theory, replace almost every use for conventional plastics, its higher cost prevents many manufacturers from making the switch. However, you still encounter biodegradable plastics daily—look for a label that describes the plastic as biodegradable. Biodegradable plastics are most commonly used to make things like:

1. 1. Food packaging: Manufacturers can make biodegradable food packaging out of a range of items, from cheese byproducts to almond shells. Common biodegradable plastic products include takeout containers, carry-out bags, and coffee cups.
2. 2. Disposable tableware: Biodegradable plastic plates, cups, and utensils are easy to find on the market—some have the texture of paper or cardboard while others feel smoother like traditional plastic.
3. 3. Plastic bags: There are many biodegradable plastic bags in circulation, including shopping bags, produce bags, and other single-use bags.
4. 4. Packing peanuts: While traditional packaging peanuts were made from non-biodegradable polystyrene, there are now many starch-based packaging peanuts available that are biodegradable.
5. 5. Plant pots: Many companies now package their plants in biodegradable containers, meaning the packaging can be planted straight into the ground and will decompose naturally in the soil.
6. 6. Medical products: Many medical materials like surgical sutures and wound dressings are made from biodegradable material, so they naturally break down without needing an invasive technique to remove the material after the patient has healed.

Get the MasterClass Annual Membership for exclusive access to video lessons taught by science luminaries, including Jane Goodall, Neil deGrasse Tyson, Chris Hadfield, and more.