What Biodegradable Plastic Is Made Of? Let’s Break It Down

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You might be surprised to know that the first plastic actually came from plants, not oil. Back in 1862, a British chemist named Alexander Parkes created something called Parkesine. It was made from cellulose (a natural material found in plants), so technically, it was the first bioplastic.

But the real explosion of plastic use didn’t start until 1907, when Leo Baekeland invented Bakelite – the first fully synthetic plastic made from fossil fuels. That’s what kicked off the modern plastic industry and led to the billions of plastic products we use today.

Interestingly, bioplastics didn’t disappear. In 1926, a French scientist named Maurice Lemoigne discovered PHB, a biodegradable plastic made by bacteria. Still, it wasn’t until much later—when people started realizing how much waste plastic was creating—that bioplastics got serious attention again. So in short:

• Bioplastics came first, but weren’t widely used.
• Synthetic plastic took over in the 1900s.
• Now, bioplastics are trying to make a comeback to help solve the problems regular plastic creates.

You can learn more about the history of bioplastics here. 

What is biodegradable plastic made of?

Biodegradable plastics are made from various raw materials and fall into several types. Despite the label, not all are plant-based or even naturally degradable in everyday environments.

That is why biodegradable plastics often have a shorter lifespan in the environment –they can be decomposed into water, carbon dioxide, or methane, and biomass by living organisms, such as microbes.

Common sources:

• Bio-based materials like corn starch, cassava, or cellulose
• Biodegradable synthetic polyesters, often fossil fuel-derived
• Plant-based oils such as sugarcane — which may or may not be biodegradable

Additives are often included to accelerate breakdown in the presence of light, oxygen, moisture, and heat. They typically degrade faster due to the action of microorganisms such as bacteria, fungi, and algae.

How do they break down?

Biodegradable plastics can decompose into water, carbon dioxide (or methane), and biomass through microbial action — but only under the right conditions.

Three main types of biodegradable plastics

Type	Source	Biodegradable?
Bio-based, not biodegradable	e.g. sugarcane	❌
Fossil-based, biodegradable	e.g. synthetic polyesters	✅
Bio-based and biodegradable	e.g. corn starch, cassava	✅

👉 Many “biodegradable” plastics are still made using petrochemicals (refined petroleum) – they’re just engineered to break down faster under industrial conditions.

The problems with biodegradable plastics

Despite their name, biodegradable plastics come with several challenges:

1. Microplastics

As they degrade, many break down into microplastics, which can be just as harmful to wildlife, marine ecosystems, and human health.

2. Environmental conditions matter

Biodegradable plastics require specific environments to break down, like industrial composting facilities with controlled heat and humidity. If they end up in a landfill or the ocean, decomposition can be severely delayed or may not happen at all.

Plus, biodegradable plastics don’t always break down into harmless substances; they can leave behind toxic materials.

3. Resource-intensive

Producing biodegradable plastics often demands significant water, land, and energy. Many are made from crops like corn or cassava, raising concerns over land use and food security.

4. Lack of waste management infrastructure

Most municipal waste systems aren’t equipped to process biodegradable plastics. Mixing them with traditional plastics can contaminate recycling streams and lower the quality of recycled material.

5. Greenwashing & misleading labels

Without clear labeling or guidance on disposal, claims like “biodegradable” can mislead consumers. Some bioplastics aren’t biodegradable at all – or they require special conditions rarely met in real-world settings.

6. Still single-use

Many biodegradable items are still disposable products, like cups, bags, and packaging, that continue to support a throwaway culture.

7. No specifications

The label “biodegradable” often comes without any disposal instructions or scientific clarity. This creates confusion. The term “bio” might refer to:

• Bio-sourced — made from biological, renewable resources
• Biodegradable — capable of breaking down through microbial action

But not all bio-sourced plastics are biodegradable. And not all biodegradable plastics are bio-based – some come from petrochemicals.

This lack of standardization and transparency makes it hard for consumers to make responsible choices and increases the risk of improper disposal.

Pros & cons of biodegradable plastics

Pros:

• Can break down (under specific conditions) via microbial activity
• May use renewable resources instead of fossil fuels
• Potential to reduce landfill waste if properly managed

Cons:

• May still use non-renewable resources or harmful additives
• Often don’t decompose in home environments or regular landfills
• More expensive to produce due to material density and processing
• “Biodegradable” ≠ compostable or recyclable

How are biodegradable plastics made?

The most familiar bioplastics are made from natural materials such as corn starch. So, let’s see what the manufacturing process of plastic from statch looks like:

1. Preparation: Cassava tubers are peeled, washed, and grated.
2. Filtering: Grated cassava is mixed with water and filtered to extract starch.
3. Settling: Starch is allowed to settle, then washed and re-settled for purification.
4. Drying: Starch is oven-dried at 105ºC for 4 hours to remove moisture.
5. Moisture testing: The dried starch is tested for remaining moisture using infrared tools.
6. Mixture preparation: 1kg cassava starch + 2kg polyvinyl alcohol + 100g talc + 100g urea + 400ml glycerin.
7. Extrusion: This mixture is processed using a blown-film extruder to create biodegradable film.

Source: The Production of Bioplastics from Starch

FAQs

Are biodegradable plastic bags better?

They may be better than conventional plastic bags if disposed of properly. But in most cases, reusable alternatives are far more sustainable.

Can biodegradable plastics still harm the environment?

Yes. Without the right disposal environment, they can persist and even pollute. Some may also release methane (a potent greenhouse gas) during anaerobic degradation in landfills.

How long do they take to decompose?

There’s no single answer. In industrial composting settings, it could be under 6 months. In landfills or the ocean? Potentially decades. And some don’t fully decompose at all.

Final thoughts

While the idea of biodegradable plastics is appealing, the reality is far more complex.

The term “biodegradable” has been widely used—and misused—without clear standards. Many biodegradable plastics won’t break down unless disposed of in ideal conditions that are rarely available.

🌱 Better choice? Avoid single-use plastics altogether – biodegradable or not. If you must choose disposables, look for home-compostable certifications and clear disposal instructions.