Are you trying to achieve a sustainable lifestyle? Checking labels to make sure the product you are about to buy can be recycled? You rock! And when the product is labelled as biodegradable, you are assuming that it should be good for the planet, right?
But is it? What does "biodegradable" mean? At Notpla, we have gathered our technical and sustainability experts to demystify this misleading word.
How do we define Biodegradable?
Biodegradability at a glance
We define biodegradable as the ability for a material to be broken down naturally by the organisms in an ecosystem. Simply put, biodegradable means that the material naturally breaks down into smaller components, such as sugars and gases.
The biodegradation occurs thanks to microorganisms, such as bacteria and fungi. However, just because a product says it's biodegradable doesn't mean it degrades everywhere. Indeed, materials need specific conditions to biodegrade.
Now let's get a bit more technical!
The process of biodegradation is the breakdown of organic matter by microorganisms, such as bacteria. Organic matter is a carbon-based compound found within the environment. The result of biodegradation is water, carbon dioxide, and biomass (such as sugars).
This biodegradation is a key part of any life cycle on our planet. When organic matter is processed by microorganisms, it releases carbon in the form of carbon dioxide. We know this may trigger alarm bells, as this process is increasing levels of carbon dioxide in our atmosphere. But above all, it is essential to all life on Earth.
How long does it take for things to biodegrade?
The confusion that surrounds the term "biodegradable" is that it does not reference any time scale. Thus something could take more than a lifetime to decompose.
Let's take wood, for example. As a sheet of paper, wood is easily biodegradable. Yet, as a building material, it can take tens or hundreds of years to decompose. We could also take the case of an insect. Although biodegradable in most contexts, if it finds itself trapped in amber it could remain intact for millions of years.
Thus, when designing material, it is key to consider the conditions necessary for biodegradation to occur. And as consumers, it is important to know how to best dispose of them.
What are the optimal conditions for biodegradation?
The best conditions for biodegradation are an optimal combination of temperature, water, oxygen and bacteria.
For example, an orange can have a relatively long shelf-life in a fridge, with controlled conditions. However, whenever it is removed to an environment with the necessary conditions for biodegradation, it begins to break down.
Just think of your orange forgotten at the bottom of your fruit bowl! The orange is taken from an environment with low light and temperature, into an environment where both of these are higher. This increases the speed at which microbes will break down the orange, resulting in faster biodegradation.
Our wormery has the best conditions for biodegradation. We tested five materials on their compostability. After 28 days, only the Notpla material, and the orange peel had been eaten by the worms. Just check by yourself with this video!
Why choosing materials suitable for their use matters
Problems can occur when materials end up in environments where they would biodegrade very slowly or can't biodegrade. Plastic is a material that can face this issue. Don't get us wrong, plastic has its uses, in fact there are many applications where slow biodegradation is a must.
For example, polyvinyl chloride (PVC) is resistant to biodegradation, making it a perfect material for sewage systems.
But just as materials that biodegrade quickly would not be suitable as pipes for drainage systems, perhaps there are applications where plastics are not the most suitable, for instance, packaging a sandwich?
Obviously, we wouldn't want our drainage systems to biodegrade. However, in some cases, it would be suitable for packaging to break down in a way that plastic doesn't. Take sandwich bags or plastic bottles, for example - we don't need these single-use plastics to stick around.
Polylactic acid (PLA) is often used as packaging by companies as a biodegradable alternative to fossil-fuel-derived plastics. There are lots of benefits to PLA, in particular, that it is made from plants, giving it a low carbon footprint. Yet, PLA requires a temperature of 58 °C to begin to break down. Biodegradation will not occur if this temperature is not reached. Therefore, PLA can only be disposed of in an industrial composting facility, of which there are few in the UK.
What is the difference between biodegradable and compostable?
Although often used interchangeably, biodegradable and compostable are different terms. The main difference being that biodegradation is a naturally occurring process, and compostability is human-driven biodegradation. Can't wait to master the term "compostability"? Don't worry, we will explore this second term next time.
As innovators, we are challenging ourselves to be a force for good.
At Notpla, we believe that single-use packaging should last no longer (well, maybe slightly longer) than the contents inside. While the food or drink you are buying will biodegrade in several weeks, plastic sachets or bottles can take more than 450 years. That's why we create materials just like a fruit peel, making packaging that disappears a few weeks after use.
Would you like to better understand the complex terminology surrounding sustainability? Have a look at our Notpla Glossary where we unravel the meaning of various terms related to sustainability!
This article was written with the support of Danny and Kendra
Danny Pitt, Technical Lead at Notpla
Danny has a background in chemistry and materials science, having gained his chemistry degree from Newcastle University in 2016. Having worked previously for other materials-focused start-ups, Danny has been with Notpla for nearly 2 years, leading the development and industrialisation of our thin films projects.
Kendra Quinn, Impact Associate at Notpla
With a background in sustainability and development, Kendra is developing Notpla's impact policy, researching legislation and sustainability of our new materials and processes. She is ensuring the company is on track towards its regenerative targets.