The smallest solution to one of our biggest problems - Tierney Thys & Christian Sardet

Summary

This video script explores the global plastic pollution crisis and the challenge of biodegrading plastics. It explains how most plastics, due to their complex molecular structure, resist degradation by natural microbes, leading to vast amounts of waste. Despite advancements in discovering and engineering microbes and enzymes capable of breaking down certain plastics like PET, much of the plastic waste remains resistant to biodegradation. The script highlights efforts to find heat-tolerant microbes, the potential of bioengineering, and the need for more sustainable plastic alternatives to reduce environmental harm.

Takeaways

• 😀 Microbes are constantly breaking down organic materials, but plastics are a major exception due to their resilience.
• 😀 Plastics, made from oil, gas, and coal, are polymers that are difficult to biodegrade due to their strong chemical bonds and synthetic nature.
• 😀 Most plastics, like Polyethylene, Polypropylene, and PET, have been piling up for decades and do not break down biologically.
• 😀 Only 10% of plastic waste is recycled, while 60% is incinerated or sent to landfills, and 30% leaks into the environment, contributing to pollution.
• 😀 An estimated 10 million tons of plastic waste enter the ocean each year, polluting ecosystems and the food chain.
• 😀 In 2016, researchers discovered a bacterium, Ideonella sakaiensis, that can break down PET plastic using enzymes that work at low temperatures.
• 😀 Scientists have enhanced these plastic-degrading enzymes, speeding up the process of breaking down PET by up to six times.
• 😀 While PET plastic degradation shows promise, other plastics like Polyethylene and Polypropylene remain challenging to break down due to their higher temperature requirements.
• 😀 Researchers are exploring microbial enzymes from extreme environments, such as compost piles, to tackle tougher plastics that require higher temperatures to degrade.
• 😀 Despite advancements in bioremediation, reducing plastic production and designing environmentally friendly polymers remains crucial for solving the plastic waste crisis.

Q & A

What is the main challenge with biodegrading plastics?

The main challenge with biodegrading plastics is that most plastics, such as polyethylene, polypropylene, and polyester-terephthalate (PET), cannot be easily broken down by microbes because they are made of long, synthetic polymer chains that microbes haven't evolved the enzymes to digest.

Why are plastics difficult for microbes to break down?

Plastics are difficult for microbes to break down because they are made from synthetic polymers created through high-temperature processes and require high heat to break their chemical bonds. This makes them resistant to degradation, as such temperatures are lethal to most microbes.

How are plastics typically produced?

Plastics are typically produced by refining molecules from oil, gas, and coal and converting them into long polymer chains through a process that requires high temperatures, high pressure, and various chemical modifications.

How much plastic does humanity produce each year, and what happens to it?

Humanity produces roughly 400 million tons of plastic each year. Of this, 80% is discarded as trash, 60% is incinerated or goes into landfills, and only 10% is recycled. Additionally, 30% of plastic waste leaks into the environment, contributing to pollution.

What is the fate of plastic in the ocean?

An estimated 10 million tons of plastic waste end up in the ocean each year, mostly in the form of microplastic fragments. These microplastics pollute the food chain and have long-term environmental impacts.

What significant discovery was made by Japanese researchers in 2016?

In 2016, Japanese researchers discovered a bacterium called Ideonella sakaiensis 201-F6, which contains enzymes capable of slowly breaking down PET plastic at relatively low temperatures.

How were plastic-digesting enzymes improved in the lab?

The genes coding for the plastic-digesting enzymes from Ideonella sakaiensis were isolated, and bioengineers combined and enhanced these enzymes, creating super-enzymes capable of breaking down PET up to six times faster.

What is the limitation of the lab-grown PET-digesting enzymes?

Although the lab-grown enzymes break down PET faster, they still take weeks to degrade a thin film of PET and work best at temperatures below 40˚C, limiting their effectiveness in environments with higher temperatures.

How have other researchers tackled the temperature challenge in plastic degradation?

Researchers in Japan discovered powerful degrading enzymes called Leaf Branch Compost Cutinases in compost piles, which work in warmer environments. These enzymes can degrade PET at temperatures up to 70˚C, which weakens the plastic and makes it easier to digest.

What is the current state of biodegradation for plastics other than PET?

Currently, there are no known microbes or enzymes that can effectively degrade other common plastics like polyethylene (PE) and polypropylene (PP), which require even higher temperatures to break down. Therefore, most of these plastics are processed through energy-intensive methods, such as incineration or chemical treatments.

What steps are being taken to address the plastic waste problem?

Scientists are searching for heat-tolerant plastic-eating microbes in extreme environments and engineering better enzymes to tackle the issue. However, these solutions are not enough by themselves, and there is an urgent need to rethink our relationship with plastics, design more biodegradable polymers, and reduce plastic production.