Biodegradable Plastics

Plastics have provided considerable packaging convenience for many things. And they’re inexpensive, which makes them disposable.  However, our enormous oceans now have seas of plastic in them that, among other problems, is killing sea life.

Some plastics are recyclable, and companies such as Trex are collecting the kind of plastics used by grocery stores or newspapers and producing boards that are used for outdoor flooring or park benches. However, if we can maintain the usefulness of plastics without their polluting nature, we would then have a great contribution toward living with Earth in a sustainable way.  I’ll add comments afterwards.

•      •      •      •     •      •      •      •

Scientists Develop Truly

Biodegradable Plastics

Olivia Rosane

EcoWatch

SCIENCE

Apr. 23, 2021

 

A research team at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC), Berkeley has found a way to make biodegradable plastics actually disappear.

While biodegradable plastics have been touted as a solution to plastic pollution, in practice they don’t work as advertised. Ting Xu, study coauthor and UC Berkeley polymer scientist, told Science News:

 

“Biodegradability does not

equal compostability.”

 

But by studying nature, Xu and her team have developed a process that actually breaks down biodegradable plastics with just heat and water in a period of weeks. The results, published in Nature on Wednesday, could be game-changing for the plastic pollution problem. Xu told Science News:

 

“We want this to be in every grocery store.”

 

 

What’s the Problem?

Humans have tossed 6.3 billion metric tons of plastic since the 1950s and only recycled 600 million metric tons, leaving 4.9 billion metric tons sitting in landfills or otherwise polluting the environment, BBC Future reported. Plastic waste is a problem because it does not disintegrate, but only breaks apart into tinier pieces known as microplastics, which have  infiltrated  almost every part of the planet — and our bodies.

Biodegradable plastics were supposed to solve this problem, but face three main limitations, according to Berkeley News and Berkeley Lab.

  1. They get missorted and contaminate recyclable plastics.
  2. They end up in landfills, where the conditions are not suitable for plastic breakdown, so they last as long as forever plastics.
  3. When they are composted, they don’t entirely degrade and still leave microplastics in the soil.

 

Xu told Science News that she had found supposedly biodegradable plastics in compost. Xu said:

 

“It’s worse than if you don’t

degrade them in the first place.”

 

 

The Solution

To create plastics that do disappear, Xu and her team studied nature.

 

“In the wild, enzymes are what

nature uses to break things down

— and even when we die, enzymes

cause our bodies to decompose naturally.”

 

Xu told Berkeley Lab:

 

“So for this study, we asked ourselves,

‘How can enzymes biodegrade

plastic so it’s part of nature?’”

 

The researchers focused on a polyester called polylactic acid, or PLA, which is used for most compostable plastics. Berkeley News explains how the process works:

The new process involves embedding polyester-eating enzymes in the plastic as it’s made. These enzymes are protected by a simple polymer wrapping that prevents the enzyme from untangling and becoming useless. When exposed to heat and water, the enzyme shrugs off its polymer shroud and starts chomping the plastic polymer into its building blocks — in the case of PLA, reducing it to lactic acid, which can feed the soil microbes in compost. The polymer wrapping also degrades.

The researchers found that as much as 98 percent of their modified plastics converted into small molecules, leaving no microplastics behind. At room temperature, the plastics degraded by 80 percent after about a week. In the high heat of industrial composting conditions, plastics degraded even faster. They also disappeared after a few days in warm tap water.

 

 

What’s Next?

Aaron Hall, another study coauthor and a former UC Berkeley doctoral student, has founded a company to commercially develop these plastics.

Xu also thinks the process could apply to different types of polyester plastic and various recycling problems, such as developing compostable glue for electronics. Xu told Berkeley News:

 

“It is good for millennials to think about

this and start a conversation that will

change the way we interface with Earth.

 

“Look at all the wasted stuff we throw away:

clothing, shoes, electronics like cellphones

and computers. We are taking things from

the earth at a faster rate than we can return

them. Don’t go back to Earth to mine for

these materials, but mine whatever you

have, and then convert it to something else.”

 

•      •      •      •     •      •      •      •

As I often do, I like to add D’s perspective to an issue or development.

 

“Too often, humans throw away items that are still usable. Think about Thrift Shops as an alternative to trash. Think about using an item longer, even if it’s not pristine. 

“We have said in the past to try to not use much plastic. Use glass containers. Use reusable bags. And yet, it is close to impossible to not use any plastic. 

We herald the scientists who are working toward the breakdown of plastics and cannot wait until they are available to all of us. 

“Until then, be mindful of what you use and how you dispose of it.”

 

 

 

Leave a Reply

Your email address will not be published. Required fields are marked *

* Copy This Password *

* Type Or Paste Password Here *