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If you’ve never seen a banana tree, you might not realize just how impressive they can be.
They tower over you and can be 6 to 12 meters tall.
That entire plant grows and produces fruit within a single year.
That catch is it will only produce fruit once.
After this, the entire above-ground part of the plant dies,
and you need to cut the tree down to its underground stem and roots.
This lets the new shoots, called suckers,
grow and give you more bananas the following year.
This cycle can go on year after year,
which is good since most types of farmed bananas don’t produce seeds.
Now I kind of lied to you, because banana trees aren’t technically trees at all.
Their “trunk” isn’t made of wood. It’s called a
pseudostem because it’s just very tightly packed leaves.
You might see where this is going.
After you sell your delicious bananas,
you’re left with those massive stalks you need to cut down every year.
that’s a ton of plant waste.
Not everyone wants to eat green bananas the color,
but everyone would like to eat green bananas, the environmentally friendly kind.
Their carbon footprint isn’t huge compared to other foods,
but it would be nice to put all that waste to good use.
The world isn’t about to give up smoothies!
Bananas are the world’s largest fruit crop –
if you classify tomatoes as a vegetable,
so just have at it in the comments.
Just fight, and we’ll watch
Over 150 million tonnes of bananas and plantains are grown each year.
The catch is that 88% of a banana plant is inedible.
That means over 1.3 billion tons of banana waste every year.
That’s the weight of around 250 Great Pyramids of Giza!
But where there is a problem, there can also be an opportunity.
Many researchers think that all this waste could actually be ripe for a bunch of potential uses.
From plastics to energy and even skateboards,
many researchers have looked in how to turn
all this waste into something valuable.
Now, reusing parts of a banana plant isn’t a new idea.
Many cultures have long used the leaves
as food packaging and fibers for clothing and ropes.
And some folks eat additional parts, like the core of the pseudostem,
or the flowers before they turn into fruit.
Plant waste is often used as fertilizer or as food for livestock, which makes sense.
Except that the banana byproducts lack nutrition,
so they’re not ideal for that kind of thing.
So, much of that banana waste goes to, waste. It rots or is burned —
which can create environmental and air quality issues.
And that’s a big part of why repurposing it into something else is so exciting.
So, let’s start with the basics.
Banana stems are too flexible to build anything rigid on their own.
But they have a ton of fibrous material in them,
and we already use similar fiber
from cotton, sugar cane, corn and many other plants.
Just like wood, banana pseudostems can be converted into paper.
And it turns out it’s more water-resistant and stronger than paper made from wood pulp!
The fibers from banana pseudostems can also be mixed with plastic polymers
to strengthen them.
Researchers have built everything from furniture to skateboards out
of these banana fiber-strengthened materials.
One study found adding pseudostem fibers to epoxy resin
increased its impact strength by 40% and its tensile strength by 90%.
Another found that polyester resin skateboard decks reinforced
with 15% banana stems had excellent strength and flexibility.
Which might be important for skateboarders,
I would not know.
When you get right down to it, all that fiber is made of cellulose,
an organic compound that helps give plants their structure.
And we can find chemical uses for the cellulose as well.
Researchers have found that the amount of
cellulose in banana pseudostems makes them ideal for bioplastic.
To make traditional plastic, you start with fossil fuels as your raw material.
Instead, bioplastics use more sustainable sources like cellulose –
which generally grew, like, last year as opposed to a couple geologic eras ago.
This means we don’t need to rely on fossil fuels as much,
manufacturing the plastic tends to emit less carbon,
and the plastic tends to break down faster once you throw it away.
But growing plants specifically to make plastic can lead to other
environmental issues from fertilizer and pesticides. It would be perfect if there
were already a massive amount of plant waste lying around.
Researchers have found that you can make anything from
a rigid plastic tray to a flexible plastic bag from banana pseudostems.
And it would theoretically be recyclable up to 3 times –
at least, it was under laboratory conditions.
One job banana bioplastic is suited for is packaging other produce.
The science of packaging fruits for shipment is pretty complex.
You not only need to protect the fruit on its journey,
but you also need to control how quickly it ripens
so that it’s not past its prime when it hits shelves.
Take mangos as an example.
Like many fruits, they release a gas called ethylene,
which causes them to ripen.
So you need a package that allows this gas to escape.
How permeable a plastic film is to gases depends on things
like the plastic’s density and the characteristics of its molecules.
And it turns out cellulose film has a much higher gas permeability
than polyethylene, the most common fruit packaging material.
A 2021 study found packaging made from banana plants
delayed the ripening of mangos compared to standard polyethylene plastic.
And when composted,
it decomposed in just 4 weeks.
Much faster than the standard plastic packaging.
Believe it or not, this is just the start.
Carbon powder made from heated banana peels has antibacterial properties,
and similar powder could play a role
in making low-cost solar panels.
Fabric, food thickeners, biofuels, contaminant absorbers…
scientists have found tons of potential in banana plant waste.
But the catch is almost all of these are in the early research stage.
For example, some bioplastics researchers envision a future where banana farmers
could make extra money by grinding pseudostems
into powder and selling it to plastic makers.
But way more work is needed to set up a banana bioplastics supply chain.
Farmers and plastic makers would need to agree
on how that powder is made and transported to manufacturing facilities.
On the other end of things, customers and businesses
would need to make the switch to banana bioplastics.
It would be a tremendous amount of work to get everyone on the same page.
Despite this, everyone agrees that banana waste is a tremendous opportunity.
It shows how you can take waste being produced anyways
and turn it into something much more a-peeling.
Thanks for watching this SciShow video
and thank you to Brilliant for supporting it!
There were a lot of percentages in this episode,
from the 88% of the banana plant that’s inedible
to the 15% of your skateboard deck that could be reinforced with banana stems.
And if that kind of everyday use of percents lig hts your fire,
then you’ll enjoy the “Everyday Math” Brilliant course.
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by clicking the link in the description down below or going to Brilliant.org/SciShow.
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