This SciShow video is supported by Brilliant.  As a SciShow viewer, you can keep building your   STEM skills for 20% off an annual premium  subscription at Brilliant.org/SciShow. [ intro ] 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 mangoes 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 mangoes 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. Brilliant is an online learning  platform with courses in Science, computer science, and everyday math. Through interactive puzzles and lessons, they bring you into the world of STEM.

And in this course especially,  they bring STEM into the world. This course has no prerequisites  and can be a great way to reinforce your math foundations by putting percents, fractions, and  ratios into everyday contexts. You can check it out, along with  over 60 other Brilliant courses by clicking the link in the description down  below or going to Brilliant.org/SciShow.

As a SciShow viewer, you get 20%  off an annual premium subscription. With Brilliant, math doesn’t  have to make you go bananas! [ outro ]