字幕表 動画を再生する 英語字幕をプリント PLASTIC IS EVERYWHERE. FROM THE CAMERA RECORDING ME RIGHT NOW, TO THE DEVICE YOU'RE WATCHING THIS ON, THE CLOTHES THAT WE'RE WEARING… THE GALLON OF MILK YOU DRANK STRAIGHT OUT OF THIS MORNING, AND THE FRIDGE THAT YOU POPPED IT BACK INTO... WHICH IS GROSS, BY THE WAY. BUT THAT'S BECAUSE IT'S A PRETTY AWESOME INVENTION. PLASTIC IS FLEXIBLE, DURABLE, TUNABLE, AND IT'S CHEAP. BUT FOR ALL OF PLASTIC'S SUPERPOWERS, IT AS AN OBVIOUS DARK SIDE. IT HAS A MASSIVE CARBON FOOTPRINT, WREAKS HAVOC ON OUR NATURAL ECOSYSTEMS, AND IS SO PERVASIVE THAT IT'S LITERALLY SHOWING UP IN THE FOOD WE EAT AND AIR THAT WE BREATHE. SOME WOULD ARGUE THAT WE JUST NEED TO QUIT PLASTIC COLD TURKEY. BUT BECAUSE WE'RE SO WRAPPED UP IN IT, THAT MIGHT BE EASIER SAID THAN DONE. BUT WHAT IF WE COULD UPGRADE TO SOMETHING BETTER? HOW CLOSE ARE WE TO REINVENTING PLASTIC? THE LIFE CYCLE OF MOST PLASTICS STARTS WITH PETROCHEMICALS, WHICH ARE USED TO FORM SOME KIND OF SOURCE MATERIAL, LIKE THESE PELLETS CALLED…. I KID YOU NOT… 'NURDLES.' - So you can have these plastic pellets that get melted into something like plastic packaging for instance, or maybe it gets blow molded into a water bottle... that bottle might go somewhere else, where a label gets put on top of it, where it goes somewhere else, where it gets filled. - Plastics are polymers. "Poly" means many, and "mers" means parts. So, basically small molecules which are chained together to make a really large molecule, or a macromolecule. Some of these macromolecules can be shaped using heat and pressure And that's what plastics are. So you can start with ethylene gas, you polymerize into polyethylene, which is a plastic. And you can use it in various shapes and forms. POLYETHYLENE IS JUST ONE OF COUNTLESS TYPES OF PLASTICS WITH DIFFERENT PROPERTIES, EACH PERFECTLY SUITED FOR THEIR APPLICATION, FROM SEALING A HOUSE, TO LINING A CAR SHIPPING A PRODUCT, WRAPPING PRODUCE, KEEPING YOUR SODA CARBONATED OR YOUR CLOTHING FROM CRUMBLING INTO A MILLION PIECES WHEN YOU SWEAT. (WHICH IS A DIFFERENT TYPE OF VIDEO). Packaging is the largest consumer of polymers, or plastics. We are interacting with them every day. AND THAT'S ONE MAJOR CHALLENGE OF RE-INVENTING PLASTIC. IT'S FINDING A REPLACEMENT THAT CAN DO ALL THESE THINGS. A MIRACLE MATERIAL WHICH POSSESSES ALL THE INCREDIBLE PROPERTIES OF PLASTIC, BUT IS STILL SUSTAINABLE TO PRODUCE, USE, AND DISPOSE OF, MEANING IT'S BOTH BIO-BASED AND BIODEGRADABLE. - Bio-based is, where does the carbon in the material come from? Is it rapidly renewable? So, if it's rapidly renewable, bio-based carbon, is it from plants? Is it from waste bio-gas? Biodegradable is what happens to a material at end of life. Can it be prone to enzymatic attack by microorganisms, by bacteria, by fungi? Can they break it down and convert it into something else? - PLA is polylactic acid. It's one of the plastics which is bio-derived, biodegradable, and compostable. RIGHT NOW, PLA IS THE MOST WIDELY AVAILABLE “BIOPOLYMER” ON THE MARKET. AND YOU MIGHT ALREADY BE FAMILIAR WITH IT… FOR BETTER OR WORSE. - People always say, "Oh, I know what you're talking about! I used it in my straw in my coffee yesterday and it turned to a wet noodle." But one of the other bigger challenges is PLA generally will only break down in industrially compostable environments. It needs high heat and high pressure. INDUSTRIAL COMPOSTING IS A CHALLENGE FOR THE SAME REASON THAT RECYCLING IS: IT'S EXPENSIVE, BUT NOT PROFITABLE RIGHT AWAY; IT REQUIRES MASSIVE INFRASTRUCTURE TO BE BUILT FROM THE GROUND UP; AND IT DOESN'T CATCH ANYTHING THAT DOESN'T JUST WALTZ THROUGH ITS DOOR. SO, IF YOU THROW A RECYCLABLE SODA BOTTLE IN THE WRONG BIN OR A 'COMPOSTABLE' PLA CUP IN YOUR BACKYARD, THE PLASTIC IS STILL STUCK. IT'S NOT GOING TO GET BROKEN DOWN. THAT'S WHY MOLLY AND HER TEAM AT MANGO MATERIALS ARE FOCUSED ON A DIFFERENT KIND OF BIOPOLYMER. ONE THAT DEGRADES NATURALLY, BUT ONLY WHEN YOU WANT IT TO... AND ROLLS OFF THE TONGUE: POLYHYDROXYALKANOATES. - Polyhydroxyalkanoates are a family of naturally occuring biopolyesters. It's the way bacteria have evolved over billions of years to store carbon in case of famines coming. PHAs were identified in bacteria over a hundred years ago. The challenge has been how to commercialize them. TYPICALLY, USING BACTERIA TO PRODUCE PHA IN THEIR CELL WALLS REQUIRED FEEDING THEM SOMETHING LIKE SUGAR OR VEGETABLE OILS. BUT BECAUSE THOSE ARE AGRICULTURAL PRODUCTS, THE PROCESS CAN BE DIFFICULT AT BIG SCALES. BUT OVER A DECADE AGO, MOLLY AND HER RESEARCH TEAM AT STANFORD STARTED TO TOSS AROUND ANOTHER IDEA… ONE THAT HAS SINCE BECOME REVOLUTIONARY. What if instead, we used methane? There's naturally occurring methanotrophs, or bacteria that can consume methane, and could they produce PHA? It would make sense that they could because this is an ancient carbon storage mechanism in organisms. I'd say that was the Eureka moment if there was one, and now there's just been continual sort of successes as we validate, can you use waste methane? What kind of properties can you get from compounding or formulating the polymer correctly? How do you scale up? AND THAT'S BEEN THE MAJOR CHALLENGE FOR ANY KIND OF NEXT-GENERATION MATERIAL TO BE ABLE TO COMPETE WITH PETROLEUM-BASED PLASTIC PRODUCTS. - If you go to a dollar store, you see items which are about $1. So the product by itself has to be less than $1, along with the package. So the package has to be relatively very, very cheap in order to succeed in the market. TO DRIVE A COMPETING MATERIAL'S COSTS DOWN THAT FAR, IT WOULD HAVE TO BE SO EASY TO PRODUCE THAT IT WOULD BE LIKE PULLING IT OUT OF THIN AIR. AND ACCORDING TO MANGO, THAT THIN AIR IS THE DELICIOUS SMELL OF METHANE, WAFTING FROM THE LANDFILLS AND WASTEWATER TREATMENT PLANTS RIGHT IN OUR BACKYARD. - We're able to pipe right off of the existing infrastructure that they have here. The tank that you see behind me here is called an anaerobic digester. And that is where there's organisms called methanogens that live there and eat the waste, and actually produce methane, hence the name "methanogen." Behind me, we have the fermentor where the bacteria live, grow, and make the biopolymer. It actually happens in two stages. So the first, we call reproduction, where we actually want the organisms to double, and then, we actually want all of those millions of organisms to transform, which means to take that carbon and build up the biopolymer, polyhydroxyalkanoate, inside of cell walls, Once they are fat and happy, we basically have to pull the polymer out of their cell walls through the harvesting step. We remove the cell mass, as we don't need that part - we really want the powder, which is actually in step six where we've removed the water, and you're left with the powder. But in order for it to be turned into various products, it needs to generally be in pellet form, which is step seven. - If we want to look at what the utopian future could be, in my book, it would be anaerobic digestion to materials, to fuels, to energy. So, we could take these local, decentralized, already-existing facilities - they're already collecting some form of waste. They can anaerobically digest it to methane. Then we are dealing with our waste onsite. And not only that, we are creating a more resilient economy, because we can actually use this material, that's seen as a waste, as a feedstock to the everyday materials and products we need. FOR MOLLY AND HER TEAM TODAY, THOSE PRODUCTS ARE FIBERS FOR TEXTILES, SMALL PACKAGING ITEMS, AND EVEN 3D-PRINTED TOOLS FOR USE IN SPACE. BUT BY SLOWLY BUILDING DEMAND AND IMPROVING THEIR PRODUCTION PROCESS, THEY BELIEVE THAT SOON THEY'LL BE ABLE TO WORK WITH SOMETHING LIKE PLASTIC BAGS. One of the amazing things about PHAs is they can be tailored for lots of different applications. So you can get different properties, whether it's mechanical properties, processing, or even end-of-life biodegradability properties. PHAs can also biodegrade in your backyard compost, so home compost, or even environments where no oxygen is present. It could give producers and other people in the value and supply chain reassurance that it won't be polluting indefinitely for hundreds or thousands of years. SO IF ALL WE NEED TO DO IS MENTOR SOME METHANE-MUNCHING MICROBES TO PRODUCE PHA AT SCALE USING WASTE FACILITIES ALL OVER THE WORLD, GRADUALLY BUILD THE CAPACITY WE NEED TO COMPETE WITH PETROCHEMICAL PLASTICS, AND SIT BACK AND WATCH AS OUR LANDFILLS BECOME GOLD MINES, HOW CLOSE ARE WE TO RE-INVENTING PLASTIC? - We are having a technological leap forward. So the technology of the next generation of plastics is already here; and it's the infrastructure that we have to develop around it. Whether it's bioplastics, compostable plastics, or whether it is processing once the infrastructure is in place, we'll have the next generation of plastics taking over. - So, we're very close to replacing petroleum and polluting plastics. These materials are already here. If everything just fell into place, we'd be looking at single digit years to get there. There's a sweet spot between technology and economics. Packaging and plastics play a very important role in the success of the supply chain. Sustainable plastics, they are going to grow from here on - there's no doubt about that. So once the cost of the production, the infrastructure lines up I see a very bright future for the bioplastics out there. Methane might stink, but our YouTube channel sure doesn't. Make sure to subscribe for all your science news check out our website at Seeker.com, our Instagram, @Seeker, our Facebook, /SeekerMedia, and, for more about plastic, check out this episode of Elements where we cover a team trying to pull it all out of the Pacific Ocean. It's a lot of work. Anyway, thanks for watching! See ya next time!