Bioplastics: How Bioplastics Work

Bioplastic products are plastic materials made from renewable biomass energy sources, such as corn and sugarcane. Bioplastics can also be biodegradable, meaning microorganisms can completely break them down into water and carbon dioxide. Bioplastics have become an increasingly popular form of plastic, used today for everything from cups and food production packaging materials to bottles and cutlery. The bioplastic market has exploded in popularity because of its green benefits. Many cities are banning single-use plastic, looking to transition from traditional plastics to biodegradable plastics.

Consider the following differences between bioplastics and traditional plastics:

• Environmental impact: All plastics are degradable; the difference with bioplastics is they are biodegradable, meaning they can be completely broken down into water, carbon dioxide, and compost by microorganisms, leading to fewer environmental issues. Petroleum-based plastics—such as food packaging, plastic bags, toys, and more—clog up landfills, taking more time to decompose and leading to worsened climate change.
• Material: Bioplastics are made from renewable energy sources. The creation of conventional plastics relies on non-renewable sources, such as petrochemical polymers.
• Production: The production of conventional plastics emits more greenhouse gases than bioplastics. In the sustainability movement, bio-based plastics are a step forward in releasing less methane and decreasing plastic waste. Bioplastics, a more eco-friendly type of plastic, have a smaller carbon footprint and are less likely to contaminate water supplies or lead to plastic pollution.

Bioplastics are made from renewable biomass sources, such as cornstarch, sugar cane, vegetable fats and oils, sawdust, wood chips, straw, and other raw materials. Bioplastic production involves processing, fermenting, and synthesizing natural biopolymers from starch and cellulose. Then the materials go through a forming process via injection molding to take shape. After use, bioplastics can decompose via UV light, oxygen, and heat over a few months.

There are two main types of bioplastic: PLA and PHA.

• Polylactic acid (PLA): PLA bioplastics are made from the sugar in cornstarch and sugar cane. These biodegradable and edible plastics are made by mixing corn kernels with sulfur dioxide and hot water. The kernels break down into starch, fiber, and protein, which then combine with citric acid to form a long-chain polymer that forms the building blocks for plastic.
• Polyhydroxyalkanoate (PHA): PHA bioplastics are made from bio-feedstock and microorganisms. Its microbes are deprived of nutrients but contain high levels of carbon, which produce carbon reserves to store in granules until they have enough to reproduce. PHA bioplastics are biodegradable and do not harm living tissue; thus, they are often used in creating medical equipment, such as slings and bone plates.

Many bioplastics are biodegradable and compostable plastics. At industrial composting sites, microorganisms break plastic products down into water, carbon dioxide, and compost for fertilizers within weeks and months. Some bioplastics, however, are non-biodegradable or “durable,” meaning they cannot be broken down easily at composting facilities.

Some communities do not have transparent systems for composting, which can lead to bioplastics being thrown out with regular trash and releasing more methane in a garbage dump. Some bioplastics also feature additives, so correctly handling and disposing of these plastics must be carefully monitored. Additionally, pesticides may be used to expedite the production of some bioplastics, which can harm the environment.

Get the MasterClass Annual Membership for exclusive access to video lessons taught by science luminaries, including Bill Nye, Terence Tao, Neil deGrasse Tyson, Chris Hadfield, Jane Goodall, and more.