Plant-based plastics

More than eighteen trillion pounds of plastic have been produced to date, and eighteen billion pounds of plastic flows into the ocean every year. It ensnares the marine animals we cherish and the fish we put on our plates, it appears in the table salt we use, and it’s even found in our own bodies.

As more research on the impact of using so much plastic comes to light, consumers and manufacturers are left scrambling for an alternative to the ubiquitous material, and bioplastics have emerged as a potential alternative.

At a glance, the name sounds promising, with a prefix that hints at an Earth-friendly product. But is bioplastic the panacea for our environmental woes? An easy-to-use single-use item that feels like plastic minus the guilt?

The answer?

It’s complicated, say scientists, manufacturers, and environmental experts, who warn its potential merits rest on many “ifs.”

Bioplastic simply refers to plastic made from plant or other biological material instead of petroleum. It is also often called bio-based plastic.

It can either be made by extracting sugar from plants like corn and sugarcane to convert into polylactic acids (PLAs), or it can be made from polyhydroxyalkanoates (PHAs) engineered from microorganisms. PLA plastic is commonly used in food packaging, while PHA is often used in medical devices like sutures and cardiovascular patches.

Because PLA often comes from the same large industrial facilities making products like ethanol, it’s the cheapest source of bioplastic. It’s the most common type and is also used in plastic bottles, utensils, and textiles.

About eight percent of the world’s oil is used to make plastic, and proponents of bioplastic often tout a reduction in this use as a major benefit. This argument rests on the idea that if a plastic item does release carbon once it’s discarded, as it degrades, bioplastics will add less carbon to the atmosphere because they’re simply returning the carbon the plants sucked up while growing (instead of releasing carbon that had previously been trapped underground in the form of oil). Whether bio-based plastics are ultimately better for the environment than oil-derived ones “is a big question based on many ‘ifs,’” she says. In other words, there’s no clear answer at present. Industrial composting is necessary to heat the bioplastic to a high enough temperature that allows microbes to break it down.

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