At a time when the planet is increasingly troubled by the persistent negative impact on the environment of plastics made by petrochemical plants, companies are investing billions of dollars to accelerate the production of plastics from natural and renewable products that will be safe to compost or will degrade in the environment if the conditions are right.
Bioplastics have long been used in the medical sector. Dissolving stitches, for example, are often made of a bioplastic thread that dissolves harmlessly in the body.
But the nascent bioplastics industry is eyeing a much bigger role for materials extracted from corn, sugar, vegetable oils and other renewable substances, in hopes of appropriating an ever-larger portion of a market worth US$600 billion globally.
Since their large-scale production began in the 1950s, plastics derived from fossil fuels have made foods safer to eat and vehicles safer to drive, for example. Yet plastics are considered one of the biggest environmental threats on the planet and their production generates millions of tons of greenhouse gases each year.
Of the nine billion tonnes of fossil fuel plastics produced since the 1950s, only 9% have been recycled, studies show. The rest has been buried in landfills or incinerated, or pollutes land and waterways. The chemical structure of plastics derived from fossil fuels means that they can never fully decompose and instead break down into smaller and smaller particles.
Currently, bioplastics represent only 1% of global plastic production.
Businesses and investors see it as a great opportunity. Data from i3 Connect reveals that investment in bioplastics manufacturing reached US$500 million in the first three months of 2022, compared to US$350 million in the last quarter of 2021. The money comes from both companies than venture capitalists.
Zion Market Research calculates that the bioplastics market will grow from US$10.5 billion in 2021 to just under US$30 billion in 2028.
There are currently two major types of bioplastic, PHA and PLA.
PHA can be produced with microorganisms that ferment in canola oil. This results in plastic balls that can be molded to produce the usual objects. PHA could biodegrade in six months in a marine environment and two years underground.
PLA is usually made from the fermentation of sugar that comes from corn and sugar cane. Unlike PHA, it does not biodegrade easily in nature and must be mixed with food residues in industrial composters. Buried in a dump, it would take decades to disappear.
Critics of bioplastics produced from corn and sugar point out that they are exploiting arable land on a starving planet.
Ramani Narayan, who teaches chemical engineering at Michigan State University, has worked with different bioplastics companies over the years.
He believes that companies promote the “biodegradability” of their products to make them more attractive. But the word is “misused, overused and abused, because everything on Earth is biodegradable, given enough time and the right environment”.
He acknowledges that bioplastics degrade more easily than petrochemical plastics, which can take centuries to break down. However, it should not be overlooked, for example, that PHA degrades more slowly in cold water than in warmer weather.
“It’s going to take time, and it has to be said,” Narayan said.