Plastics: Biodegradable, Bio-based, or Compostable?

Conventional plastics are widely recognised as harmful to the environment, but are the alternatives any more eco-friendly?

MORE than 99% of the world’s plastics are currently made using limited fossil-resources.¹ Global plastics production accounted for an estimated 2.24 Gt of CO2e in 2019,² while 20m t of the 460m t/y of plastic produced ended up in the environment as plastic litter.

Concerned about the impact of these materials, consumers are increasingly seeking out more environmentally friendly alternatives, with producers meeting this demand with labels such as bio-based, biodegradable, and compostable.

But what do these terms actually mean?

Bio-based plastic

Instead of fossil resources, bio-based plastics are made fully or in part from biomass. Currently, they are made primarily using crops such as corn or sugarcane, but progress is being made on alternatives made using feedstock such as trees and algae, as well as agricultural and other wastes.

These alternatives can be made with identical properties to conventional versions such as bio-based polyethylene (PE) and polyethylene terephthalate (PET), allowing them to act as drop-in solutions with a lower carbon footprint. However, this can come at a price, with negative agricultural impacts, competition with the food system, unclear end-of-life management, and higher costs the payoffs. Because they can be designed identically to conventional counterparts, they also pose end-of-life pollution threats.

Bioplastics

The term bioplastic can be used to refer to plastics that are bio-based, biodegradable, or both. Examples of plastics that are both bio-based and biodegradable include poly-3-hydroxybutyrate (P3HB), polyglycolic acid (PGA), and polylactic acid (PLA).