Can plastic-eating super enzymes solve our destructive plastic problem?
8 April 2022
In the circular economy in the last few decades, the manufacture of low-cost, durable, and adaptable plastics has expanded. They have infiltrated every aspect of our lives; nonetheless, this once-desirable material has a bad side. Plastic pollution is one of the most challenging environmental concerns facing today, climate change. Estimated 150 million tons of plastic are disposed of or released into the environment each year, with over 8 million tons transported into the world’s oceans by rivers. The mass of this does not disintegrate and instead degrades into microparticles. These well-documented microplastics have been identified in ocean water, marine species, and even deep within human gastroenterology. Pollution from plastic is one of the most dangerous environmental concerns confronting humanity today, and scientists have been working hard to find solutions to this difficult problem.
Solving the polymer recycling conundrum by depolymerization
Polymers are lengthy chains made up of repeated monomer blocks that make up plastics. The majority of commonly used polymers are thermoplastic or thermosetting. Acrylic, polyamide, and polyethylene are thermoplastics that become soft and moldable at high temperatures and solidify when cooled. Because they may be softened and remolded into new items, they are reasonably straightforward to recycle, albeit quality decline limits the advantage. Plastics that solidify when heated, such as polyurethane, epoxy resin, and melamine resin, are nearly impossible to recycle. Due to the difficulties in recycling thermoplastics and thermosets, all plastics will eventually contribute to environmental contamination.
- Waste plastics must be restored to their original monomers through a process known as depolymerization to be recycled and reused in new products. This is a crucial technological advancement that will allow for the creation of a global circular materials economy. Complete depolymerization to monomers may be required for microbial uptake and growth in biological systems.
- Scientists have looked to nature for microbial enzymes that can break down plastics to achieve depolymerization.
The leaf-branch compost cutinizes (LLC) enzyme dissolves the bonds between PET monomers. Still, it is intolerant of PET’s softening temperature of 65°C, denaturing after a few days and restricting its industrial viability. Enzymes must be stable at high temperatures since depolymerization can only occur in molten plastic.