The manufacturing of plastic, simply put, is the conversion and processing of fossil fuels (hydrocarbons) into polymer resins. Once as a resin, it is heated, cooled and molded into the desirable end product. In 2015, a rubbish report was released that identified that plastic is 36% of all rubbish waste in Australia; an increase from 30% the year before. With Australia producing over 18 millions tonnes of waste per year, that is approximately 6,480,000 tonnes of it being plastic. Most plastic takes up to 450 years to decompose with some bottles taking up to 1,000 years. The negative effects of plastic manufacturing and waste is the increase in carbon dioxide emissions (contributing to global warming), increased chance of flooding and the death of wildlife so what are we doing? Caterpillars might be the answer.
Of all of the plastics, 92% consist of types made of polyethylene and polypropylene. The main issue with these types of plastics is the hydrocarbons (a compound of carbon and hydrogen) which are very resistance to being broken down. Some tests of trying to break down these plastics has involved fungus and bacteria but these are incredibly slow processes. The fastest breakdown of plastic comes in the form of a larva called the wax worm that grows to become the snout moth. The study found that when left with direct contact with the plastic bags, approximately 100 worms can eat up to 92 milligrams of plastic over 12 hours. Though small, this rate of biodegradation is significantly higher than than rate of fungus or microbial breakdown.
They way in which they breakdown the plastic might simply be because of their natural physiology. Wax worms feed on the wax in honey combs which consists of lipids (fats) put together in a complex fashion. Though complex, there are still carbon bonds within the wax so the worm must break these down to be able to ingest the wax. It is the similarity between the wax and plastic structure that allows these worms to eat away at the plastic wastes left by us. This is all very cool but we’re not going to start scattering these worms over garbage heaps, that would be silly because the crows would eat them. What scientists are looking to further investigate is the enzyme and chemical mechanisms that occur within the caterpillar that will be able to degrade plastic bag waste. Who knows, in the next 15 years we might have an aerosol that we spray on plastic waste to break it down into no hazardous products. Wouldn’t that be nice?