Microbiology’s opportunity to solve the plastic waste problem

After the publication of Blue Planet II, a David Attenborough-narrated television series that focuses on the effects of human activity on the marine environment, the public’s appetite for decreasing plastic trash has grown insatiable.

Delegates heard from Professor Kevin O’Connor, a renowned principal investigator at University College Dublin, during the Microbiology Society’s Annual Conference in 2018. He addressed ways to lessen plastic waste, consumer confusion, and potential for the future in his address, “Plastic trash: A worldwide problem and a chance for microbiology.”

The problem with plastic

Globally, plastic is employed in billions of products because of its adaptability, and by 2035, we’ll likely create more than 600 million tonnes of it. In Europe, the manufacture of plastics supports 1.5 million jobs, and by enabling the construction of more durable and lightweight automobiles and better-insulated homes, plastics significantly contribute to the reduction of greenhouse gasses (GHGs).

The creation and burning of plastic, however, is responsible for about 400 million tonnes of carbon dioxide emissions each year, and single-use plastics are significant terrestrial and marine pollutants. The need for alternative materials or plastic management techniques is great. Why isn’t there an effective recycling system in place when many customers are already aware that plastics are recyclable? More regions have even lower recycling rates than Europe, where less than 30% of all plastic garbage is now collected for recycling. This can be a result of the lower product quality and inferior aesthetics of recycled plastics compared to virgin plastics.

The majority of marine debris is made of plastic. The majority of beach litter is made up of single-use items including straws, coffee cup lids, plastic bottles, and plastic bags. It can take up to a thousand years for PET plastic bottles and containers to decompose in the environment.

Microplastics are also a significant problem. Microplastics, which are defined as plastics with a length of fewer than 5 millimeters, can be created in a number of ways, such as through the degradation of larger waste, or they can be manufactured as micro-beads for use as exfoliants in cosmetic goods like cleansers and toothpaste. These tiny particles frequently bypass water filtration systems and end up in lakes and seas. Because they can be mistaken for food by smaller fish and eventually make their way into the food chain in the intestines of fish we eat, microplastics can cause significant harm to aquatic life.

If we can’t stop people from using plastics, society should attempt to cut back on their use. Is so much packaging really necessary? How may plastics be created to facilitate reusing them?

Combating plastic waste

Kevin and his crew started looking into the recycling of plastic waste made from petrochemicals in 1999. They employed pyrolysis, a technique for a thermal breakdown that breaks down petrochemical plastic polymers into their monomers or precursors. After that, Pseudomonas putida, a bacteria, was fed these monomers. The bacteria created polyhydroxyalkanoates, which are biodegradable plastic polymers, after digesting the petroplastic monomers (PHAs). PHAs have been demonstrated to perform as well as or better than petrochemical polymers used in items like glues, making them a viable alternative for usage in things like post-it notes. They also degrade in the environment without leaving behind any toxic byproducts.

Biodegradable polymers were another area of focus for Kevin’s team, along with how well they degraded in controlled and uncontrolled situations. These included composting in the industrial, residential, and maritime sectors, each of which has its own criteria for composting. varying from industrial procedures, where plastics must break down after 180 days at about 50°C, to marine processes, where plastics must break down after 56 days at 30°C.

It was discovered that the rate of deterioration of various plastics, even those belonging to the same polymer family, varies significantly depending on the environment. Polylactic acid (PLA), the biodegradable plastic with the fastest market growth in the consumer sector, does not break down at all in the 28°C conditions present in home composting. Similarly to this, many plastics don’t break down well in the ocean. However, with a properly-managed industrial composting technique, biodegradable.