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Background

The problem

Microplastic pollution has become more serious due to the rapid growth of the plastic production. It was estimated that global production of plastics is approximately 250 million tons per year(1). Plastics are inexpensive and durable, and as a result levels of plastic production by humans are high. Since we produce over 300 million tons of plastic every year and almost 90% of the plastics are not recycled(2). They are decomposed into microplastics, small plastic pieces less than five millimeters in diameter, which brings severe problems to our planet.

Hazards to Wildlife

First, the marine animals' lives are greatly endangered. Since microplastics are blown into ocean, lakes and 8 million tons of plastics are thrown into the ocean every year. Sunlight, wind, waves, and heat break down plastics into microplastics. Polymer degradation takes much longer as a result of saline environments and the cooling effect of the sea. The Marine Conservancy has predicted the decomposition rates of several plastic products. It is estimated that a plastic beverage holder will take 400 years, a disposable nappy will take 450 years, and fishing line will take 600 years to degrade(3). After ingested, they block animals' digestive tracts, diminish the urge to eat which reduce growth and reproductive output. For example, over a million seabirds has been estimated to be dying from plastic ingestion each year(4). Moreover, hundreds of sea turtles die every year after they become entangled in plastic wastes. Thus, various marine animals are endangered which decreases biodiversity and simplers the food web.

Hazards to humans

Second, it may cause health problems to Humans. After microplastics entered the terrestial and aquatic food chains, humans may absorb microplastics through ingestion and breathing. A 2017 study reported that 83% of tap water samples taken around the world contained plastic pollutants(5). People may ingest at most 4,000 microparticles of plastic from tap water per year! Some of these microplastics are considered endocrine disruptors—chemicals that interfere with normal hormone function. Other compounds that cling to plastics can cause cancer or birth defects. Children and women at reproduction age are prone to have their immune system and reproductive system harmed by these hormone-disrupting chemicals. Our project aims at the severe microplastics pollution and we try to solve this problem by chemically breakdown Polyethylene terephthalate (PET), one of the most common ones.

Project Inspiration

Everyone knows that plastic pollution has become one of the most pressing environmental issues, as rapidly increasing production of disposable plastic products overwhelms the world’s ability to deal with them. It brings numerous long-term impacts.

Threatens marine animals

With at least 8 million tons of plastic end up in the sea every year(6), you can imagine how serious is the problem of microplastics is. Millions of animals are killed by plastics every year, from whales to fish to other marine organisms. Most of the deaths to animals are caused by entanglement or starvation. Seals, whales, turtles, and other animals are strangled by abandoned fishing gear or discarded six-pack rings. The World Wildlife Foundation warned that plastic pollution is one of the most dangerous threats to sea life, noting that five whales have been killed by plastic over a two-year period(7). Microplastics have been found in more than 100 aquatic species, including fish, shrimp, and mussels destined for our dinner plates. Thus, the problem of microplastic threatens both marine animals and us.

Impact on food and health

As the plastics are broken down during the process of photo-degradation, chemical substances that may be used to make plastics will be released to the ocean. Meanwhile, thinner plastics will absorb all the chemical substances on the ocean surface, including carcinogens human beings discharge into the sea.It has also been thought that microplastics can act as a vector for pathogens as well as heavy metals(8). Photo-degraded plastics can be easily absorbed by the digestive system of fish and seabirds. Many toxic chemical substances, therefore, enter the food chain, causing unpredictable disaster to the ecosystem. Larger-volume plastic products may also choke the digestive system of saltwater fish and seabirds(9), which will then die of malnutrition. Thus, resulting in, the top predator in the ocean and human will be affected. We cannot watch this alarming phenomenon with folded arms. Hence, we are here to try our utmost to solve the plastic pollution through synthetic biology like making the bivalves to digest the plastic.

Synbio Solution

To break down Polyethylene terephthalate (PET), we provide an effective way to degrade microplastics by using cutinases. Being a novel way to break down PET, cutinases are very efficient. In potential applications & biosafety consideration, we can introduce GM bacteria which can produce cutinases for water purification.