The Plastic Problem

The Great Pacific Garbage Patch contains over 1.8 trillion pieces of plastic, and weighs over 100,000 tons. It covers an area over 1.6 million square kilometers- three times the area of France. The plastics that have made their way into the ocean will eventually break down into microplastics, and make their way into the lives of unsuspecting and unfortunate marine life. Studies on fish and other marine animals have shown that over 10% have plastics in their systems.

Polyethylene terephthalate (PET) is a kind of plastic used in an innumerable amount of products from water bottles to personal care product packaging. Most of the plastic that makes its way to pollute the ocean and other ecosystems is made of PET. A study showed that over 6.3 billion metric tons of plastic waste had been created by humans, and only a sad 9% of that plastic has been recycled. A main contributing factor to this plastic problem is the large volume of PET plastic bottles produced and used in the world. 1 million plastic bottles are sold every minute, and most of them are thrown away instead of recycled.

Our Goal

Researchers in Japan have recently found a bacteria, Ideonella sakaiensis, that eats PET plastic. PET can be broken down into ethylene glycol and terephthalic acid. We are taking the sequence for the enzyme that breaks down PET and putting it into an E. coli plasmid. Because of the toxicity of ethylene glycol, another sequence was created to let the bacteria obtain energy by breaking down the ethylene glycol and using it as the bacteria’s only carbon source. In the end, the bacteria will have transformed PET plastic into only terephthalic acid that can be recycled to be turned back into new plastics.

This year, Rose-Hulman’s Six Sigma club hosted a talk from ​Dr. Shikha Bhattacharyya, who discussed straw usage in the US and how to reduce it. After this, the school started offering biodegradable straws that were compostable. Although this is a great solution for plastic straws, there was still no solution to the plastic bottle problem. After researching the Ideonella sakaiensis, we realized that using bacteria was a promising way to tackle the plastic bottle problem.