In 2012, the U.S. discarded 32 million tons of plastic; fewer than 3 million tons of these plastics were recovered and recycled. The 29 million tons of plastic that were discarded in 2012 still exist in the environment today. In fact, discounting plastics that have been burned, all plastics that have been produced since the technology’s development in the 1950s continue to exist in our world and will continue to exist for hundreds of years to come. But these plastics are not simply existing; they are fundamentally altering the natural environment, especially the marine biome. In the early 1970s, scientists first reported the existence of plastic litter in the world’s oceans. Initial environmental research focused on macroplastic waste and the associated side effects, such as entanglement of and ingestion by marine wildlife, transport of non-native species, and seabed smothering. However, in the past ten years microplastics have begun to garner increasing attention. Microplastics are defined as plastic fragments less than five millimeters in length. They can enter the ocean via wastewater or be produced by degrading macroplastic. Once in the sea, microplastics accumulate toxins and, when ingested by zooplankton, leak plasticisers and the aforementioned contaminants. States are beginning to acknowledge this growing problem, and Illinois has banned microplastics in cosmetics.
Due to the growing problem of microplastics in the environment, our team is engineering a biological microplastics filter for implementation in wastewater treatment plants. The filter is composed of E.coli K-12 that have been engineered to catch and degrade microplastics in the water supply. To degrade microplastics, a plasmid that codes for manganese peroxidase has been inserted into the bacteria. Manganese peroxidase, an enzyme which naturally occurs in the fungus Phanerochaete chrysosporium, has been shown to degrade nylon. Our bacteria will secrete the manganese peroxidase into the surrounding water to break down the nylon microplastics. The bacteria will also have the ability to form a biofilm. By upregulating the transcriptional regulator, NhaR, we can cause the overproduction of an exopolysaccharide. These exopolysaccharides allow bacteria to attach to foreign surfaces as well as one another, forming a biofilm to trap microplastics with the manganese peroxidase. Although our current filter solely degrades nylon microplastics in wastewater, we believe that this should not be the last stage on our filter’s development. By engineering a non-pathogenic bacteria to form a biofilm, we believe that other plastic degrading plasmids from the iGEM registry could be implemented in the same filter. This addition would allow for the optimization of a filter that could degrade all microplastics in the water supply.
While our team believes that this biological filter is a viable solution to the microplastics problem, we wanted to gauge the public’s acceptance of our project, as well as their awareness of synthetic biology in general. Our human practices team developed a survey for distribution by iGEM teams worldwide. Over 50 other iGEM teams participated and gathered over 900 responses. We have also continued the 2013 VGEM team’s work with local high schools, mentored the Renaissance iGEM team, and taught a synthetic biology crash course at the Math, Engineering and Science Academy. We hosted a competition which encouraged high school students to research what synthetic biology can do for them in the fall of 2014. We exhibited their poster submissions at a synthetic biology panel to inform the public about synthetic biology issues.
See Virginia 2014's project wiki for more details.
Back row: Zi Ye (BME 2015), Haider Inam (BME 2016), Fangcheng Yuan (Biochemistry 2016), Alexander Schmitt (Biology 2015), Dr. Keith Kozminski (Project Advisor), Michelle Yao (Computer Science 2016), Joshua Leehan (Biology 2015) Front row: Matthew Tucker (ChE 2015), Thomas Moss (Biology 2017), Grace Mantus (Biology 2016), Cara Broshkevitch (BME 2017)