Contamination of aquatic bodies has been one of the biggest environmental concerns, intensifying due to population growth and the production of hazardous waste that causes contamination of the air, soil and water, which consequently puts the lives of various organisms in an ecosystem at risk.

Aquatic pollutants are diverse and can be released into the environment in different ways, whether in the form of toxic fumes, suspended particles or liquids. These compounds are mainly concentrated where there is the greatest anthropological influence, raising numerous issues relevant to the ecosystem and human health that intensify the challenges of applying conventional treatment technologies.

Background

Microplastics

Microplastics are tiny particles of plastic, usually less than 5 mm in size, resulting from the fragmentation of larger plastics. They have emerged as one of the main pollutants in both aquatic and terrestrial environments. The presence of these particles disrupts the biochemical composition of ecosystems, exerting a detrimental impact on the region and, consequently, affecting human health when they are ingested or inhaled².

Microplastics, when present in the environment, act as captors of Persistent Organic Pollutants, which are highly harmful and toxic, being linked to hormonal, immunological and reproductive dysfunctions in fauna, flora, microbiota and human health³.

There are currently two classifications of plastics: thermoplastics and thermosets⁴.

• Thermoplastics: Thermoplastics are those that soften when subjected to high temperatures, but then harden. They then cool and harden, and account for more than 80% of plastics on the market.
• Thermosets: These are plastics that harden through the hardening process and, after that, cannot be melted or re-melted. They cannot be remelted or remolded and make up the remaining 20% of the market.

The use of plastic in the world has experienced substantial growth in recent decades, driven by a combination of economic, technological and convenience factors. According to data from the International Association of Plastics Manufacturers (IAPMO) report, global plastic consumption has increased considerably, reaching approximately 368 million tons in 20195. This increase can be attributed in part to plastic's versatility as a low-cost, easy-to-process material, making it ideal for a wide range of industrial applications, from packaging to electronics and medical devices.

In addition, growing urbanization and changing consumption patterns, especially in emerging economies, have also contributed to the increased demand for plastics. However, this increase in plastic use has generated significant concerns regarding waste management and the associated environmental impacts, such as microplastic pollution and the accumulation of plastic waste in sensitive ecosystems. Therefore, the current challenge is to find sustainable solutions to reduce excessive plastic consumption and promote more environmentally friendly alternatives⁵.

Polyethylene terephthalate (PET) is a polymer widely used in packaging, bottles for food and hospital products, cosmetics, microwave trays and other products. Its popularity is due to its transparency, resistance, impermeability and lightness. PET is recyclable, but its main disadvantage is that it is produced from oil, a non-renewable energy source⁶.

Furthermore, when combined with other materials, such as cotton fibers in clothing and footwear, recycling PET becomes a complex task, negatively impacting our collective effort to promote environmental sustainability.

Challenges

Among the many damages caused to the environment, one is related to plastic waste. This waste generally takes a long time to degrade spontaneously and, when burned, produces toxic fumes. With the growing use of these materials, especially in the area of packaging, which is disposed of very quickly, environmental problems are worsening, even damaging the lifespan of landfills⁷.

Contamination caused by plastics around the world has become a growing concern, as these persistent and ubiquitous materials have significant impacts on ecosystems and human health. Plastic contamination rates are alarming, and the numbers continue to rise.

Microplastics are one of the most worrying forms of contamination. It is estimated that up to 51 trillion microplastic particles are present in the oceans, posing a serious threat to marine life⁸. Each year, between 4.8 and 12.7 million tons of plastic enter the world's oceans, affecting marine life, causing accidental ingestion of plastic by marine animals and degradation of coastal ecosystems⁹. These particles are ingested by a variety of marine organisms, from zooplankton to marine mammals, and can cause obstruction in the digestive tract, nutritional deficiencies and even the death of marine animals¹⁰.

The lack of effective waste management systems and the improper disposal of plastic are significant problems in many parts of the world. A substantial portion of plastic ends up in rivers and oceans due to improper disposal practices⁹. Collecting and removing plastic from the oceans is a complex and costly operation. The vastness of the oceans, the dispersion of plastic and adverse weather conditions make clean-up a significant technological challenge¹¹.

Reducing the amount of plastic in the oceans is a challenging and complex task due to a number of interconnected factors that contribute to the persistence of plastic pollution. Addressing these challenges requires a coordinated global effort involving governments, industry, environmental organizations and society at large. Effective strategies to reduce plastic pollution in the oceans include promoting recycling, implementing regulations to limit the production of single-use plastic, public education about the impact of plastic and the development of sustainable alternatives to conventional plastic.

Regional contextualization

Paraná, one of Brazil's 27 federal units, stands out geographically as the first of the three in the southern region of the country, subdivided into 399 municipalities. With its water bodies covering 199,315 km², the state is able to supply around 345 municipalities, playing a vital role in nourishing the region's major rivers and basins (RPC, 2019).

The city of Foz do Iguaçu is located in the far west of the western mesoregion of Paraná, Foz do Iguaçu, at an altitude of 173 meters, with a total area of 618.352 km² and a population of 263,915 inhabitants. (IBGE, 2016) The word ''Foz do Iguaçu'' derives from the Tupi-Guarani language - a language spoken among the indigenous tribes that inhabited the region at the time - and can be divided into: ü (water, river) and wa'su (big), i.e. a "flowing river", highlighting the importance of the union of the region's main rivers: the Paraná River, and the Iguaçu River.

The city is an important international tourist destination, famous for the Iguaçu Falls, considered one of the 7 wonders of the world, and for the Itaipu Hydroelectric Power Plant, the largest producer of hydroelectric power in the world.

Despite being one of Brazil's main tourist destinations, Foz do Iguaçu faces environmental problems, such as the pollution of the Iguaçu River, considered the second most polluted body of water in the country since 2008. (IBGE 2008)

In addition, marine plastic pollution is a growing concern, with more than 48% of objects found in Brazilian seas being made of plastic materials. These issues threaten the region's fauna and flora, as well as compromising water quality and the natural beauty of lakes and rivers. This situation highlights the urgent need for coordinated action, including awareness-raising measures, regulations to reduce the use of single-use plastics, incentives for recycling and the adoption of sustainable alternatives. Only through joint efforts can we protect our precious aquatic ecosystems and ensure a healthy future for the water bodies of Brazil and the world.

MHETYGUÁ

UNILA-LatAm

The UNILA-LatAm team is made up of students from the Federal University of Latin American Integration, consisting of 6 countries: Bolivia, Argentina, Colombia, Peru, Paraguay and Brazil. With this multidisciplinary perspective the group aims to disseminate Synthetic Biology in order to raise awareness of the technical and bioethical aspects of the use of genetically modified organisms in the development of new technologies and the resolution of local problems. In the city of Foz do Iguaçu and neighboring cities of the triple border region between Brazil, Argentina and Paraguay. See more about the team members here

As an emerging sector in Latin America and other developing regions, this perspective pushes beginners to design and develop strategies taking into account ethical and practical responsibilities, strengthen community participation in the scientific area, and promote critical reflections from interactions with the local population. The importance of the area is reflected in its growing participation in technological development, providing sustainable, low-cost and efficient answers to solve global problems and challenges.

Project goals

For the IGEM Global 2023 edition, the group of students is aiming to take part in the competition with the project entitled "MHETYGUÁ: algae as devices for the degradation of aquatic pollutants" in order to encourage Latin American teams to develop synthetic biology projects and create a multidisciplinary learning space for the participants.

Microplastics represent a significant challenge in terms of environmental pollution and have raised concern all over the world; they are found in rivers, lakes, oceans, and even groundwater, harming aquatic ecosystems and threatening human health. To address this challenge, our team is focused on developing an innovative solution based on the use of algae.

Besides the development of this solution itself, we are working on the front of promoting awareness about microplastics and their impacts, and for this focus we are creating and developing an educational platform aimed at teachers of any school network, working with children from elementary school and high school. Through this platform we disseminate video lessons and tools such as dynamics and a board game we created with the theme of water pollutants. Thus increasing public understanding of the importance of reducing the use of plastic, of proper disposal, and of preserving aquatic ecosystems. See more about the Education wiki page here

Algae as a degradation device

Algae are photosynthetic organisms that play a vital role in aquatic ecosystems by contributing to oxygen production and water purification, we believe we can harness the potential of algae to effectively combat microplastics.

The project MHETYGUÁ focuses on using the microalgae Chlamydomonas reinhardtii as a tool for microplastic degradation. We aim to engineer this alga using synthetic biology techniques to introduce genes responsible for producing plastic-degrading enzymes such as Fast-PETase and MHETase, in addition to the use of a flexible 12-amino acid linker that increases the catalytic activity and secretion of the products. These enzymes have the ability to break the chemical bonds of microplastics, transforming them into less harmful by products. Read more about our design project here

The choice of microalgae as our chassis is driven by its simple structure, ease of manipulation and maintenance, and potential for biomolecule studies have made it an excellent model organism for studying photosynthesis, genetics, cell biology, and biogenesis, and it has demonstrated the ability to adhere naturally to PET microparticles.

Through the MHETYGUÁ project, we aspire to contribute to the reduction of microplastic-related problems in the Foz do Iguaçu region and promote environmental awareness

References

• Ibrahim, R.K., Hayyan, M., AlSaadi, M.A. et al. Aplicação ambiental da nanotecnologia: ar, solo e água. Environ Sci Pollut Res 23, 13754–13788 (2016). https://doi.org/10.1007/s11356-016-6457-z.
• Silva, Pablo Pena Gandara. Contaminação e toxicidade de microplásticos em uma área de proteção marinha costeira. Diss. Universidade de São Paulo, 2016.
• Belo, I.C.B; Andrade, B.N.P; Miranda, J.P.A; Drumond, P.C. Microplásticos, seus Impactos no Ambiente e Maneiras Biodegradáveis de Substituição. Revista Internacional de Ciências, Rio de Janeiro, v. 11, n. 02, p. 214-228, 2021. DOI: 10.12957/ric.2021.54481
• Zea, J.J.G.B. Reciclado de Plástico PET. Facultad de Ingenierías y Computación, Arequipa, 2019.
• Associação Internacional de Produtores de Plástico (IAPMO). Relatório de Consumo Global de Plástico, 2019.
• Nascimento, C.R; Dias, M.L. Solid state polymerization of recycled PET - The influence of chain extenders on the increase of molecular weight and the thermal properties. Macromolecules Institute, Rio de Janeiro.
• Gonçalves-Dias, S. L. F; Teodósio, A.S.S. Structure of the reverse chain: "ways" of PET packing. Scielo, v. 16, p. 429-441, 2006.
• Thompson, R. C., et al. (2004). Lost at sea: Where is all the plastic? Science, 304(5672), 838.
• Jambeck, J. R., et al. (2015). Plastic waste inputs from land into the ocean. Science, 347(6223), 768-771.
• Wright, S. L., et al. (2013). The physical impacts of microplastics on marine organisms: A review. Environmental Pollution, 178, 483-492.
• Galgani, F., et al. (2019). Evaluating scenarios toward zero plastic pollution. Science, 364(6436), 239-241.