Project Description

The Problem

Algal bloom
In the Chesapeake Bay and Hudson River, fertilizer runoff is one of the primary pollutants. Fertilizer runoff contains phosphate, which is very dangerous to the environment in high concentrations because it causes a dangerous growth of algae, forming algal blooms. These blooms produce dangerous toxins and decrease the oxygen present in the environment, resulting in dead zones. Unfortunately, plants do not uptake enough of this phosphorus in the environment and plants cannot easily use the phosphorus in its inorganic and poorly soluble state as the mineral compounds cadmium phosphate and calcium phosphate. Local organizations like the Chesapeake Bay Foundation are working to create policies that limit the usage of fertilizer to prevent further runoff and damage to the Bay. But, these policies may not be enough on their own, and they do not address the inorganic phosphate pollution that is already in the Bay and isn’t going away.

Our Project

In light of this, our team decided to engineer the uptake of phosphate in Rhizobacteria and the plants they have a mutualistic relationship with. Rhizobium naturally has a symbiotic relationship with plants, so if we could engineer it to solubilize phosphate, it could provide previously unavailable phosphate for plants' use..

Plant roots with nodules indicating presence of Rhizobium
Plant roots with nodules indicating presence of Rhizobium

Why We Chose This Project

When deciding on our project, our team went through several rounds of voting to settle on a specific topic. We wanted to approach an issue that affected both portions of our team, the portion in the Baltimore area associated with the community lab Baltimore Underground Science Space (BUGSS) and the portion in the New York area associated with the community lab Genspace. We also wanted to be sure that synthetic biology would be a useful and effective way of addressing whatever issue we chose. We decided to address phosphate pollution since it is such a huge issue on the East Coast. Additionally, phosphate pollution has occurred at its scale because of human mismanagement: human error damaged the environment, which is not equipped to counteract it. This is why we believe that synthetic biology—a solution inspired by and designed with nature—is the best solution.

However, our team not only wanted to address the issue of phosphate pollution, we also wanted to address this issue in a way that would be specific to New York and Baltimore. These areas are both coastal cities, and as such, they are especially susceptible to flooding. As climate change intensifies, there is an ever-increasing concern about the threat of flooding, especially in coastal areas. Many people have proposed increasing cities’ “sponginess” (the use of nature to combat susceptibility to flooding in urban areas) as a way of combating the risk of flooding. Our project will use plants to capture the phosphorus before it can get to the Bay or Hudson River and we will build floating wetlands to combat the phosphorus already in the water. Together these will contribute to the vision of a “spongier” Baltimore and New York City in the face of climate threats.

Baltimore sealine


There are many teams whose work we have looked to for inspiration, such as Düsseldorf 2020, Bath 2022, Brno 2021, Purdue 2016, Qdai 2020, Tacoma 2019, and the 2015 and 2016 Yale teams. One of the most important teams that we have looked to is Thessaly 2022 since they used a floating wetland with engineered native plants for phosphate uptake. They worked on creating genetically modified plants (, which we felt might be too ambitious for us given our limited time and resources. So instead we chose to use bacteria that are symbiotic with plant roots, Rhizobium, and genetically engineer those. But, we are inspired by their work with floating wetlands and are considering these to address not only the phosphate in soil before it reaches waterways but to clean up waterways after they are already contaminated.


Chesapeake Bay Foundation. (n.d.). Phosphorus Management. Chesapeake Bay Foundation. Retrieved June 27, 2023, from phosphorus-management-tool.html#
iGEM 2019 Tacoma. (n.d.). Project description. 2019 iGEM Tacoma. Retrieved June 27, 2023, from
iGEM 2020 Duesseldorf. (n.d.). Project description. iGEM 2020 Duesseldorf. Retrieved June 27, 2023, from
iGEM Thessaly. (2022). Project description. 2022 iGEM Wiki. Retrieved June 27, 2023, from
The New York State Department of Environmental Conservation. (n.d.). Lawn fertilizer (NYS nutrient runoff law). New York State. Retrieved June 27, 2023, from 67239.html
Nielsen, P. H., Mcilroy, S. J., Albertsen, M., & Nierychlo, M. (2019). Re-evaluating the microbiology of the enhanced biological phosphorus removal process. Current Opinion in Biotechnology, 57, 111-118.
United Nations. (n.d.). Water—at the center of a climate crisis. United Nations. Retrieved June 27, 2023, from