Our project, "Knockout Nitrate", is a developing project with the aim to use synthetic biology to balance the nitrogen cycle.
Background
Nitrogen is a highly abundant element in the Earth’s atmosphere. Nitrogen is also essential for life. However, atmospheric nitrogen (N2) is not useful in living processes. Humans have developed processes to convert unreactive atmospheric nitrogen into a usable form of nitrogen such as Ammonia or Nitrate for plants and animals (reactive nitrogen). To maximize crop yield, many farmers add nitrogen based fertilizer to their crops. Oftentimes excess nitrogen in the soil is washed away by rain into other natural water systems. This nitrogen runoff can and does have devastating effects on the biodiversity in waterways.
To read more background information about the nitrate problem, click the image below.
Project Design
In order to combat the nitrate problem, we aimed to design a strain of E. coli capable of reducing these excess nitrate ions. By isolating a gene that codes of periplasmic nitrate reductases, we began the process of designing our synthetic organism.
To read more information about the design of our system, click the image below.
Experiments for Our System
Throughout the summer and into the fall, we implemented our design into the laboratory. We isolated and synthesized our periplasmic nitrate reductase genes, as well as developed a kill switch and safety-assurance cases
To read more information on the application of our design, click the image below.
Recharacterization of K381001
In the design of our project, we implemented a nitrate-sensitive kill switch. This took advantage of the fact that the yeaR promoter, originally submitted by the Edinburgh iGEM Team in 2009 (K216005) was active only in the presence of nitrate ion. We decided to begin our project by determining sensitivity of this promoter the concentrations of nitrate that would be present in waterways. To do this, we recharacterized the composite part K381001, a PyeaR-GFP nitrate sensor. You can read more about our rechracterization of the PyeaR-GFP Biobrick Here.
