Biosensors utilise the genetic circuits found in nature for sensing of particular substrates. In our case, we turned to ethylene-metabolising bacteria, specifically a local Australian strain of Mycobacterium known as Mycobacterium NBB4.
The regulatory genes behind ethylene metabolism in NBB4 are almost completely novel . Based on sequence homology and structural protein analysis, we've come up with two strong candidates - genes called EtnR1 and EtnR2 , which may interact with a putative promoter EtnP. Therefore, we had to check expression and characterise these regulatory components first!
If we want to use the regulatory aspects of NBB4 ethylene metabolism in a biosensor, we need to incorporate a reporter gene with strong, detectable output into our circuit. Generating such a reporter gene was the focus of EXPRESS, where we used error prone PCR on an existing blue iGEM chromoprotein amilCP to generate amilCP mutants with altered spectral characteristics
Putting SENSE and EXPRESS biocircuitry together, we can construct a usable biosensor with applications in cold shipping containers, supermarket store rooms and storage warehouses. We focused on the physical design aspects of a biosensor to bring to market, and performed detailed costings in a business plan for our biosensor.