Difference between revisions of "Team:Imperial College/Proof"

For our proof of concepts we decided to use chromoproteins as our visual demonstration of co-culture systems for consolidated bioprocessing. Chromoproteins are obtained from anthozoa and when expressed give out bright colour visible to the naked eye. We wanted to use chromoproteins as a proof of concept that co-culture cells at different ratio can be used to make product with varying compositions. In this case our products is colours of different shades and hues.

For our colour gene cosntructs, we went through the iGEM distribution kit and found coding sequences of different chromoproteins, seven of which we decided to use.
These are spisPink, amajLime, amilGFP, fwYellow, eforRed, gfasPurple and cjBlue.

We assemble these coding sequences with an RBS part with a built-in Anderson promoter and a terminator. We next transformed these constructs into top ten cells for characterisation.

We first mixed these coloured cells manually to demonstrate that different ratio of chromoproteins can produce different colours. These are demonstrated in the table below.

Figure 1: Picture of the different colours obtain by manually mixing different ratios of colored cells.

We also investigate the growth rate of cells expressing different chromoproteins. This is to show that the different metabolic burdens impose by the productions of different proteins can affect the growth rate of the cells. This can lead to instability of the co-culture.

Figure 2: Plot of Growth rate versus time for Escherichia coli Top 10 cells expressing various color constructs.

We picked a chromoprotein that does not effect growth as much as the others and ligated in our arabinose inducible gp2 construct. This gp2 construct allow us to control the growth of the coloured cells and provide a way to maintain a stable co-culture.

Figure 3: Plot of Growth rate versus time for the eforRed with growth control gp2 construct Escherichia coli Top 10 cells.