Violacein Pigments


Proof of pigment production

Successful Pigment Production

We transformed Top10 with pPSX-Vio+. After three colour eventually appeared, as shown below. Interestingly, the pigment appears to remain within the bacteria, with little or no bleeding into the media. We took the violacein pigment bacteria (right plate in photo) out of the fridge to find that the purple colour had started to develop. They were therefore left at room temperature overnight. The colour appears to be within the bacteria, with little or no bleeding into the media. The control plate (left plate) is the untransformed TOP10 E. coli.

Cambridge Violacein Pigment.jpg

Left: control plate - untransformed TOP10 E. coli, Right: Top10 transformed with pPSX-Vio+.

Multiple Pigment Production from the Violacein operon

Top10 transformed with the DNA we received from DNA2.0 showed vibrant pigment production.

Cam09 vio.jpgCam09 vio1.jpg

Left: Violacein growth on agar plate (overnight). Right: Single colonies.

Further, we were able to remove VioC or VioD from the operon to produce a green pigment.

Cam09 gre.jpgCam09 gre1.jpg

Left: Lawn of green bacteria on agar plate (overnight), derived by removing one gene from the violacein cassette. Right: Green colonies on agar plate.

Characterisation of colour output

We characterised the violacein pigment by carrying out the acetone extraction protocol used for carotene. The results were normalised for OD and then plotted as a graph of absorption units against wavelength:

Vio wavelength graph.JPG

We also looked at absorbance at 584nm (the maximum absorbance for violacein):

Vio absorbance.JPG

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