Results - Blue Light

We decided to develop a photo-inducible genetic circuit that triggers the production of Ethylene in presence of blue light (470 nm), and stops at dark.

We thought to use blue light as our inducer because it would fit perfectly to our very own B. fruity vending machine, being the easiest way to control a genetic device in a totally automated scaffold. All parts have been transformed and characterized in E. coli (strain NEB10b).

The device

We aimed at first to get ethylene production at blue light (470 nm) and the off state at dark, so we went for the design of a blue light dependent device that includes an inverter cassette.

BBa_K10653010

We engineered in E. coli a blue-light sensor composed by:

• Anderson promoter BBa_J23100;
• the blue light receptor YF1, which consist of YtvA from B. subtilis fused to a kinase domain (fixL) from B. japonicum (Möglich A, Ayers RA, Moffat K. 2008);
• its response regulator, FixJ;
• a downstream promoter PfixK2, which is turned off by phosphorylated FixJ;
• an inverter cassette composed of cI and Plambda;
• a reporter (chromoprotein amilCP), which was later substituted by EFE (our ethylene forming enzyme);