Genetic Switch for Bioproduction

Bioproduction is a process of great industrial interest that generates useful products through microorganisms. The most common system for control of the bioproduction is the use of chemical induction compounds (like IPTG and arabinose) that are, not only expensive, but also lacks fine control of induction. Our goal is to build a genetic circuit that can switch between two different states of activation with just a single input of blue LED light. The system was built in E. coli and works based on DNA-protein repression loops, recombinases capable to invert the DNA orientation of a promoter region and a light-responsive genetic circuit. In addition, fluorescent proteins such as GFP, RFP and YFP function as output for our circuit. We also aim to compare the efficiency between light-induced promoters to chemical-ones, by evaluating strength and leak. With this circuit, it is our goal to make bioproduction more practical, controlled and economical.

Light is an easy to use, precise inductor. As a signal it depends on the wavelength, intensity and the receptor, in our case a protein that recognize a specific wavelength. This gives a very specific and controlled signal to control gene expression. Besides that, light can be activated instantaneously, simply by turning on its source. Further, to stop the induction, it’s not necessary to change or wash the culture media, a process that can make some bio-production processes impossible. Using light opens new possibilities for this industry.

To make bioproduction an optimized process, a switch would be useful to regulate gene expression at two different stages. For example, to produce two different compounds switching back and forth between the two, to get to an optimum. Another example is to use the switch to alternate between growth of the bacteria culture and production of the compound of interest. This allows testing different combinations of growth time and compound biosynthesis activation to get the maximum yield, like shown in this case