Team:CIDEB-UANL Mexico/project abstract

iGEM CIDEB 2014 team’s project is a bio-filter of sodium ions in salt water. In order to work and test the different processes of the project, it was divided into four modules, which also made up the acronym of our project’s name: Capture, Aroma, Resistance, and Union. Capture module is in charge of recollecting sodium ions in the water due to the new NhaS gen registered by the team. Aroma module is with the help of salicylic acid, responsible of producing a Winter Green odor that acts as a reporter if the bio-filter is working. Resistance module allows the E. coli to survive in the salty environment of the water, and this allows the bio-filter to works. Finally, the Union module allow the bacterium to joins to a silica pearl, which facilitates the removal of the bacteria from the water.

Water always has been known as a source of life, but nowadays there is not enough fresh water in the world. The global lack of fresh water is an issue that presents a dangerous problem to our future. Ironically, only a small portion of our planet's water is actually usable. Ninety-seven percent of the world's water is too salty for consumption or agricultural use. Furthermore, much of the rest is held in ice caps or other unattainable sources. This leaves approximately one percent of the global water as liquid and fresh; ninety-eight percent of which is groundwater (Bouwer, 2002).

For solving this problem different methods have been developed. One of them is desalination, converting sea water (rich in salts) into usable water, but this method is very expensive by the great use of electrical energy and the extraction process produces dangerous wastes to the environment (Cotruvo, 2010).

For that reason our project is focused on developing a biological machine capable of performing desalination, reducing costs and avoiding dangerous wastes during the process. For making this possible, E. coli needed to capture Na+ ions in saline environments to be removed from water after performing its task.

Before E. coli could be able to remove Na+ ions form water, it was needed to give it resistance to adverse conditions. This could be possible through a protein called IrrE which make E. coli resistant to saline environments as well as UV rays and temperature.

The protein NhaS (a new part), was used to give the ability to capture Na+ ions (bind and sequestering sodium ions). Also, the reporter BSMT1 opt (optimized), a protein able to react with salicylic acid and release a Wintergreen odor, was used to know if NhaS was expressed.

The final task E. coli should perform is to bind silica pearls to be able to be removed from the water after sequestering Na+ ions. In order to perform this, a fusion protein named L2+AIDA was used. L2 gives E. coli the ability to bind silica and AIDA acts as a tag for making L2 a membrane protein. With this ability E. coli could be removed from water through a biofilter made up of silica.

The complete circuit is shown in figure 1. BSMT1 opt acts as a reporter for NhaS which is regulated by UV (to have a control over the NhaS expression), and IrrE with L2+AIDA are continuously produced.

But we realized E. coli could have a genetic overload because the circuit was too big (approximately 5000 bp). Also the time we had to finish it was not enough, as well as most of the proteins we wanted to produce were putative or untested. So for a better understanding and for determine if each piece works we divided the project into four modules: capture, union, aroma and resistance, but the project is the result of their correlation. In fact our E. coli was named E. CARU (each letter by each module).

Escherichia coli Capture Aroma Resistance Union

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