Description
We were inspired by both Kyoto2018 and Aachen2017 iGEM teams and decided to work on water desalination using microorganisms. We found out that they reached a good point in bio-desalination but there are still some improvements could be done in the ions sequestration efficiency, the organism tolerance to salinity and chassis selection.
We are going to fulfill our project through genetic modification of “Debaryomyces hansenii” a halotolerant yeast which is within the normal flora of the sea. This yeast can tolerate NaCl up to 3M, for that it has been chosen as a model for molecular studies of NaCl tolerance.
Salts uptake process happens naturally, but we would manipulate the cells not to release the salts back to the environment, by knocking out the efflux channels, this would be toxic for the cell and may lead to cytolysis. We’ll overcome that by expressing osmoprotectants such as myo-inositol to preserve cell integrity under high salinity stress.
Another novel approach we are working on is the cell-free approach, We will be testing the metal binding proteins affinity to bind to Sodium Chloride and decrease the TDS in the water where we will use the protein itself without any microorganisms, this would allow us to avoid the obvious drawback of introducing modified microorganisms into the water.
We can further separate the yeast easily using the hardware which is a hydrocyclone that would separate both the water and the yeast according to their relative densities.
Inspiration
Over a year ago, we decided to participate in iGEM. Thus, started studying the emerging scientific field of Synthetic Biology. That was a long journey that lasted over a year.
After that, we started reading previous iGEM projects, then followed that by working on applicable ideas to solve critical problems that face our country in all different fields.
Narrowing our circle of search, after intense brainstorming and several meetings, we found out that Egypt is facing several environmental problems that drastically affect the society. We decided to work on the Environmental track.
One day while categorizing the problems, we were shocked by the news that the third largest lake in Egypt and the second most famous one "Lake Qarun" which was once a freshwater lake is turning into a huge salt basin that made it unsuitable for drinking[1]. As a result of the increasing rate of population growth, more rigorous cultivation, irrigation and other human activities, as well as the high rate of evaporation, have led to a high concentration of salts[2]. The lake is now approaching the salinity of seawater, with a ratio of around 34.5 parts per thousand, said to be growing at a rate of 0.4 parts per year[3].
This was the first inspiration that led us to work on saline water desalination.
Despite that Egypt has the longest river in the world “The Nile River”, which is the backbone of the industrial and agricultural sectors and is the primary source of drinking water for the population[4] in which it supplies 56.8 billion m³ of freshwater every year[5]. The expanding population, misuse of water resources, inefficient irrigation, and other human activities made Egypt vulnerable in water resources[4].
The UN predicts that Egypt will be approaching a state of absolute water crisis by 2025 and that the nation is already below the United Nations’ water poverty threshold[6].
“The state suffers from an annual 21 billion cubic meters gap between water consumption and production. The consumption reached 110 billion cubic meters, while Egypt currently has 60 million cubic meters annually’’ said the Minister of Water Resources and Irrigation Mohamed Abdel Atti in October 2018[7].
Our point of view also extends to cover the whole world; thinking of solving the water shortage problem as 1.6 billion people, or almost one-quarter of the world's population face economic water shortage and more than 2.1 billion people lack access to clean drinking water. As more than 97% of earth's water content is saline[8], also taking into account the fact that Egypt has both the Mediterranean and Red seas, we decided to make use of this wasted opportunity through unique desalination method (Biodesalination) and provide a new resource of water, as the existing drawbacks of conventional desalination techniques cost worth of money and use large amounts of energy as most of the desalination plants use fossil fuel, which dramatically affects the environment in a catastrophic way and contributes to the global warming problem. So, all of the above directed us to Bio-desalination.
In nature, some plants as mangrove, Spartina, and Arabidopsis thaliana are able to survive in salty environments. In addition to that, there are also some microorganisms which possess many mechanisms to tolerate salt stress using specific proteins that can handle the toxicity resulting from the presence of excess salt.
From that our idea arose to develop and reconstruct these systems, adding those specific traits adopted from the salt-tolerant plants and microorganisms to our modified organism to be able to collect the salt ions, ending up with fewer salts in the water with high efficiency.
