Team:Hunter-NYC

Project Description

One of the most valuable and finite natural resources on the planet is clean water. As the global temperature increases, fresh water supplies stored in glaciers and ice caps are melting. Climate change induced droughts in certain areas are causing lakes and rivers – bodies of water civilizations have depended on for millennia – to dry up. Industrial processes use fresh water as a coolant and deplete supplies of fresh water, or they result in water contamination by toxic metal ions when industrial waste is dumped or not stored properly. Because of the great number of threats to our planet’s drinking water supply, we, the Hunter College NYC iGEM team, have set out to engineer a biologically produced filtering molecule that would safely remove metal ions from contaminated water supplies in a single step, that is without the necessity to retrieve this filtering molecule from the water supply at a later point.

	We have designed a fusion protein consisting of a domain that binds strongly to zinc, cobalt and cadmium and the C-terminus of the Pseudomonas sp. lipase (PML), which acts as a secretion tag for E. coli cells containing the lipBCD genes from S. marcescens.  We would like our system to be as sustainable and low-cost as possible so that it, or an improved version of it, would be practical and applicable in developing nations where contaminated water supplies are especially problematic.  We hope that using a protein secretion system will help us achieve that goal by providing us with an easy, low energy means to purify the metal filtering fusion protein.  In this scheme, the same population of E. coli can be used to produce our protein multiple times since the protein would accumulate in the growth media and not within the cells, in which case we would need to lyse the E. coli in order to prepare each filter. 

One of the most important features we have incorporated into our design is the ability of our filtering protein to easily bind a solid surface. By doing so, we can expose our protein to contaminated water without simply pouring it in. Thus, we can accomplish purification but we never have to go through a second process in which we would have to remove a dissolved metal-chelating molecule from a large body of water.

In short, we hope to engineer bacteria to secrete an easily usable and easily retrievable protein that favorably binds toxic heavy metal ions with the purpose of cleaning our planet’s precious supply of fresh water.