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Cornell iGEM

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Project I want chocolate

Heavy metal pollution in water is one of the most significant public health risks around the world. Pollutants, including lead, mercury, and nickel, can enter water supplies through a number of methods, including improper disposal of waste, industrial manufacturing, and mining. When solubilized, these metals have the ability to cause environmental and health problems, such as acute toxicity at high concentrations and carcinogenicity with long-term exposure even at low concentrations. Methods exist to remove heavy metals from water supplies, but these methods create other hazardous wastes and are much more effective in waters with high concentrations of metals. Due to the high affinity of binding proteins, a biological based filtration system can be more effective at treating water contaminated with lower concentrations of heavy metals without generating large volumes of toxic waste.

Our team plans to combat heavy metal pollution by improving existing biological filtration methods and developing a novel system for lead remediation. To this end, we are engineering bacterial strains that will simultaneously express heavy metal transport proteins and metallothioneins, a class of low-molecular-weight proteins with high binding affinities for various heavy metals. The heavy metal transport proteins are specific to certain metals and will cause rapid intake of these ions. The metallothioneins will then bind to these ions intracellularly and permanently sequester them. After filtration, the respective heavy metals can be isolated by recollecting the cells from the filter. In addition to developing these strains, our dry lab team plans to develop a hollow fiber reactor with several chambers, each designed to collect a specific metal. We then plan to test the efficacy of different combinations of filters in series using samples of contaminated waters near a local contaminated site.

Previously, research groups have developed such filtration systems for some of the most harmful heavy metals. One of our faculty advisors at Cornell, Dr. David Wilson, has developed such systems for mercury and nickel. We plan to work to improve the efficiency and lifespan of these filtration systems. Additionally, we will be developing a novel sequestration system for lead by utilizing a putative lead transport protein from Nicotiana tabacum.