20.109(F12) Pre-Proposal: Mercury Decontamination of Water Using Bacterial Aggregation

Investigators

• Andrea Nickerson
• Martina de Geus
• Saad Shoukat
• TR
• Purple

Title of Proposed Project

20.109(F12) Pre-Proposal: Mercury Decontamination of Water Using Bacterial Aggregation

Project Summary

In July of 2010, during the first UN conference for a global mercury treaty it was recorded that mercury levels in hair samples of delegates from developing countries on average was twice as high as average levels in hair samples of delegates from developed nations. While the dangers of high mercury water levels in developing nations around the world have been identified, methods for purifying contaminated water are a step behind from where they need to be. The proposed research will address efficient ways of isolating and extracting mercury from contaminated water in a biologically feasible manner.

Introduction

Coal is one of the largest energy sources not only in the United States, but also internationally. Coal contains mercury which is released into the atmosphere as it is burned. This gaseous form then condenses and falls to the earth with rain and snow, thereby polluting not only soil but also water systems. Mercury poisoning has become an increasing cause for concern. Mercury exposure from fish consumption poses a serious threat to human health, particularly to the central nervous and cardiovascular systems. It is particularly harmful to early brain development.

Our idea

While many technologies exists to monitor and decrease mercury pollution, most are either not cost-effective or require too much energy, making them poor options for third world countries. Currently, the two most promising methods of purification, the ZeeWeed 500 and Blue Pro, rely on large scale systems which pass water through filters that are used to extract mercury. Though these systems achieve unparalleled efficiency, their complexity takes away from potential wide scale usage. We look to combine not only cost efficiency but also minimal energy dependence into our idea to give an efficient and widely accessible means to large scale mercury purification.

From the literature it appears that few if any large-scale projects take advantage of bioremediation to reduce mercury contamination. Bacteria that specifically binds mercury have been constructed, and we want to manipulate the genes so it can be used for a large-scale application. We hope to achieve this by utilizing mechanisms found in quorum sensing and biofilm creation to allow the bacterial cells to be easily collected from the water. This will require biologically engineering a pathway that responds to the bound mercury at the cell membrane by initiating quorum sensing to aggregate the other mercury-bound bacteria. This method will allow the bacteria to form visible clumps that can be easily removed from a lake or pond without the use of expensive filtration systems.

A sketch

References

Bae Et Al. "Enhanced Mercury Biosorption by Bacterial Cells with Surface-Displayed MerR." Applied Environmental Microbiology. June 2003. Web. 29 Nov. 2012. <http://aem.asm.org/content/69/6/3176.full>.

Jenssen Et Al. "Dietary Mercury Exposure in a Population with a Wide Range of Fish Consumption - Self-capture of Fish and Regional Differences Are Important Determinants of Mercury in Blood." National Center for Biotechnology Information. U.S. National Library of Medicine, 13 Oct. 2012. Web. 29 Nov. 2012. <http://www.ncbi.nlm.nih.gov/pubmed/23069934>.

Knapp, Ron. "Coal Report - Executive Summary." Coal Report - Executive Summary. World Coal Institute, n.d. Web. 29 Nov. 2012. <http://www.unep.fr/scp/csd/wssd/contributions/sector_reports/sectors/coal/coal_sum.htm>.

Li, Yung-Hua, and Xiaolin Tian. "Quorum Sensing and Bacterial Social Interactions in Biofilms." National Center for Biotechnology Information. U.S. National Library of Medicine, 23 Feb. 2012. Web. 29 Nov. 2012. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3376616/>.

"Mercury in Fish: Health Advice on Eating Fish." Mercury in Fish: Health Advice on Eating Fish. Department of Health and Human Services, 2 May 2012. Web. 29 Nov. 2012. <http://epi.publichealth.nc.gov/fish/mercuryhealthfacts.html>.

Wang Et Al. "Modifying Fe(3)O(4) Microspheres with Rhodamine Hydrazide for Selective Detection and Removal of Hg(2+) Ion in Water." National Center for Biotechnology Information. U.S. National Library of Medicine, 2 Nov. 2012. Web. 29 Nov. 2012. <http://www.ncbi.nlm.nih.gov/pubmed/23177242>.