Misha Mehta

E-mail: mehta058@umn.edu

Year entered: 2007

Thesis Advisor: Daniel Bond

Degrees received:
B.S., Microbiology, University of Bombay, India, 2001
M.S., Microbiology, University of Bombay, India, 2003
M.S., Molecular Biology, San Diego State University, San Diego, CA, 2007

Honors and Awards:

• 3M Science & Technology Fellowship, 2007-2010
• Microbial Diversity Summer Course, MBL, 2008, Woods Hole MA
• Lola Ellis Robertson Scholarship 2008 (for MBL)
• ASM Travel Fellowship 2009

Thesis research:

Dissimilatory metal-reducing bacteria can couple oxidation of a carbon source with the respiratory electron transport system to use various terminal electron acceptors. For example, Geothrix fermentans, a group 8 Acidobacteria can couple oxidation of acetate with the reduction of Fe(III) oxide minerals. The most abundant form of Fe in the environment is insoluble Fe(III) oxide. Therefore, for organisms to respire to extracellular insoluble Fe(III), cells must have a way to link electron transport components to their outer membrane, that may then directly or indirectly interact with the extracellular Fe(III) oxide. There are three possible mechanisms by which these microorganisms can respire on Fe(III) oxides. One mechanism of electron transfer is direct contact between the microorganism and the Fe(III) oxide particle. A second mechanism is through a redox active mediator/shuttle-like molecule that can carry electrons from the cell surface to the insoluble acceptor without requiring direct contact. Lastly, the microorganism can use a chelator, that solublizes the bound Fe(III) and subsequently allows reduction of soluble form. My goal is to determine the mechanism by which Geothrix fermentans can transfer electrons and subsequently reduce metals. Another aspect of my project is to identify key genes involved in electron transfer.