A preliminary characterization of mercury uptake by the sulfate-reducing bacteria Desulfovibrio desulfuricans

Authors

Amaury Pedro Betancourt III, Florida International University

Document Type

Thesis

Degree

Master of Science (MS)

Major/Program

Environmental Engineering

First Advisor's Name

Hector R. Fuentes

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Georgio Tachiev

Third Advisor's Name

Shonali Laha

Fourth Advisor's Name

Yelena Katsenovich

Date of Defense

3-2-2011

Abstract

The focus of this research is to determine if a relationship exists between the stability constant and the initial uptake rate of a mercury species by bacteria. Cultures of the sulfate-reducing bacteria (SRB) strain Desulfovibrio desulfuricans G20 were washed with a bicarbonate buffer solution containing either lactate and sulfate or pyruvate and fumarate. The washed cell solutions were then spiked with either mercury bound to natural organic matter (Hg-NOM) or neutral mercury chloride (HgCl₂), followed by sampling over time to provide kinetic data. Despite the significantly different stability constants for Hg-NOM and HgCl₂, the calculated initial rate constants for mercury uptake for these two types of complexes appeared to be comparable. Uptake of mercury sulfide species was inconclusive due to possible formation of cinnabar. A simple model that is based on assumptions of passive diffusion and facilitated uptake of mercury by bacteria was evaluated for its potential to simulate the uptake. The model results only agreed with experimental data for HgCl₂ uptake.

Identifier

FI14051132

Recommended Citation

Betancourt, Amaury Pedro III, "A preliminary characterization of mercury uptake by the sulfate-reducing bacteria Desulfovibrio desulfuricans" (2011). FIU Electronic Theses and Dissertations. 1649.
https://digitalcommons.fiu.edu/etd/1649