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Title: MOLECULAR MECHANISM OF MICROBIAL TECHNETIUM REDUCTION FINAL REPORT

Abstract

Microbial Tc(VII) reduction is an attractive alternative strategy for bioremediation of technetium-contaminated subsurface environments. Traditional ex situ remediation processes (e.g., adsorption or ion exchange) are often limited by poor extraction efficiency, inhibition by competing ions and production of large volumes of produced waste. Microbial Tc(VII) reduction provides an attractive alternative in situ remediation strategy since the reduced end-product Tc(IV) precipitates as TcO2, a highly insoluble hydrous oxide. Despite its potential benefits, the molecular mechanism of microbial Tc(VII) reduction remains poorly understood. The main goal of the proposed DOENABIR research project is to determine the molecular mechanism of microbial Tc(VII) reduction. Random mutagenesis studies in our lab have resulted in generation of a set of six Tc(VII) reduction-deficient mutants of Shewanella oneidensis. The anaerobic respiratory deficiencies of each Tc(VII) reduction-deficient mutant was determined by anaerobic growth on various combinations of three electron donors and 14 terminal electron acceptors. Results indicated that the electron transport pathways to Tc(VII), NO3 -, Mn(III) and U(VI) share common structural or regulatory components. In addition, we have recently found that wild-type Shewanella are also able to reduce Tc(IV) as electron acceptor, producing Tc(III) as an end-product. The recent genome sequencing of a variety of technetium-reducing bacteriamore » and the anticipated release of several additional genome sequences in the coming year, provides us with an unprecedented opportunity to determine the mechanism of microbial technetium reduction across species and genus lines.« less

Authors:
 [1]
  1. Georgia Tech
Publication Date:
Research Org.:
Georgia Tech Research Corp.
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Contributing Org.:
Georgia Tech
OSTI Identifier:
1077002
Report Number(s):
DOE-GEORGIA TECH RES CORP-64124
DOE Contract Number:  
FG02-05ER64124
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Microbial technetium reduction, bioremediation, technetium-contaminated subsurface environments, in situ remediation strategy, molecular mechanism

Citation Formats

DiChristina, Thomas J. MOLECULAR MECHANISM OF MICROBIAL TECHNETIUM REDUCTION FINAL REPORT. United States: N. p., 2013. Web. doi:10.2172/1077002.
DiChristina, Thomas J. MOLECULAR MECHANISM OF MICROBIAL TECHNETIUM REDUCTION FINAL REPORT. United States. doi:10.2172/1077002.
DiChristina, Thomas J. Tue . "MOLECULAR MECHANISM OF MICROBIAL TECHNETIUM REDUCTION FINAL REPORT". United States. doi:10.2172/1077002. https://www.osti.gov/servlets/purl/1077002.
@article{osti_1077002,
title = {MOLECULAR MECHANISM OF MICROBIAL TECHNETIUM REDUCTION FINAL REPORT},
author = {DiChristina, Thomas J.},
abstractNote = {Microbial Tc(VII) reduction is an attractive alternative strategy for bioremediation of technetium-contaminated subsurface environments. Traditional ex situ remediation processes (e.g., adsorption or ion exchange) are often limited by poor extraction efficiency, inhibition by competing ions and production of large volumes of produced waste. Microbial Tc(VII) reduction provides an attractive alternative in situ remediation strategy since the reduced end-product Tc(IV) precipitates as TcO2, a highly insoluble hydrous oxide. Despite its potential benefits, the molecular mechanism of microbial Tc(VII) reduction remains poorly understood. The main goal of the proposed DOENABIR research project is to determine the molecular mechanism of microbial Tc(VII) reduction. Random mutagenesis studies in our lab have resulted in generation of a set of six Tc(VII) reduction-deficient mutants of Shewanella oneidensis. The anaerobic respiratory deficiencies of each Tc(VII) reduction-deficient mutant was determined by anaerobic growth on various combinations of three electron donors and 14 terminal electron acceptors. Results indicated that the electron transport pathways to Tc(VII), NO3 -, Mn(III) and U(VI) share common structural or regulatory components. In addition, we have recently found that wild-type Shewanella are also able to reduce Tc(IV) as electron acceptor, producing Tc(III) as an end-product. The recent genome sequencing of a variety of technetium-reducing bacteria and the anticipated release of several additional genome sequences in the coming year, provides us with an unprecedented opportunity to determine the mechanism of microbial technetium reduction across species and genus lines.},
doi = {10.2172/1077002},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2013},
month = {4}
}