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Hexavalent-chromium reduction by a chromate-resistant Bacillus sp. strain
J Campos1, M Martinez-Pacheco, C Cervantes
1Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana, Morelia, Mexico.
Antonie Van Leeuwenhoek
|October 1, 1995
Summary
Bacillus strain QC1-2 efficiently reduces toxic hexavalent chromium [Cr(VI)] to less toxic trivalent chromium [Cr(III)] under aerobic and anaerobic conditions. This chromium reduction is mediated by a soluble, NADH-dependent enzyme, offering potential for bioremediation applications.
Area of Science:
- Environmental Microbiology
- Bioremediation
- Toxicology
Background:
- Hexavalent chromium [Cr(VI)] is a toxic heavy metal pollutant.
- Bioremediation using microorganisms is a promising strategy for chromium removal.
- Identifying efficient microbial strains for Cr(VI) reduction is crucial.
Purpose of the Study:
- To isolate and characterize a bacterial strain with high hexavalent chromium [Cr(VI)] tolerance and reduction capabilities.
- To investigate the optimal conditions and enzymatic mechanisms underlying Cr(VI) reduction by the selected strain.
Main Methods:
- Isolation and screening of chromium-tolerant bacteria from a polluted site.
- Assessing Cr(VI) reduction under aerobic and anaerobic conditions.
- Enzyme assays using permeabilized cells and cell extracts to identify the reductase activity.
Main Results:
- Bacillus strain QC1-2 demonstrated significant tolerance and rapid reduction of Cr(VI) to Cr(III).
- Cr(VI) reduction occurred effectively in both aerobic and anaerobic environments.
- The reduction process was dependent on glucose and mediated by a soluble NADH-dependent enzyme.
Conclusions:
- Bacillus strain QC1-2 is a potent agent for Cr(VI) bioremediation.
- The identified NADH-dependent reductase offers a target for biotechnological applications in chromium detoxification.