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A PMA degrading constitutive organomercurial lyase in a broad-spectrum mercury resistant Bacillus pasteurii strain
1Department of Biochemistry, University College of Science, Calcutta, India.
Abstract:
A broad-spectrum Hg-resistant strain of B. pasteurii DR2 utilized phenylmercuric acetate (PMA) as sole source of carbon. This bacterial strain contained a constitutive organomercurial lyase which specifically degraded PMA but not other organo-mercurials. This PMA-lyase activity was also stimulated to different extents when this bacterial strain was grown in presence of different organic compounds as sole source of carbon.
Insights
A mercury-resistant bacterial strain, Bacillus pasteurii DR2, can use phenylmercuric acetate (PMA) as its carbon source. It possesses a specific enzyme that degrades PMA, with activity influenced by other carbon sources.
Area of Science:
- Environmental microbiology
- Bioremediation
- Enzymology
Background:
- Mercury resistance in bacteria is a significant environmental concern.
- Organomercurial compounds pose toxic risks.
- Understanding microbial degradation pathways is crucial for bioremediation.
Purpose of the Study:
- To investigate the utilization of phenylmercuric acetate (PMA) by a mercury-resistant bacterial strain.
- To characterize the enzyme responsible for PMA degradation.
- To explore factors influencing the activity of this enzyme.
Main Methods:
- Isolation and identification of a mercury-resistant bacterial strain (Bacillus pasteurii DR2).
- Cultivation of the bacteria using PMA as the sole carbon source.
- Enzyme assays to determine PMA-lyase activity and substrate specificity.
- Growth studies with different organic compounds to assess enzyme activity modulation.
Main Results:
- Bacillus pasteurii DR2 effectively utilizes PMA as its sole carbon and energy source.
- The strain possesses a constitutive organomercurial lyase enzyme.
- This enzyme specifically degrades PMA, showing no activity against other tested organomercurials.
- PMA-lyase activity is enhanced when the bacteria are grown in the presence of various organic compounds.
Conclusions:
- Bacillus pasteurii DR2 demonstrates a unique metabolic capability for degrading PMA.
- The constitutive and specific PMA-lyase offers potential for targeted bioremediation of PMA contamination.
- Environmental factors, such as the presence of other organic compounds, can modulate the efficiency of mercury detoxification.