Acidithiobacillus ferrooxidans MON-1 which is highly resistant to Hg 2+ could grow in a ferrous sulfate medium (pH 2.5) with 0.1 μM p-chloromercuribenzoic acid (PCMB) with a lag time of 2 d. In contrast, A. ferrooxidans AP19-3 which is sensitive to Hg2+ did not grow in the medium. Nine strains of A. ferrooxidans, including seven strains of the American Type Culture Collection grew in the medium with a lag time ranging from 5 to 12 d. The resting cells of MON-1, which has NADPH-dependent mercuric reductase activity, could volatilize Hg0 when incubated in acidic water (pH3.0) containing 0.1 μM PCMB. However, the resting cells of AP19-3, which has a similar level of NADPH-dependent mercuric reductase activity compared with MON-1, did not volatilize Hg0 from the reaction mixture with 0.1 μM -e;e;PCMB. The activity level of the 11 strains of A. ferrooxidans to volatilize Hg0 from PCMB corresponded well with the level of growth inhibition by PCMB observed in the growth experiments. The resting cells of MON-1 volatilized Hg0 from phenylmercury acetate (PMA) and methylmercury chloride (MMC) as well as PCMB. The cytosol prepared from MON-1 could volatilize Hg0 from PCMB (0.015 nmol mg-11), PMA (0.33 nmol rag-1 h-1) and MMC (0.005 nmol mg-1 h-1) in the presence of NADPH and β-mercaptoethanol.
- Acidithiobacillus ferrooxidans
- Iron-oxidizing bacterium
- Mercuric reductase
- Organomercurial compounds
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology