A broad-spectrum mercury-resistant bacterial strain was isolated from contaminated water and was identified as Bacillus pasteurii strain DR2. It could volatilize Hg-compounds including organomercurials from its growth media. It utilized several aromatic compounds as a sole source of carbon. The bacterial strain eliminated HgCl2 from sterile river water and the presence of benzene, toluene, naphthalene and nitrobenzene at 1 mM concentration in the system increased the rate of mercury volatilization, the volatilization rate being highest with benzene. When 1.7 × 107 cells of this bacterial strain were added per ml of non-sterile water the bacterial strain volatilized more than 90 percent of mercury from mercuric chloride and organo-mercurials like PMA, thiomersol and methoxy ethyl mercuric chloride (MEMO). In the absence of this bacterial strain the volatilization of PMA and MEMO due to the presence of other Hg-resistant organisms in non-sterile polluted water ranged between 20-25 percent and of HgCl2 was about 40 percent. However, in the presence of B. pasteurii DR2 volatilization of these Hg-compounds from non-sterile water increased by 20-40 percent. In the presence of 1 mM benzene the rate of mercury volatilization was even higher. In all the cases the rate of volatilization was higher in the first seven days than in the next seven days.
ASJC Scopus subject areas
- Environmental Science(all)