Premium
Toxicity of lead in aqueous medium to Desulfovibrio desulfuricans G20
Author(s) -
Sani Rajesh K.,
Peyton Brent M.,
Jandhyala Malathi
Publication year - 2003
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620220203
Subject(s) - toxicity , chemistry , bacterial growth , metal toxicity , nuclear chemistry , desulfovibrio , metal , bacteria , sulfate , environmental chemistry , biology , organic chemistry , genetics
The toxicity of Pb(II) to sulfate‐reducing bacteria (SRB) was studied using Desulfovibrio desulfuricans G20 in a medium specifically designed to assess metal toxicity. The effects of Pb(II) toxicity were observed in terms of longer lag times, lower specific growth rates, and in some cases no measurable growth. With an increase in medium pH from 6 to 8, Pb(II) toxicity decreased. At all pH values, in the presence of Pb(II) concentrations ranging from 3 to 15 μM, specific growth rates decreased and lag times increased. The minimum inhibiting concentration (MIC) of Pb(II) causing a complete inhibition in growth at pH 6 was 10 μM, as compared to 15 μM at pH 7.2 and 8. These MIC values are 40 times lower than previously reported for SRB. Results also show that with increases in initial cell protein concentration (inoculum size), soluble Pb(II) removal rates increased and the degree to which Pb(II) caused increased lag times was reduced. In the presence of Pb(II), in all cases in which D. desulfuricans grew (even after a 312‐h lag time), the final cell protein concentration was equivalent to that of the Pb‐free control. Live/dead staining, based on membrane integrity, indicated that while Pb(II) inhibited growth, Pb(II) did not cause a loss of D. desulfuricans membrane integrity.