The properties of heavy metal reduction by sulfate-reducing bacteria,Citrobacter murliniae SbR-43

摘要

Sulfate-reducing bacteria (SRB), such as　Desulfovibrio , produce hydrogen sulfi de by reducing　sulfate in an anaerobic environment. Citrobacter murliniae SbR-43 , isolated from the surface soil in　Fukui Prefecture as an antimony-resistant bacteria, also has sulfate-reduction ability. In this study,a variety of heavy metals—Fe3+, Co2+, Cu2+, Zn2+, and Cd2+—containing cultivation medium wereprecipitated as sulfi de compounds with the growth of Citrobacter murliniae SbR-43 . The evolution　of the amount of H2S gas produced by Citrobacter murliniae SbR-43 is very high, and heavy metals　such as Fe3+, Zn2+, and Cd2+ precipitated more than did E. coli . Resting cells of Citrobacter murliniae　SbR-43 were coated with gold when incubated in an AuCl4- aqueous solution, and the morphologicalobservation of bacteria cells by SEM was easily possible without tedious conventional pretreatment,such as osmium staining.