Diversity of Aurum bioreduction by Rhodobacter capsulatus

An environmentally friendly method using Rhodobacter capsulatus is proposed to deposit Aurum nanoparticles. Experiments of Au (III) bioreduction were conducted. There were three kinds of locations found of deposited Aurum nanoparticles, outside, inside and on the plasma membrane of the cell, which showed the diversified ability of R. capsulatus to reduce heavy metal. The mechanism for each of them had been discussed. The methods by which R. capsulatus reduced heavy metal could be more diverse than those of other microbes reported before. The capping agent was also found to stabilize the reduced Aurum in supernate. In conclusion PNSB has the powerful and diversified ability of high valent Aurum reduction. (C) 2008 Elsevier B.V. All rights reserved.