Mobilization of Metals from Pristine Mineral Soil by Nitrifying and Sulfur-Oxidizing Bacteria – The Leaching Potential of Indigenous Culture Enrichments

Abstract

Indigenous chemolithotrophic nitrifying and sulfur-oxidizing culture enrichments mobilized metals from pristine mineral soil under conditions of ammonium or thiosulfate supplementation in a laboratory experiment carried out over a period of 40 days. The average mineralogical composition of the mineral soil was quartz (62%), feldspar (20%), muscovite (6%), chlorite (2%), hornblende (2%), dolomite (4%), and calcium carbonate (4%). The leaching efficiency of the nitrifying enrichment was calcium (27%), magnesium (15%), zinc (5.4%), manganese (0.6%), and cobalt (1.4%) after 40 days of incubation. In case of sulfur-oxidizing enrichment, leaching efficiency was calcium (56%), magnesium (36%), iron (0.8%), zinc (12%), manganese (2.1%), and cobalt (12%). The impact of these organisms on pristine mineral soil could be important in understanding primary colonization and the early stages of soil formation.

Keywords:

• mineral soil
• bioleaching
• nitrifiers
• sulfur-oxidizers
• metal mobilization

ACKNOWLEDGMENTS

We thank Andreas Saxer for performing mineralogical analysis. Representative nt sequences of the bacterial species identified in this study were submitted to GenBank under HM 061136-HM061148.