Mn Oxide Biogenesis and Metal Sequestration in the Presence of Co (II) and Cu (II) By Bacillus SG-1 Bacterial Spores

Mn oxides play an important role in degrading contaminants and cycling nutrients in soils and natural waters. The process in which Mn (II) oxidizes to form MnO, is slow; however, Bacillus SG-1 bacterial spores can catalyze the process and allow it to proceed up to five orders of magnitude faster. This experiment explored the affects of co-ion metal concentrations on Biogenic Mn oxide production and their ability to sequester metal cations. Spore solutions were prepared with different ratios of Metal (II): Mn (II) added over a three-week period; this was done separately for Co (II) and Cu (II). The copper solutions were analyzed with ICP/AES to check for the amount of copper and manganese left in solution after biogenic MnO, production. ICP/AES was used to analyze the ratio of Co: Mn in spores where Co was the co-ion metal. Observations showed very little dissolved Cu and Mn exist in solutions with low copper concentrations, but a large amount of Cu and Mn were left in solutions where higher Cu concentrations were used. This shows that high Cu concentration inhibits biogenic Mn oxide production and Cu sequestration. For the experiments with Co as the co-ion metal, it was observed that themore » ratio of Co: Mn in the spores is relatively similar to the ratios added; however, an exception to this rule was experiments where high concentrations of Co were used. The inconsistency in Co: Mn ratios at high Co concentrations showed that high Co concentrations also inhibit biogenic Mn oxide production.« less