Abstract
The influence of temperature (5, 10, 22 and 30 C) on the long-term (30 days) sorption of Mn2+ by viable
Shewanella putrefaciens was studied by FTIR and EXAFS. The additional Mn-removal capacity of these
bacteria was found to result from the surface precipitation of Mn-containing inorganic phases. The
chemical composition of the Mn-containing precipitates is temperature and contact-time dependent.
Mn(II) phosphate and Mn(II) carbonate were the two major precipitates formed in 1000 mL batches at 10,
22 and 30 C. The ratio of Mn(II) phosphate to Mn(II) carbonate was a function of the contact time. After
30 days, MnCO3 was the dominant phase in the precipitates at 10, 22 and 30 C; however, MnCO3 did
not form at 5 C. Mn(II) phosphate was the only precipitate formed at 5 C over 30 days. The
biosynthesis of Extracellular Polymeric Substances (EPS) was much greater at the lowest temperature
(5 C); however, these polymeric sugars did not contribute to the additional removal of Mn(II) under the
experimental conditions. This work is one of the first reports demonstrating the ability of microbes to
bioprecipitate manganese phosphate and manganese carbonate. Because of the focus on interfacial
processes, this is the first report showing a molecular-level mechanism for manganese carbonate
formation (in contrast to the traditionally studied aged minerals).
Shewanella putrefaciens was studied by FTIR and EXAFS. The additional Mn-removal capacity of these
bacteria was found to result from the surface precipitation of Mn-containing inorganic phases. The
chemical composition of the Mn-containing precipitates is temperature and contact-time dependent.
Mn(II) phosphate and Mn(II) carbonate were the two major precipitates formed in 1000 mL batches at 10,
22 and 30 C. The ratio of Mn(II) phosphate to Mn(II) carbonate was a function of the contact time. After
30 days, MnCO3 was the dominant phase in the precipitates at 10, 22 and 30 C; however, MnCO3 did
not form at 5 C. Mn(II) phosphate was the only precipitate formed at 5 C over 30 days. The
biosynthesis of Extracellular Polymeric Substances (EPS) was much greater at the lowest temperature
(5 C); however, these polymeric sugars did not contribute to the additional removal of Mn(II) under the
experimental conditions. This work is one of the first reports demonstrating the ability of microbes to
bioprecipitate manganese phosphate and manganese carbonate. Because of the focus on interfacial
processes, this is the first report showing a molecular-level mechanism for manganese carbonate
formation (in contrast to the traditionally studied aged minerals).
Original language | English |
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Pages (from-to) | 780-790 |
Journal | Environmental Science. Processes & Impacts |
Volume | 17 |
Issue number | 4 |
Early online date | 13 Feb 2015 |
DOIs | |
Publication status | Published - Apr 2015 |