TY - JOUR
T1 - Fungal oxidative dissolution of the Mn(II)-bearing mineral rhodochrosite and the role of metabolites in manganese oxide formation
AU - Tang, Yuanzhi
AU - Zeiner, Carolyn A.
AU - Santelli, Cara M.
AU - Hansel, Colleen M.
PY - 2013/4
Y1 - 2013/4
N2 - Microbially mediated oxidation of Mn(II) to Mn(III/IV) oxides influences the cycling of metals and remineralization of carbon. Despite the prevalence of Mn(II)-bearing minerals in nature, little is known regarding the ability of microbes to oxidize mineral-hosted Mn(II). Here, we explored oxidation of the Mn(II)-bearing mineral rhodochrosite (MnCO3) and characteristics of ensuing Mn oxides by six Mn(II)-oxidizing Ascomycete fungi. All fungal species substantially enhanced rhodochrosite dissolution and surface modification. Mineral-hosted Mn(II) was oxidized resulting in formation of Mn(III/IV) oxides that were all similar to δ-MnO2 but varied in morphology and distribution in relation to cellular structures and the MnCO3 surface. For four fungi, Mn(II) oxidation occurred along hyphae, likely mediated by cell wall-associated proteins. For two species, Mn(II) oxidation occurred via reaction with fungal-derived superoxide produced at hyphal tips. This pathway ultimately resulted in structurally unique Mn oxide clusters formed at substantial distances from any cellular structure. Taken together, findings for these two fungi strongly point to a role for fungal-derived organic molecules in Mn(III) complexation and Mn oxide templation. Overall, this study illustrates the importance of fungi in rhodochrosite dissolution, extends the relevance of biogenic superoxide-based Mn(II) oxidation and highlights the potential role of mycogenic exudates in directing mineral precipitation.
AB - Microbially mediated oxidation of Mn(II) to Mn(III/IV) oxides influences the cycling of metals and remineralization of carbon. Despite the prevalence of Mn(II)-bearing minerals in nature, little is known regarding the ability of microbes to oxidize mineral-hosted Mn(II). Here, we explored oxidation of the Mn(II)-bearing mineral rhodochrosite (MnCO3) and characteristics of ensuing Mn oxides by six Mn(II)-oxidizing Ascomycete fungi. All fungal species substantially enhanced rhodochrosite dissolution and surface modification. Mineral-hosted Mn(II) was oxidized resulting in formation of Mn(III/IV) oxides that were all similar to δ-MnO2 but varied in morphology and distribution in relation to cellular structures and the MnCO3 surface. For four fungi, Mn(II) oxidation occurred along hyphae, likely mediated by cell wall-associated proteins. For two species, Mn(II) oxidation occurred via reaction with fungal-derived superoxide produced at hyphal tips. This pathway ultimately resulted in structurally unique Mn oxide clusters formed at substantial distances from any cellular structure. Taken together, findings for these two fungi strongly point to a role for fungal-derived organic molecules in Mn(III) complexation and Mn oxide templation. Overall, this study illustrates the importance of fungi in rhodochrosite dissolution, extends the relevance of biogenic superoxide-based Mn(II) oxidation and highlights the potential role of mycogenic exudates in directing mineral precipitation.
UR - http://www.scopus.com/inward/record.url?scp=84875897413&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84875897413&partnerID=8YFLogxK
U2 - 10.1111/1462-2920.12029
DO - 10.1111/1462-2920.12029
M3 - Article
C2 - 23157705
AN - SCOPUS:84875897413
SN - 1462-2912
VL - 15
SP - 1063
EP - 1077
JO - Environmental microbiology
JF - Environmental microbiology
IS - 4
ER -