Unraveling Cellular Controls on the Diversity of Mn Oxides Formed By Fungi
EMSL Project ID
36191
Abstract
Mn(III/IV) oxides are potent scavengers and oxidants of numerous nutrients and contaminants within the environment. The oxidation and sorption capacity of Mn oxide phases, however, is highly dependent upon their size, composition, and structure. The formation of Mn oxides is catalyzed by a diverse group of bacteria and fungi, which occurs via a number of direct (enzymatic) and indirect (metabolite) Mn(II) oxidative pathways. Fungi, in particular, have a number of oxidative pathways associated with different cellular structures (e.g., spores, hyphae) and growth stages. Very little is known, however, about either the oxidation processes utilized by fungi or the structures and reactivity of the resulting mineral products. We recently isolated and identified 13 phylogenetically distinct species of Mn(II)-oxidizing fungi from an industrially impacted freshwater pond and several acid mine drainage treatment systems. These organisms provide an ideal opportunity to define the diversity (in terms of structure, size, and speciation) of biogenic Mn oxides formed as a function of species and growth state. We are currently investigating the bulk composition, degree of site vacancies, and stacking order of the Mn oxide phases using X-ray absorption spectroscopy (XAS). Here we propose to couple the XAS results with high-resolution transmission electron microscopy (TEM) and selected area electron diffraction (SAED) for a spatially-resolved examination of the size, morphology, and structure of precipitates with respect to species and location (e.g., associated with hyphae, spores, or fruiting-bodies). Together, this information will reveal how cellular relationships impact the diversity of Mn oxide species and structures associated with fungi, which will ultimately illustrate the impact that fungi have on the reactivity of surface environments. We believe that this research is time-sensitive due to an increased interest in fungal biooxides in the scientific community and thus we request rapid access to EMSL's high resolution and Cryo-TEM for 40-80 hours to test the capability of this approach to interrogate cellular-precipitate interactions within solid substrate-associated fungal populations.
Project Details
Project type
Limited Scope
Start Date
2009-06-23
End Date
2009-08-23
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members