HR: 17:00h
AN: B14A-05 INVITED    [Abstracts]
TI: A Thermodynamically-Based Model For Predicting Microbial Growth And Community Composition Coupled To System Geochemistry
AU: * Istok, J D
EM: Jack.Istok@orst.edu
AF: Oregon State University Jonathan ("Jack") David Istok, Department of Civil Engineering Owen 220 Oregon State University, Corvallis, Ore 97330, United States
AB: We present an approach that couples thermodynamic descriptions for microbial growth and geochemical reactions to provide quantitative predictions for the effects of substrate addition or other enviornmental perturbations on microbial community composition. A synthetic microbial community is defined as a collection of defined microbial groups; each with a growth equation derived from bioenergetic principles. The growth equations and standard-state free energy yields are appended to a thermodynamic database for geochemical reactions and the combined equations are solved simultaneously to predict coupled changes in microbial biomass, community composition, and system geochemistry. This approach, with a single set of thermodynamic parameters (one for each growth equation), was used to predict the results of laboratory and field experiments at three geochemically diverse research sites. Predicted effects of ethanol or acetate addition on radionuclide and heavy metal solubility, major ion geochemistry, mineralogy, microbial biomass and community composition were in general agreement with experimental observations although the available experimental data precluded rigorous model testing. Model simulations provide insight into the long-standing difficulty in transferring experimental results from the laboratory to the field and from one site to the next, especially if the form, concentration, or delivery of growth substrate is varied from one experiment to the next. Although originally developed for use in better understanding bioimmobilization of radionuclides and heavy metals via reductive precipitation, the modeling approach is potentially useful for exploring the coupling of microbial growth and geochemical reactions in a variety of basic and applied biotechnology research settings.
DE: 0419 Biomineralization
DE: 0448 Geomicrobiology
DE: 0466 Modeling
SC: Biogeosciences [B]
MN: 2007 Fall Meeting