Structure, Function, and Stability of Engineered Microbial Communities

EPA Grant Number: FP916408
Title: Structure, Function, and Stability of Engineered Microbial Communities
Investigators: Gentile, Margaret E.
Institution: Stanford University
EPA Project Officer: Packard, Benjamin H
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $107,688
RFA: STAR Graduate Fellowships (2004) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Environmental , Safer Chemicals


Engineered microbial communities are used to solve a variety of environmental problems ranging from treatment of industrial and municipal wastewaters to the remediation of contaminated sites. These biological treatment systems, however, vary in function (the ability to remove contaminants) and stability (the maintenance of function over long time scales and in response to disturbances in operating conditions). Differences in microbial community structure and dynamics may contribute to this apparent yet unexplained variation among systems. The objective of this research is to elucidate basic relationships between function, stability, and microbial community structure and dynamics. Ultimately, this understanding will contribute to improving design and operation strategies, yielding more efficient and stable treatment systems.


In the laboratory, denitrification will be studied as a model process because of its widespread importance in engineering applications, including nitrogen removal from wastewater and bioremediation of polluted groundwater. The structure of a model denitrifying community will be simplified by a dilution series, allowing for the evaluation of populations’ contributions to overall function and stability as they are removed in the dilutions. The effect of dilution on community structure and subsequent community dynamics will be examined through a combination of molecular techniques including clone libraries and terminal restriction fragment length polymorphism (T-RFLP) of the small subunit rDNA gene and the denitrification functional genes. Function and stability of the communities at each dilution will be assessed by monitoring concentrations of nitrate and the denitrification intermediates in the effluent of continuous reactors during constant operating conditions and in response to disturbances.

Supplemental Keywords:

fellowship, wastewater treatment, engineered microbial communities, denitrification, bioremediation, groundwater treatment, biological treatment systems, continuous reactors, terminal restriction fragment length polymorphism, T-RFLP,, Scientific Discipline, Water, TREATMENT/CONTROL, Environmental Chemistry, Environmental Microbiology, Engineering, Chemistry, & Physics, Environmental Engineering, Water Pollution Control, wastewater treatment, microbial degradation, groundwater remediation, remediation, groundwater contamination, aqueous waste

Relevant Websites:

2004 STAR Graduate Fellowship Conference Poster (PDF, 1p., 163KB, about PDF)

Progress and Final Reports:

  • 2004
  • 2005
  • Final