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Grantee Research Project Results

NCER Grantee Research Project Results

Lipid Analysis of the Response of a Microbial Community to Polycyclic Aromatic Hydrocarbons

EPA Grant Number: U915217
Title: Lipid Analysis of the Response of a Microbial Community to Polycyclic Aromatic Hydrocarbons
Investigators: Langworthy, Donald E.
Institution: Miami University - Oxford
EPA Project Officer: Boddie, Georgette
Project Period: January 1, 1997 through January 1, 1998
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Fellowship - Microbiology , Academic Fellowships , Biology/Life Sciences

Description:

Objective:

This study examines the phenotypic and genotypic responses of the Little Scioto River sedimentary microbial community to polycyclic aromatic hydrocarbon (PAH) contamination. So that we may understand how microbial communities respond and alleviate pollutant stress I am determining PAH concentration, PAH degradative potential, microbial community structure, and degradative gene frequency in sediments from both ambient and PAH contaminated sediments to understand how microbial communities respond and alleviate pollutant stress.

Approach:

Previously, it was difficult to quantify the nature of phenotypic and genotypic changes in microbial communities, but recent developments in both molecular biology and biochemical analysis of microbial communities allow for their quantitative description. These analyses also provide the tools necessary for the assessment of pollutant impact on ecosystems and the means for tracking potential degradative consortia in the environment. Central to the approach was the use of phospholipid fatty acid (PLFA) profiles to characterize the microbial community structure, and nucleic acid analysis to quantify the frequency of degradative genes. My study site is the Little Scioto River, a highly impacted, channelized, riverine system located in central Ohio, USA. This study site is a unique lotic system with stations that are similar in physical characteristics upstream and downstream from the source of contamination. These characteristics allowed for the specific analysis of PAH impact on the microbial community. To assess the response of the microbial community to elevated concentrations of PAH, I determined: (1) PAH concentration by gas chromatography/mass spectroscopy; (2) biodegradation potential by measuring 14CO2 evolution from 14C-labeled naphthalene and anthracene; (3) total microbial biomass by phospholipid phosphate analysis; (4) changes in microbial community structure by phospholipid fatty acid analysis (PLFA) analysis; and (5) changes in the frequency of degradative gene sequences by nucleic acid analysis.

Supplemental Keywords:

fellowship, lipid analysis, microbial community, polycyclic aromatic hydrocarbons, PAHs, pollutant stress, sediments, phospholipid fatty acid, PLFA, Ohio, OH, Little Scioto River.

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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