Biosurfactant Specificity and Influence on Microbial Degradation of Hydrocarbons by Microbial Consortia in the Field

EPA Grant Number: R827132
Title: Biosurfactant Specificity and Influence on Microbial Degradation of Hydrocarbons by Microbial Consortia in the Field
Investigators: Shreve, Gina S.
Current Investigators: Shreve, Gina S. , Finnerty, William
Institution: Wayne State University
EPA Project Officer: Lasat, Mitch
Project Period: September 1, 1998 through August 31, 2001
Project Amount: $424,689
RFA: EPA/DOE/NSF/ONR Joint Program on Bioremediation (1998) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management


A comprehensive research program involving basic and applied field investigations is defined to establish the efficacy of various classes of biosurfactants in the remediation of soils contaminated with mixed hydrocarbon wastes. The proposed research objectives are: 1) to determine the basis for the hydrocarbon specificity of biosurfactants in terms of micelle size, micelle dielectric constant, and targeting of minimal interfacial tension values for mixed micelle solutions to mixed wastes; 2) elucidation of the influence of pollutant mixtures on the effectiveness of pure and mixed biosurfactant micelles upon solubilization of hydrocarbons; 3) the assessment of hydrocarbon solubilization on the microbial degradation of target pollutants; and 4) field studies to determine the role and influence of biosurfactants in the remediation of polluted target sites.


In-depth and detailed analyses of selected biosurfactants will be undertaken to establish useful mechanistic and kinetic models predictive of biosurfactant activities in enhancement of microbial degradation of HOCs and NAPL source reduction as well as strategies for their effective use in field applications. Surface activity, interfacial activity and micelle structure of biosurfactant preparations will be measured in the presence of mixed wastes containing polychlorinated biphenyls, chlorinated aliphatic hydrocarbons, straight chain, branched alkane and mono- and polycyclic aromatic hydrocarbons. The comparison of biosurfactant micelle size and interior dielectric constant data with hydrocarbon solubilization data will allow the determination of the relative importance of micelle size and chemical characteristics for determining the hydrocarbon solubilization specificity of the biosurfactant. Laboratory soil column studies will evaluate the effectiveness of various biosurfactants in the microscopic displacement of specific contaminants from soils contaminated with hydrocarbon mixtures. Hydrocarbon degradation experiments will indicate the presence of possible inhibitory effects in mixed micelle/mixed culture hydrocarbon degradation systems. Field studies will be conducted using exogenously added mixtures of biosurfactants. As part of these field studies the performance of the biosurfactant systems will be tested in remediation of sites contaminated with mixed fuels containing monoaromatic, linear and highly branched alkane hydrocarbons, polycyclic aromatic hydrocarbons, and chlorinated solvents. Persistence of specific hydrocarbon and PAH species in the field will be related to the defined laboratory studies. The mechanistic kinetic model for biosurfactant mediated NAPL source reduction will be further developed for the laboratory soil column studies and its applicability for describing the reduction of the NAPL phase in the field will be examined. In-situ field amendment strategies will be employed to examine the effect of the addition of targeted biosurfactant mixtures on target HOC degradation by indigenous and exogenously added microbial consortia under hypoxic and reducing conditions. Long term follow-up analysis of the site will provide information as to the effect of the proposed amendment strategies on stimulation of indigenous biosurfactant production and NAPL source reduction.

Expected Results:

This research program will provide a framework for understanding the interactions that exist between surface-active agents, contaminant mixtures and their effects on the rate and magnitude of biodegradation by microorganisms in the natural environment. The distinct benefits expected from this project are: 1) a more complete understanding of the influence of biosurfactant chemical features on hydrocarbon solubilization properties, permitting more precise predictive capability of a biosurfactant's hydrocarbon specificity and potential role in the biodegradation of subject pollutants; 2) evaluation of the effectiveness of biosurfactants in affecting contaminant partitioning in chemically heterogeneous multiphase mixtures; 3) an improved understanding and appreciation of the mechanistic and kinetic phenomena governing solubilization and microbial transformation of insoluble hydrocarbon; 4) an indication of the potential for stimulating indigenous biosurfactant production in the field; 5) an increased understanding the features controlling biosurfactant's performance in mixed waste/mixed microorganism systems as a microbial mechanism to overcome contaminant sorption and sequestration; 6) correlation of contaminant partitioning and contaminant recalcitrance in laboratory and field studies; and 7) acquisition of preliminary rate data which may be used in contaminant fate and transport models for field assessment. The inclusion of potential microbial mechanisms affecting hydrophobic contaminant partitioning and bioavailability in existing contaminant transport models will enhance the applicability of such models for decision support of risk assessment and risk management activities.

Publications and Presentations:

Publications have been submitted on this project: View all 8 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 6 journal articles for this project

Supplemental Keywords:

biosurfactant specificity, mixed waste solubilization, micelle characterization, biosurfactant mediated solubilization and biodegradation, NAPL source reduction, mechanistic kinetic model, surfactant mediated HOC transport, microbial biodegradation, RFA, Scientific Discipline, Toxics, Waste, Ecosystem Protection/Environmental Exposure & Risk, Bioavailability, Ecology, Remediation, Environmental Chemistry, HAPS, chemical mixtures, Bioremediation, fate and transport, micelle solutions, pollutant mixtures, microbial degradation, NAPL, hydrocarbon, PCBs, biodegradation, chemical transport, kinetic studies, polychlorinated biphenyls, soil characterization, biosurfactant specifity, NAPLs

Progress and Final Reports:

  • 1999 Progress Report
  • 2000 Progress Report
  • Final Report