Grantee Research Project Results
1999 Progress Report: Biosurfactant Specificity and Influence on Microbial Degradation of Hydrocarbons by Microbial Consortia in the Field
EPA Grant Number: R827132Title: Biosurfactant Specificity and Influence on Microbial Degradation of Hydrocarbons by Microbial Consortia in the Field
Investigators: Shreve, Gina S. , Finnerty, William
Institution: Wayne State University
EPA Project Officer: Aja, Hayley
Project Period: September 1, 1998 through August 31, 2001
Project Period Covered by this Report: September 1, 1998 through August 31, 1999
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
Objective:
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 research objectives are to: (1) 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) elucidate the influence of pollutant mixtures on the effectiveness of pure and mixed biosurfactant micelles upon solubilization of hydrocarbons; (3) assess hydrocarbon solubilization on the microbial degradation of target pollutants; and (4) conduct field studies to determine the role and influence of biosurfactants in the remediation of polluted target sites.Progress Summary:
The research objectives addressed to date include: (1) examining the basis of the hydrocarbon specificity of biosurfactants based on structural and chemical properties of the biosurfactants; and (2) determining the influence of contaminant mixtures on the effectiveness of pure and mixed micelle preparations of microbial biosurfactants for solubilization of specific classes of hydrocarbons. The properties of three biosurfactants currently are under investigation for a number of contaminants that are present or structurally similar to those present in the contaminated soils from the field site. Two biosurfactants under investigation, mannosyl ester 3-hydroxy decanoic acid biosurfactant (Dyna 270) and Dyna 200, are provided by Dynazyme Incorporated. A mixture of rhamnolipids R1 and R3 also is being used in these studies. Dyna 270 and the rhamnolipids have been characterized with respect to their solubilization, interfacial tension, and micelle structural properties against target hydrocarbons from various hydrocarbon classes, including: straight chain alkanes, branched alkanes, polyaromatic hydrocarbons, monoaromatic hydrocarbons, and a light weight petroleum mixture. Various other physical-chemical properties such as the pH optimal and the most effective alkane carbon number (EACN) also were determined. The pH optimas are 5.0 for Dyna 270, 11.0 for Dyna 200, and 6.8 for rhamnolipid. The EACN for Dyna 270 is 6, the EACN for Dyna 200 is 5, and the EACN determined for rhamnolipid is dodecane.
Rhamnolipid and Dyna 270 have been evaluated with respect to their physical properties and their ability to solubilize several classes of hydrocarbons. Both biosurfactants were similar in demonstrating the ability to solubilize alkane hydrocarbons, branched alkane hydrocarbons, and monoaromatic hydrocarbons in order of decreasing effectiveness. Their effectiveness currently is under investigation for polyaromatic and chlorinated hydrocarbons as well as mixtures of the target hydrocarbons of each structural class. While the surfactants show similar packing properties at the interface, as represented by similar area per surfactant monomer head group, Dyna 270 consistently reduces the interfacial tension to a greater extent. The critical micelle concentration determined for Dyna 270 also is much lower than that of the rhamnolipid R1 and R3 mixture. This results in a much higher measured solubilization of the target hydrocarbon on a milligram of hydrocarbon solubilized per milligram of biosurfactant basis. Hydrocarbon mixture results currently are being examined to determine if these observed trends continue for complex mixtures of hydrocarbons.
Future Activities:
Results of this research will be presented at the Annual Progress Meeting for the Joint Program on Bioremediation in Chicago, IL, in November 1999.
Approximately four manuscripts are in preparation for submission to peer-reviewed scientific journals within the next academic year. One example is a manuscript entitled "Comparison of interfacial properties of two biosurfactants in varying structural classes of hydrocarbon/water systems," which is in preparation for submission to the Journal of Physical Chemistry.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 8 publications | 6 publications in selected types | All 6 journal articles |
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Sekelsky AM, Shreve GS. Kinetic model of biosurfactant enhanced hexadecane biodegradation by Pseudomonas aeruginosa. Biotechnology and Bioengineering 1999;63(4):401-409. |
R827132 (1999) R827132 (2000) R827132 (2001) R827132 (Final) |
not available |
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, Ecosystem Protection/Environmental Exposure & Risk, Waste, Toxics, Remediation, chemical mixtures, Ecology, HAPS, Environmental Chemistry, Bioavailability, Bioremediation, biosurfactant specifity, hydrocarbon degrading, kinetic studies, microbial degradation, pollutant mixtures, hydrocarbon, soil characterization, NAPL, polychlorinated biphenyls, biodegradation, fate and transport, chemical transport, NAPLs, micelle solutionsProgress and Final Reports:
Original AbstractThe 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.