The Effect of In Situ Biosurfactant Production on Hydrocarbon BiodegradationEPA Grant Number: R826161
Title: The Effect of In Situ Biosurfactant Production on Hydrocarbon Biodegradation
Investigators: Strevett, Keith A. , Sabatini, David A. , Everett, Jess , Tanner, R.
Institution: University of Oklahoma
EPA Project Officer: Lasat, Mitch
Project Period: March 10, 1998 through March 9, 2001 (Extended to September 9, 2001)
Project Amount: $323,072
RFA: Exploratory Research - Environmental Engineering (1997) RFA Text | Recipients Lists
Research Category: Land and Waste Management , Engineering and Environmental Chemistry
The goal of this research is the development of a mechanistic and innovative methodology that can effectively predict and describe anaerobic and aerobic biodegradability of hydrocarbons as impacted by biosurfactants.
The proposed study derives from the fundamental hypothesis that bioavailability of hydrocarbons in mixed chemical matrices can be described based on the individual interactions occurring in the environment. These interactions may include soil-chemical, soil-microorganism, soil-biosurfactant, microorganism-biosurfactant, etc. This research effort will, therefore, set out to quantitatively determine: the biological removal of hydrocarbons in a chemical matrix (e.g., light non-aqueous phase liquid) considering both anaerobic and aerobic metabolism in the presence of biosurfactant produced in situ; assessment of abiotic surface characteristic as altered by biosurfactants examine the decrease of interfacial tension of sorbed compounds; impact of biosurfactants on chemical transport; assessment of microbial (biotic) surface characteristic as altered by biosurfactants impact of biosurfactant on contaminant transport across cellular membrane or decrease of interfacial tension, thus increase/decrease microbial attachment to a solid matrix; impact of biosurfactants on microbial migration ability of microorganism to transport with a contaminated plume; and development of a mechanistically based model to predict the effect of in situ biosurfactant production on bioavailability based on the physicochemical characteristic of the surfactant and the surface thermodynamics of the soil and indigenous microorganisms. This prediction will use traditional interfacial forces, including Lewis acid/base, van der Waals, and electrostatic forces determined via contact angle measurements and electrophoretic assays, as well as, traditional biokinetic models.
This research proposal outlines the implementation of batch experiments to determine intrinsic biodegradation coefficients in both anoxic and oxic conditions, biosurfactant sorption kinetics, apparent biodegradation kinetic coefficients in the presence of biosurfactant produced in situ, biosurfactant-hydrocarbon interaction, biosurfactant-soil matrix interactions, and biosurfactant-chemical matrix interactions. In addition, column experiments are used to evaluate batch experiment parameters in a flow field to promote further evaluation and scale-up of the fundamentally-based model. The experimentally determined results will be compared with theoretical predictions using independently determined surface thermodynamic and biokinetics parameters.
The expected results from this research will produce an advanced methodology to describe and predict bioavailability impact on bioremediation strategies. This methodology integrates physicochemical and biogeochemical processes with biophysical chemistry to evaluate migrating groundwater contamination scenarios.