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Casey Ching

A Study on Rhamnolipid-90 Micellization

Department: Civil and Environmental Engineering
Advisor: Derick Brown

Abstract:
Surfactants – molecules with both hydrophobic and hydrophilic components – are used in numerous consumer and industrial products. The duality of surfactants reduces the surface tension of water, allowing the use of surfactants as lubricants and wetting agents. They also form aggregates, termed micelles, that enhance the solubility of hydrophobic compounds, allowing their use in consumer detergents and industrial cleaning solutions. Micelles have also been shown to enhance the bioavailability and biodegradation of environmental contaminants. Use of anthropogenic surfactants is widespread and they are found in household detergents, shampoos, personal care products, paints, pesticides, and cleaning agents. However, one important class of anthropogenic surfactants is of concern as they can persist in the environment and have a potential role as an endocrine disruptor. An attractive alternative to anthropogenic surfactants is biosurfactants, which are created by microorganisms. Biosurfactants serve the same function as surfactants, but are generally less toxic, more easily biodegradable, and more stable at extreme pH’s and temperatures. There are many aspects of biosurfactants that must be elucidated to make them competitive to anthropogenic surfactants. In this study, properties of the biosurfactant Rhamnolipid-90, formed from the bacterium Pseudomonas aeruginosa, were studied to understand its micelle formation and adsorption on the bacterial surface. This information will better our understanding of Rhamnolipid-enhanced solubilization and biodegradation of environmental contaminants and how it will interact with the environment on a microscopic scale.

About Casey Ching:
Casey Ching is a Lehigh University senior majoring in Environmental Engineering. Her interest concerning human impacts on the environment is motivated partly by her study abroad experiences in Cambodia and Costa Rica as part of Lehigh’s Global Citizenship program. As a Clare Boothe Luce Scholar, she has worked in Dr. Derick Brown’s lab since Fall 2015. She is a member of Lehigh’s chapter of Alpha Omega Epsilon and is a cellist in the LU Philharmonic Orchestra. She intends to continue research in graduate school to achieve her long term goal of making a difference in the world.