Research Interests:

Biochemical engineering, Systems biology, Metabolic engineering, Biofilm physiology and control

Research Summary:

Metabolic Network Analysis and Engineering: Life is comprised of thousands of chemical reactions organized into complex networks. These networks channel and transform nutrients acquired from the environment into products like work, heat, and new life. To understand the chemistries of life, the highly branched and highly coupled networks must be understood. We are utilizing a network analysis system known as elementary flux mode analysis to study the properties of microbial reaction networks. The method identifies every unique, mathematically defined chemical reaction permutation within a network. Starting with these chemical reaction modules, we assemble concise mathematical blueprints of microbial metabolisms.

The network analysis research is integrated into practical microbial engineering and microbial physiology studies. Analogous to traditional chemical engineering, we apply an understanding of specific chemistries to control the conversion of inexpensive or undesirable compounds into more valuable or more desirable products. However, instead of using traditional chemical engineering approaches involving inorganic catalysts and high temperatures, we are using molecular biology and metabolic blueprints obtained from network analysis to engineer useful processes catalyzed by microbes. Applications of this work include environmentally critical processes like efficient nutrient recycling and bioremediation of contaminated sites. The research can also be used to optimize biotechnological processes like the production of biofuels and biomaterials from renewable resources. In addition by advancing our metabolic understanding of microbial pathogens, it should be possible to improve prevention and treatment strategies for medical infections.

Anti-Biofilm Coatings: Biofilms are 3-dimensional microbial communities encapsulated in a self-produced polymeric matrix. The combined physical and physiological properties of biofilms make them very difficult to control. Common planktonic microbial control strategies like the use of antibiotics or oxidizing chemicals are typically limited in their efficacy at inhibiting or removing biofilms. Biofilms can grow on most moist surfaces making them a ubiquitous problem faced by a broad range of disciplines including the medical field. For instance, the National Institutes of Health estimates that up to 80% of human infections are related to biofilms. Implanted medical devices like catheters and artificial joints often serve as a vector for biofilm related infections.

We are studying surface coating strategies for retarding or preventing the formation of biofilms in collaboration with the Center for Biofilm Engineering. The strategies do not utilize the traditional paradigm of antimicrobial agents imbedded in an inert polymeric material. Instead, the system utilizes a naturally occurring polysaccharide as both the coating material and an actual anti-biofilm agent. The coating material possesses inherent, broad spectrum, antimicrobial properties, is biocompatible and is quite non-toxic to mammalian cells. The coatings have been shown to be effective at retarding or preventing the formation of biofilms under medically relevant conditions. The coatings have performed significantly better than more traditional coating systems impregnated with antimicrobial agents like chlorhexidine. The findings suggest this polysaccharide based strategy has strong potential for applications on surfaces susceptible to biofilm formation like implantable medical devices.