CAREER: Effects of Surfaces on Bacterial Metabolic Activity and Survial: Examination of a Physiochemical/Bioenergetic Mechanism

Lehigh University, Bethlehem PA

Investigators

Abstract

0134362 Brown It has long been recognized that the adhesion of bacteria to surfaces can result in enhanced metabolic activity. This can be beneficial, such as with attached-growth bioreactors for water and wastewater treatment, biodegradation of subsurface contaminants and with nutrient cycling in soils. However, it can also be harmful, such as with bacterial survival and growth in water distribution systems, pathogen growth on medical implants and equipment, plaque formation on dental surfaces, and bacterial attachment in pipelines with concurrent degradation of the pipelines and the fluids they carry. Most research in this area has focused on the availability of nutrients and growth substrate adsorbed to the solid surface. The research approach proposed addresses this issue from a different viewpoint by considering specific interactions between the surface and the bacterial cell wall. The approach examines the link between two disparate theories, one involving colloid deposition processes and the other involving cell membrane bioenergetics. Specifically, this approach focuses on the interactions between the physiochemical charge-regulation process, which occurs as a surface containing ionizable groups (e.g. bacterial cells) approaches another surface, and cellular membrane bioenergetics the chemiosmotic theory of Peter Mitchell - which directly impacts metabolic activity and survival. The proposed research project examines the link between the charge-regulation and chemiosmotic processes through numerical and experimental investigations. Numerical simulations of the proton motive force and the charge-regulation process will be used to design and interpret experiments that will systematically examine the effects of bacterial, solid surface, and solution properties on bacterial metabolic activity and survival. The ultimate goal is to elucidate the nature of the link between the charge-regulation and chemiosmotic processes, allowing these models to be used as a tool to assess biochemical processes in natural systems and to assist in the selection or design of surfaces in engineered systems based on bacteriological constraints. The main educational thrust of this proposal takes a step back and focuses on Environmental Engineering curricula taught in middle- and high-schools. To reach the widest possible number of teachers, the PI proposes to develop a comprehensive web site. A main benefit of the web format is that the site will be a living document, which will evolve based on feedback as the curricula is used in the classroom. This site will be developed in conjunction with the National Science Teachers Association (NSTA). The NSTA has agreed to assist in setting-up reviewers in order to ensure that the site content and format are tailored to the needs of middle- and high-school teachers.***