Poster Session

Surface Rheology of Bacterial Films at the Hexadecane-Water Interface

Zhewen Kang, PhD student in Chemical Engineering

Supervisor - Dr.Gray and Dr.Yeung

Bacterial films formed at hydrocarbon-water interfaces have important relevance to such applications as bioremediation and enhanced oil recovery. Although much is known about the biochemical aspects of bacteria at interfaces, the physics of these films (e.g. modification of oil-water interfacial tension and creation of surface viscoelasticity) remains a largely unexplored subject. In this study, the interfacial rheology of bacterial films is examined using the dynamic pendant drop technique. The bacterial films are formed from adsorption of Acinetobacter venetianus RAG-1 at the hexadecane-water interface. When in their stationary phase, the cells appear to have no effect on the equilibrium tension as they accumulate at interface. Upon transient excitations, however, the films are seen to exhibit very “non-traditional” rheological properties. In addition, bacterial associations at the interface and the response of the cell layers to physical perturbation are examined microscopically. These results can offer insight into the interaction of bacteria at oil/water interfaces.