Development of an artificial biofilm to study the effects of a single microcolony on mass transport

Alginate harvested from a mucoid strain of Pseudomonas aeruginosa, grown on YTG agar plates, was used to develop an artificial biofilm. The alginate was sterilized and fixed to a glass slide where it served as the biofilm matrix. High densities of P. aeruginosa were injected into specific locations within the alginate matrix to represent microcolonies similar to those found in natural biofilms. Dissolved oxygen microelectrodes, with tip diameters of 10 mu m, were constructed and used to measure oxygen profiles through the artificial biofilm. Using mathematical models the kinetic parameters for microbial respiration were extracted from the profiles. The activity of immobilized microorganisms was monitored and the dynamics of dissolved oxygen transport to a single microcolony was evaluated.