Cellular changes due to biofilm formation: influence of flow regime

Abstract

A comparison of the biochemical and metabolic characteristics of Pseudomonas fluorescens in planktonic state and cells developed in biofilms is presented in this study. The effects of the flow regime (turbulent and laminar) under which the biofilms were formed were also studied. The comparative study was performed by assessing the respiratory activity, the cell number and the amount of cellular proteins and polysaccharides. The results obtained showed that planktonic cells were more active, and had a higher content of proteins and polysaccharides per cell than the cells present in biofilms. Nevertheless, the number of cells per mg of biological mass is much higher in biofilms. Concerning the comparison between biofilms formed under different flow regimes, the ones formed under turbulent flow were more active and had a higher number of cells than biofilms formed under laminar flow. The intracellular proteins and polysaccharides are in a higher extent in biofilms formed under laminar flow. Furthermore, SEM photomicrographs show that biofilms formed under different flow regimes also look very differently.