The role of ethanol in preventing biofilm formation of Penicillium purpurogenum

Abstract

The use of fungi in biotechnology requires that no cell loss takes place; a maximal level of cell-nutrient interaction is required to achieve efficient performance. The occurrence of high cell densities or loss of biomass through cell-surface interaction prevents the desired result. The main purpose of adding ethanol was to manipulate the cell-cell and cell-surface adhesion through manipulating cell surface properties. Scanning electron microscopy indicated that the type of surface and its treatment with ethanol controls the adhesion and biofilm formation of Penicillium purpurogenum. Gamma irradiation slightly affected the wettability of polystyrene strips at 0.5 and 1 kGy, thus slightly decreasing the adhesion, but was not as effective as using ethanol to control the adhesion. The presence of ethanol in the media caused a decrease in surface-bound proteins from 0.348 to 0.133 mg/ml, while surface exopolysaccharides showed a minimal decrease. Ethanol induced oxidative stress which reached its peak when 2.5 % v/v ethanol was added to the media; this was represented by both intracellular and extracellular catalase and lipid peroxidation. On the other hand, fungal biomass and pigment showed a decrease as the ethanol concentrations increased. Therefore, ethanol could be employed to control the surface properties of a fungus, and to inhibit biofilm formation to obtain a high surface area for the fungus to be employed in any biotechnological process. © 2013 Springer-Verlag Berlin Heidelberg and the University of Milan.