Examining solvent/fermentation broth interfaces

A microscopic method was developed to allow the visual investigation of cells at solvent/fermentation broth interfaces, using glass capillary tubes of set dimensions. This method allows the interfacial distribution of cells to be investigated and photographed. Fermentation broths of a dimorphic micro-organism Aureobasidium pullulans (which can exist in both a filamentous and yeast-like form), and the solvent n-decanol were chosen for this study. It was found that cell behaviour was dependent on the cell morphology, with the filamentous cells gathering outside the viewing range of the liquid/liquid interface. The yeast-like cells were randomly distributed throughout the broth, and visible in the area of the interface. The cells did not form a continuous layer at the interface, as hypothesised by Crabbe.