Effects of Hydrocarbons on the Morphology of Candida tropicalis pK 233

Candida tropicalis pK 233 exhibited marked morphological changes depending upon carbon sources for growth. Although the yeast showed a typical yeast-like development when grown on glucose, the cells grown on hydrocarbon or ethanol were composed of a mixture of filamentous-form (F-cells) and yeast-form cells (Y-cells). The carbon chain lengths of n-alkanes tested as growth substrates had a significant influence on the ratio of F-cells to Y-cells. Electronmicroscopic observation revealed that a hypha was divided by septa into several cells.

Separation of Y-cells and F-cells was achieved by using a suitable filter cloth. F-cells gave a high Qo₂ value compared with Y-cells when hydrocarbon was used as oxidation substrate, even though there was little difference between the respiratory activities of these two cells measured with glucose.