COMPARISON OF THE MORPHOLOGIES OF A FLOTABLE AND NON FLOTABLE STRAIN OF SACCHAROMYCES-CEREVISIAE

In a previous paper, Saccharomyces cerevisiae LBG H620 and DSM 2155 we re compared regarding their ability to float. LBG H620 did not float a t all; DMS 2155 floated excellently. The investigations of the cells' surface properties indicated that yeast LBG H620 has a high surface hy drophilicity and a high electrokinetic potential; yeast DSM 2155 posse sses high hydrophobicity and a low electrokinetic potential [Tybussek et al. (1994) J Appl Microbiol Biotechnol 41:13-22]. In the present pa per, the morphologies of these two yeast strains are compared. Strain LBG H620 formed only single or budding cells, strain DSM 2155 formed c ell aggregates, their size depending on the cultivation conditions: in the presence of adequate substrate concentration cell aggregates were formed, and during substrate limitation single cells dominated. Durin g respiratory growth rather small spherical aggregates and during resp iratory/fermentative growth long-string aggregates were observed.