The value of lipid composition in the taxonomy of the Schizosaccharomycetales

In this study, the lipid fractions i.e. neutral (NL), phospho-(PL) and glycolipids (GL) with associated fatty acids (FAs) of 54 strains, representing the Schizosaccharomycetales, were analyzed during stationary growth phase and compared. Trace amounts of linoleic acid (18:2) were present in most of the strains representing Schizosaccharomyces. An increased percentage 18:2 was observed in the PL fraction when compared to the NL fraction. This is possibly related to membranes requiring polyunsaturated FAs for fluidity. On the basis of the percentage oleic acid (18:1) and 18:2 FAs in the different lipid fractions, the Schizosaccharomycetales can clearly be divided into two groups i.e. Group 1 (represented by the genus Hasegawaea) comprising strains producing relatively large amounts of 18:2 and relatively low amounts of 18:1 when compared to Group 2 (represented by the genus Schizosaccharomyces comprising Schizosaccharomyces octosporus and Schizosaccharomyces pombe). These results are in accordance with 18S and 26S rRNA base sequence analyses and emphasize the difference between the genera Hasegawaea and Schizosaccharomyces. Utilizing gas chromatography-mass spectrometry analyses, it was found that these strains were all capable of producing gamma-linolenic acid. This further emphasizes the uniqueness of this order in the Dikaryomycota.