Pyrolysis-gas chromatography-mass spectrometry of the yeast genera Cryptococcus and Rhodotorula

A comparative study of different species from the yeast genera Cyptococcus and Rhodotorula, isolated from rotted wood, was camed out using analytical pyrolysis-gas chromatography-mass spectrometry. The predominant compounds obtained were various alkanes, cyclic ketones, indolic compounds, alkanoic acids and furan derivatives, which are pyrolytic products of lipids, proteins and carbohydrates. The amount of some pyrolytic products showed significant differences between both genera. A high proportion of an alkyl indole was characteristic of Cyptococcus, which also showed the highest ratio between products derived from lipids and those derived from carbohydrates. The Cypfococcw-like state of Tremella aurantia, hardly distinguishable from Cypfococcus laurentii on the basis of characters currently used for yeast species identification, was recognized by its characteristic pyrolysis pattern, which showed a high predominance of undecane. Multivariate numerical analyses were performed from the relative abundance of the different pyrolysis products. The results of multidimensional scaling from pyrolysis data were compared with those obtained from the current taxonomic characteristics, showing the separation between Cyptococcw and Rhodoforula and a considerable intraspecific variation. The agreement between pyrolysis and taxonomic characters was also shown by the results of the canonical correlation between both sets of data.