Fatty acid patterns of film-forming yeasts and new evidence for the heterogeneity of Pichia membranaefaciens.

Total fatty acids (C14:0 to C18:3) of 50 strains assigned by classical identification methods to Pichia membranaefaciens (28), P. anomala (15), Dekkera anomala (2), D. bruxellensis (2) and Candida vini (3) were determined and data analysed by multivariate statistical procedures. Principal components cluster analysis defined six groups of strains. Thirteen strains of P. anomala formed a well-defined cluster, whereas P. membranaefaciens was split into three groups. The taxonomic status of the P. membranaefaciens strains was evaluated by determination of the G + C content and DNA-DNA hybridization. The results provided evidence in support of P. membranaefaciens encompassing distinct species. Only eight strains were certified as P. membranaefaciens and six were included in the same cluster, indicating that numerical analysis of fatty acid profiles points to genetic differences which remain undetectable by conventional phenotypic tests.