Herman Jan Phaff: professor, mentor, friend and colleague.

Herman Jan Phaff, the father of yeast ecology, was born in the Netherlands in 1913. In his early years, he spent much time in his family's winery, which sparked his interest in microbes. Trained in the famous Delft tradition, Phaff discovered many unrecognized ecological niches of yeast, such as shellfish, rabbit stomach, frass of bark beetles, tree exudates, cactus roots, Capri figs, sewage, Drosophila flies and shrimp. He is also remembered for his pioneering work on the coevolution of yeasts, insects and plants as well as for his work on yeast beta-glucanase, which resulted in major advances in the understanding of the nature of the yeast cell wall. Phaff's legacy includes research on pectin degradation by fungal enzymes and the application of molecular approaches to yeast systematics. He discovered and described many yeasts, such as the yeast named in his honor, Phaffia rhodozyma, which led to the establishment of a very important industrial fermentation process yielding high concentrations of the pigment astaxanthin, used throughout the world to provide a natural source of this important carotenoid.