91 – Xanthophyllomyces Golubev

Publisher Summary This chapter focuses on Xanthophyllomyces genus and its member species. The cells of this genus are encapsulated and reproduce by enteroblastic budding. True mycelium is absent and chlamydospores may be present. Slender cylindrical holobasidia arise mainly after conjugation between a cell and its bud, and basidiospores are produced terminally on minute pegs. Carotenoid pigments are synthesized, which give cultures an orange to salmon-red color. The sole member species of this genus is Xanthophyllomyces dendrorhous. The cells of this species, after undergoing growth in glucose-yeast extract-peptone water for three days at 18° C, become spheroidal to ovoidal with small capsules. After one month of growth on Difco yeast morphology agar at 18° C, the streak culture becomes orange to salmon-red, nearly smooth, glossy to semi-dull, and soft. After 10 days of slide cultures on corn meal agar at 18° C, a rudimentary pseudomycelium may occur. Formation of basidiospores is observed on agar media containing polyols, pentoses, or D-lyxose, except for D-mannitol andL-arabinose.