Ogataea methanolica (Makig.) Kurtzman & Robnett 2010

Egypt.

Colonies. Growth on 5% malt extract agar: after 3 days at 25°C, the cells are spheroidal to ovoidal, (1.9-6.0) × (2.0- 8.8) μm, and occur singly, in pairs or in clusters. Growth is cream-coloured, smooth, glistening and butyrous. Growth on the surface of assimilation media: pellicles are not formed. Dalmau plate culture on morphology agar: after 7 days at 25°C, growth under the cover glass shows neither pseudohyphae nor true hyphae. Aerobic growth is pale tannish-white, smooth, glistening and butyrous with an entire to lobed margin. Some strains produce a faint odour of esters. Teleomorph. Formation of ascospores: asci may show parent-bud conjugation or conjugation between independent cells. One to four hat-shaped spores are produced in each ascus, and the spores are freed soon after formation. Because conjugations between a cell and its bud are common in ascosporogenous cultures, this species appears to be homothallic. Ascospores were observed on 5% malt extract agar and Difco yeast morphology agar after 4-7 days at 25°C.

Ogataea methanolica is a homothallic haploid organism that offers many of the advantages of a eukaryotic expression system such as protein processing and protein folding, while being as easy to manipulate as E. coli or Saccharomyces cerevisiae. It is faster, easier, and less expensive to use than other eukaryotic expression systems such as baculovirus or mammalian tissue culture, and generally gives higher expression levels. As a yeast, it shares the advantages of molecular and genetic manipulations with Saccharomyces, and it has the added advantage of 10- to 100-fold higher heterologous protein expression levels. These features make P. methanolica very useful as a protein expression system.