ABSTRACT
Only a limited number of yeast species are able to use methanol as a primary carbon source (Hazeu et al. 1972). In that regard, the Phillips Petroleum Company (PPC) was the rst to develop media and fermentation protocols for growing P. pastoris in continuous cultures at high cell densities to produce single-cell proteins (SCP) for feedstock from methanol (Cereghino et al. 2000). Unfortunately, the oil crisis of the 1970s rendered this process unattractive due to the high cost of methanol. In the following decade, PPC and the Salk Institute Biotechnology/Industrial Associates Inc. (SIBIA, La Jolla, CA) developed tools for heterologous protein production in P. pastoris. As a result, recombinant expression vectors, methods for transformation, selectable markers, and fermentation processes were developed to exploit the productive potential of this yeast (Cregg et al. 1993; Rosenfeld 1999). Expression systems developed for P. pastoris were patented by Research Corporation Technologies (Tucson, AZ) in 1993 and are available as a kit from Invitrogen Corporation (Carlsbad, CA). Actually, more than 1000 proteins have been cloned and expressed in P. pastoris (Cregg et al. 2000; Damasceno et al. 2012). P. pastoris has also been selected by several protein production platforms for genomics programs (Yokoyama 2003).
