THE YEAST KLUYVEROMYCES-LACTIS AS AN EFFICIENT HOST FOR HETEROLOGOUS GENE-EXPRESSION

Several different yeast species have been developed into systems for e fficient heterologous gene expression. In this paper we review foreign gene expression in the dairy yeast Kluyveromyces lactis. This yeast p resents several advantageous properties in comparison to other yeast s pecies. These include its impressive secretory capacities, its excelle nt fermentation characteristics on large scale, its food grade status and the availability of both episomal and integrative expression vecto rs. Moreover, in contrast to the methylotrophic yeasts that are freque ntly used for the expression of foreign genes, K. lactis does not requ ire explosion-proof fermentation equipment. Here, we present an overvi ew of the available tools for heterologous gene expression in K. lacti s (available promoters, vector systems, etc). Also, the production of prochymosin, human serum albumin and pancreatic phospholipase by K. la ctis is discussed in more detail, and used to rate the achievements of K. lactis with respect to other micro-organisms in which these protei ns have been produced.