P20: Animal-free media optimization for recombinant protein production in yeast

It has been our experience that many process scientists screen raw material components individually, particularly in the case of yeast extracts and protein hydrolysates. However, in our microbial applications laboratory, it has been determined that to fully explore the potential of peptones and yeast extracts it is essential to co-test them, taking into account possible interactions and/or synergies.

Yeasts are fast becoming one of the most important hosts for recombinant protein production.  Yeasts, like prokaryotes, are a single cell fast growing organism that can be grown at high densities and can be easily genetically manipulated. Unlike prokaryotes, yeasts have an advantage in that they possess a secretory pathway resulting in glycosylation of the target protein, making them an extremely useful host for the production of recombinant proteins.

Yeast is capable of growing in complex and synthetic media. However, complex media can have certain advantages with regard to both biomass and protein production/quality. In recent years there has been a growing trend towards the use of non-animal media components. This relates to a number of issues that have arisen including the mycoplasma contamination (1970’s), endotoxin issues (1980’s) and BSE scares (1990’s). Following this trend the primary focus of this study was optimizing non-animal complex media formulations which contributed to an increase in biomass and/or protein production/quality in yeast.

Three of the most popular yeasts used for the production of recombinant proteins are Saccharomyces cerevesiae, Pichia pastoris and Hansenula polymorpha and a number of these strains were used in this study.