Animal-free media optimization for recombinant protein production in Pichia pastoris

Pichia pastoris are a rapidly becoming the organism of choice for recombinant protein expression. Although P. pastoris can be grown in both complex and synthetic media, complex media can have a number of benefits related to recombinant protein fermentations including increased biomass and improved product quantity and quality. In recent years there has been a growing trend toward looking at animal component free complex media in yeasts to reduce the risk of contamination of raw materials with adventitious agents.

In this study growth, product quantity and product activity were analysed across a range of P. pastoris strains. This was achieved through the performance of high throughput screening assays in micro titre plates looking at the effect that Sheffield yeast extracts, peptones and combinations had on O.D.  The successful media samples from this screening were then tested at a larger scale in shake flasks, where the effect of the media on the product quantity and activity was analysed in comparison to an animal based media formulation. Lastly, the successful media at this stage were then tested in a 1L fermenter, where glycerol consumption, methanol consumption, O.D. and product quantity and quality were all analysed throughout the fermentation.

In this study a number of different animal component free media’s were identified that can compete with animal based media formulations. These media formulations will provide our customers with the ability to remove animal derived components from their media without adversely affecting the performance of their process.