Cell factory applications of the yeast Kluyveromyces marxianus for the biotechnological production of natural flavour and fragrance molecules.

Kluyveromyces marxianus is emerging as a new platform organism for the production of flavour and fragrance (F&F) compounds. This food-grade yeast has advantageous traits, such as thermotolerance and rapid growth, that make it attractive for cell factory applications. The major impediment to its development has been limited fundamental knowledge of its genetics and physiology, but this is rapidly changing. K. marxianus produces a wide array of volatile molecules and contributes to the flavour of a range of different fermented beverages. Advantage is now being taken of this to develop strains for the production of metabolites such as 2-phenylethanol and ethyl acetate. Strains that were selected from initial screens were used to optimize processes for production of these F&F molecules. Most developments have focused on optimizing growth conditions and the fermentation process, including product removal, with future advancement likely to involve development of new strains through the application of evolutionary or rational engineering strategies. This is being facilitated by new genomic and molecular tools. Furthermore, synthetic biology offers a route to introduce new biosynthetic pathways into this yeast for F&F production. Consumer demand for biologically-synthesized molecules for use in foods and other products creates an opportunity to exploit the unique potential of K. marxianus for this cell factory application.