15-17: Optimising the lipid profile, to produce either a palm or rapeseed oil substitute, by manipulation of the culture conditions for Rhodotorula glutinis.

Lipids are a vital feedstock to produce renewable liquid fuels compatible with the current distribution, road transport and aviation infrastructure.  They are also widely used in the cosmetics and food industries. The fatty acid profile of the lipids is extremely important in determining their eventual use. Oils high in oleic acid such as rapeseed oil are the most suitable biodiesel feedstock and also offer the highest potential for further chemical upgrading to polymers, higher value chemicals or aviation fuels. Alternatively, to replace palm oils in the cosmetic or food industries, high levels of saturated lipids are necessary.

These oils can be produced sustainably from oleaginous microorganisms grown using waste resources. The red oleaginous yeast, Rhodotorula glutinis, can produce high yields of lipid in the form of triglycerides, making it a promising alternative to current crop-based oils.  R. glutinis has a simple fatty acid profile which can change depending on the environmental conditions. In this study, a design of experiments was used to determine whether R. glutinis could produce a feedstock high in either oleic acid (18:1) or palmitic acid (16:0). This was achieved through alteration of three input variables: sugar concentration, ammonium concentration and temperature, allowing for the tailoring of the lipid produced, while maintaining high lipid and biomass yields. This demonstrates that by careful manipulation of the growth conditions R. glutinis can produce a triglyceride feedstock specific to application.