High Production of Squalene Using a Newly Isolated Yeast-like Strain Pseudozyma sp SD301

A yeast-like fungus, termed strain SD301, with the ability to produce a high concentration of squalene, was isolated from Shuidong Bay, China. The nucleotide sequence analysis of the internal transcribed spacer (ITS) region of SD301 indicated the strain belonged to Pseudozyma species. The highest biomass and squalene production of SD301 were obtained when glucose and yeast extracts were used as the carbon and nitrogen sources, respectively, with a C/N ratio of 3. The optimal pH and temperature were 6 and 25 degrees C, with 15 g L-1 of supplemented sea salt. The maximum squalene productivity reached 0.039 g L(-1)h(-1) in batch fermentation, while the maximum squalene yield of 2.445 g L-1 was obtained in fed-batch fermentation. According to our knowledge, this is the highest squalene yield produced thus far using fermentation technology, and the newly isolated strain Pseudozyma sp. SD301 is a promising candidate for commercial squalene production.