Effects of butanol on high value product production in Schizochytrium limacinum B4D1

Schizochytrium is a microalgae-like fungus and is widely used for producing docosahexaenoic acid (DHA). It is also a promising source of squalene and carotenoids. However, few fermentation strategies are available in enhancing squalene and carotenoid content in Schizochytrium. This study showed that butanol addition had multiple effects on Schizochytrium limacinum B4D1. First, butanol addition altered the lipid content of cells. Second, 6 g/L of butanol decreased the proportion of DHA by nearly 40%. Third, the squalene content increased 31-fold in the presence of 6 g/L butanol. Finally, cells accumulated more carotenoids upon butanol addition. Specifically, when cells were treated with 8 g/L butanol, the astaxanthin content increased to 245 times than that of the untreated control. These results are helpful for the commercial exploitation of Schizochytrium in producing squalene and carotenoids.