Optimization of Squalene Production by sp. P4-22.

Squalene is an important bioactive substance widely used in the food, pharmaceutical, and cosmetic industries. Microbial production of squalene has gained prominence in recent years due to its sustainability, safety, and environmental friendliness. In this study, a mutant strain, sp. P4-22, with enhanced squalene-producing ability, was obtained through atmospheric and room temperature plasma mutagenesis of the previously screened squalene-producing yeast sp. SD301. The P4-22 strain demonstrated the ability to produce squalene using various carbon and nitrogen sources. We optimized the culture conditions by employing cost-effective corn steep liquor as the nitrogen source, and the optimal pH and sea salt concentration of the medium were determined to be 5.5 and 5 g/L, respectively. Under optimal cultivation conditions, the biomass and squalene production reached 64.42 g/L and 2.06 g/L, respectively, in a 5 L fed-batch fermentation. This study highlights the potential of sp. P4-22 as a promising strain for commercial-scale production of squalene.