Improvement in the docosahexaenoic acid production of Schizochytrium sp. S056 by replacement of sea salt

Schizochytrium is a marine microalga that requires high concentrations of sea salt for growth, although problems arise with significant amounts of chloride ions in the culture medium, which corrodes the fermenters. In this work, we evaluated that cell growth and docosahexaenoic acid (DHA) production can be improved when using 1 % (w/v) sodium sulfate instead of 2 % (w/v) sea salt in the culture medium for Schizochytrium sp. S056. In practice, the use of sodium sulfate as the sodium salt led to chloride ion levels in the medium that can be completely removed, thus avoiding fermenter corrosion during Schizochytrium sp. S056 growth, reducing cost and increasing DHA production, and simplifying the disposal of fermentation wastewater. Additionally, we demonstrated that the osmolality of growth media did not play a crucial role in the production of DHA. These findings may be significantly important to companies involved in production of PUFAs by marine microbes.