Schizochytrium-derived omega-3 polyunsaturated fatty acids (e.g., docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)) are proven to be health-beneficial bioactive substances that have been widely applied in the pharmaceutical, nutraceutical, and food industries. In this work, the newly isolated
Schizochytrium sp. FJ-1 strain was selected to investigate the effects of salinity on the growth performance, lipid production, DHA yield, and positional distribution of triacylglycerols (TAGs). In addition,
Schizochytrium sp. 20888 was used as a control strain. The obtained results showed that
Schizochytrium sp. FJ-1 could grow with a low biomass in the absence of sea salt; however,
Schizochytrium sp. 20888 did not grow in the medium without sea salt. Moreover,
Schizochytrium sp. FJ-1 achieved the highest biomass in 10‰ salinity, whilst
Schizochytrium sp. 20888 attained the greatest biomass in 40‰ salinity. In terms of the total lipid content and TAG fraction percentage,
Schizochytrium sp. FJ-1 grown in 5–20‰ salinity had high total lipid contents (57.04–60.02%), with TAGs accounting for over 90% of the lipid fraction. The highest DHA contents for total lipids (41.38%) and TAGs (40.18%) were obtained when
Schizochytrium sp. FJ-1 was grown under 10‰ salinity conditions. Additionally, under the same culture condition, EPA contents of lipids and TAGs were significantly higher for
Schizochytrium sp. FJ-1 compared with
Schizochytrium sp. 20888. Furthermore, nuclear magnetic resonance analysis found that the salinity level had a distinct impact on the positional distribution of DHA in TAGs in these two
Schizochytrium strains.
Schizochytrium sp. FJ-1 grown under 40‰ salinity conditions produced TAGs with the greatest percentage of
sn-2 DHA (81.24%). The percentages were higher than those found for the other groups of this microalga and
Schizochytrium sp. 20888. Taken together,
Schizochytrium sp. FJ-1 could be a potential candidate to produce highly valued DHA lipids or TAG bioproducts by regulating salinity.
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