Schizochytrium

Certain species produce large amounts of docosahexaenoic acid (DHA)^[4] and are grown commercially for production of algae oil for animal feeds, biomass, biofuels and direct human consumption in supplements and additives.^[5]

In 2016, juvenile Nile tilapia were given a feed containing dried Schizochytrium in place of fish oil. When compared to a control group raised on regular feed, they exhibited higher weight gain and better feed conversion, and their flesh was higher in omega-3 fatty acids.^[6][7] A 2020 study showed similar results and combined the feed with Nannochloropsis oculata for an entirely fish-free feed.^[8][9]

DHA synthesis in Schizochytrium does not involve membrane-bound desaturases or fatty acid elongation enzymes such as those described for other eukaryotes.^[10][11] Instead it is thought that DHA synthesis in Schizochytrium occurs via a Polyketide synthase (PKS)-based pathway, although the primary structures of the Polyketide synthases do not conform to any known class of PKS proteins.^[10][12] Homology between Shewanella and Schizochytrium PKS genes suggests that the genes involved in this pathway underwent lateral gene transfer.^[10]