We focused on the production of DHA-containing microbial lipids by Aurantiochytrium sp. using of defatted soybean (DS) as a nitrogen source. DS is a plant biomass that could provide a sustainable supply at a low cost. Results showed that Aurantiochytrium sp. could not directly assimilate the DS as a nitrogen source but could grow well in a medium containing DS fermented with rice malt. When cultivated in a fermented DS (FDS) medium, Aurantiochytrium sp. showed vigorous growth with the addition of sufficient sulfate and chloride ions as inorganic nutrients without seawater salt. A novel isolated Aurantiochytrium sp. 6-2 showed 15.8 ± 3.4 g/L DHA productivity (in 54.8 ± 12.1 g/L total fatty acid production) in 1 L of the FDS medium. Therefore, DHA produced by Aurantiochytrium sp. using FDS enables a stable and sustainable DHA supply and could be an alternative source of natural DHA derived from fish oil.
Keywords: Aurantiochytrium sp; fermented defatted soybean; plant biomass; polyunsaturated fatty acid; ω3-docosahexaenoic acid.
© The Author(s) 2024. Published by Oxford University Press on behalf of Japan Society for Bioscience, Biotechnology, and Agrochemistry.