Lab-scale optimization of aurantiochytrium sp. culture medium for improved growth and DHA production

Thraustochytrids have gained increasing relevance over the last decades, due to their fast growth and outstanding capacity to accumulate polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA). In this context, the present work aimed to optimize the growth performance and DHA yields by improving the culture medium of Aurantiochytrium sp. AF0043. Accordingly, two distinct culture media were optimized: (i) an inorganic optimized medium (IOM), containing only monosodium glutamate and glucose as nitrogen and carbon sources, respectively; and (ii) an organic and sustainable waste-based optimized medium (WOM), containing corn steep powder and glycerol, added in fed-batch mode, as nitrogen and carbon sources, respectively. Overall, the lab-scale optimization allowed to increase the biomass yield 1.5-fold and enhance DHA content 1.7-fold using IOM. Moreover, WOM enabled a 2-fold increase in biomass yield and a significant improvement in lipid contents, from 22.78% to 31.14%. However, DHA content was enhanced almost 3-fold, from an initial content of 10.12% to 29.66% of total fatty acids contained in the biomass. Therefore, these results strongly suggest, not only that the production pipeline was significantly improved but also confirmed the potential use of Aurantiochytrium sp. AF0043 as a source of DHA.