Abstract
Sulphur (S) and selenium (Se) are chemically similar. Once Se is taken up, it substitutes S in S-containing amino acids. This study investigated the effect of S on selenite accumulation in the microalga Nannochloropsis oceanica. [0-28 mM] S concentrations and selenite concentrations of 0 and 30 µM were tested. S concentrations of ≤ 3 mM led to decreased cell growth whereas cultures with ≥ 4 mM were not growth limited. Se accumulation increased up to 8-fold when using S ≤ 2 mM and decreased with S 28 mM. The average relative abundance of organic Se species was selenomethionine (SeMet) 98.2%, selenocystine (SeCys2) 1.4% and selenomethyl selenocysteine (SeMeSeCys) 0.4%. Total fatty acids were not affected by S limitation or Se presence. This is the first study on the effect of S on selenite accumulation, organic Se speciation of N. oceanica and its potential as an organic Se-enriched food/feed ingredient.
Highlights:
Sulphur deplete and limiting conditions result in in more Se accumulation in N. oceanica
The dominant Se species in N. oceanica is selenomethionine (SeMet) (>97%)
Organic Se speciation in N. oceanica is SeMet>SeCys2>SeMeSeCys>Se
Selenium enrichment in N. oceanica does not affect total fatty acids accumulation
References
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Guimarães, B.O., de Boer, K., Gremmen, P., Drinkwaard, A., Wieggers, R., H. Wijffels, R., J. Barbosa, M., D’Adamo, S., 2021a. Selenium enrichment in the marine microalga Nannochloropsis oceanica. Algal Res. 59, 102427. https://doi.org/10.1016/j.algal.2021.102427
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Guimarães, B. O., García-Barrera, T., Arias-Borrego, A., Gremmen, P., H. Wijffels, R., J. Barbosa, M., & D’Adamo, S. (2022). Effect of sulphur on selenium accumulation and speciation in Nannochloropsis oceanica. Journal of Functional Foods, 96(August). https://doi.org/10.1016/j.jff.2022.105215
Keywords: Nannochloropsis oceanica, selenium, selenite, aquaculture, Se speciation, chemical similarity
Results