Abstract

The chlorophtye Coccomyxa sp. (strain onubensis) growing under either inorganic phosphorus or sulfur starvation showed, unlike other non-extremophile microalgae, the ability to grow still for a period of 2 weeks with retention of high activity of photosystem II, due to P and S reserves in the microalga. Lutein and beta-carotene contents slightly increased for a few days in nitrogen-lacking cultures only, with no major impact on productivity due to cease of growth. Maximum fatty acid content of Coccomyxa sp. (strain onubensis) growing in nutrient-lacking culture media accounted for about 13 % of dry biomass and about 50 % of the total lipid fraction, linolenic (C18:3) being the most abundant fatty acid. The lipid content of this microalga is on the average of non-extremophile microalgae, but it has the advantage of producing in highly acidic culture media (pH 2.5, and even lower) which allow its outdoor production-preserving cultures from other microalgae contamination. Nutrient-limited cultures showed a significant increase in the intracellular activity levels of the enzymes glutathione reductase (GR), ascorbate peroxidase (APX) and catalase (CAT), indicating a connection between nutrient deprivation and oxidative stress in Coccomyxa sp. (strain onubensis).