Response of alpha-tocopherol and beta-carotene production in microalgae to temperature, salinity and photon flux density
(English)In: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176Article in journal (Refereed) Submitted
Oxidative stress occurs in plant and animal cells in association with oxygen. Therefore non-enzymatic antioxidants, like α-tocopherol and β-carotene, are necessary in to prevent irreversible damages caused by reactive oxygen species. Most antioxidants or their precursors are plant-derived and any fluctuation in the synthesis of these substances will affect consumers directly. To study the effects of environmental factors on antioxidant production by microalgae, cultures of the microalgae Dunaliella tertiolecta (Chlorophyceae), Nodularia spumigena (Cyanophyceae), Prorocentrum minimum Dinophyceae), Phaeodactylum tricornutum (Bacillariophyceae) , Skeletonema costatum (Mediophyceae) and Rhodomonas salina (Cryptophyceae) were incubated for 48 h at different photon flux densities, temperatures and salinities. The initial concentrations varied widely between the cultures (α-tocopherol: 0.03 – 0.52 mg g C-1; β-carotene: 0.11 – 2.72 mg g C-1). D. tertiolecta showed increased α-tocopherol content in response to increased photon flux density. The cultures of P. minimum, P. tricornutum and S. costatum showed an increase and N. spumigena a decrease of α-tocopherol concentration with increasing temperature. Photon flux density and temperature in combination were of significant importance only for the R. salina cultures. In N. spumigena and P. tricornutum cultures, α-tocopherol concentrations increased with increasing salinity and temperature, whereas in D. tertiolecta cultures the opposite was found. In P. minimum and S. costatum cultures, salinity did not influence α-tocopherol concentration significantly. β-carotene and α-tocopherol were positively associated with each other except in D. tertiolecta and P. tricornutum. Only in one of twelve cases associations between α-tocopherol / super oxide dismutase and β-carotene / super oxide dismutase were found. It can be concluded that besides species composition of phytoplankton communities, differences in temperature and salinity contribute to the variation in antioxidant synthesis. Thus consumers must be adapted to a varying antioxidant pool.
Vitamin E; Carotenoids; Phytoplankton; Oxidative stress
IdentifiersURN: urn:nbn:se:uu:diva-130138OAI: oai:DiVA.org:uu-130138DiVA: diva2:346641