Selenium bioaccumulation and toxicity in cultures of green microalgae

•This review summarizes the impact of Se on green microalgae with regard to its uptake, bioaccumulation and toxicity.•Se toxicity—discussed using EC50 values—depends on its chemical form and concentration and it is species-specific.•Review is also focused on intracellular Se accumulation and as a part of the detoxification process.•Better insight in the overall effect of Se on microalgae is needed for the production of valuable organic Se compounds.

The complex role of selenium (Se) in living organisms can be assessed by studying physiological, biochemical and molecular aspects of its effects on lower organisms. This review aims to summarise the impact of Se on green algae (Chlorophyta), with regard to its uptake, bioaccumulation and toxicity. It will provide a better insight into the cellular response of algae to Se stress. The biochemical steps involved in the metabolism of accumulated Se are discussed based on the literature currently available on Se assimilation pathways in higher plants and marine phytoplankton. Se toxicity—discussed here using EC50 values—depends on its chemical form and concentration and it is species-specific in the case of algae. Most of the studies are particularly focussed on intracellular Se accumulation and biotransformation to Se-amino acids as a part of the detoxification process. Better understanding of the overall effect of Se on green algae is needed to help develop new technological applications for the production of Se-enriched biomass and valuable organic Se compounds from algae.