Effect of phosphorus limitation on Se uptake efficiency in the microalga Nannochloropsis oceanica

Microalgae are considered an efficient accumulator and promising source of Se for feed additive purposes. This study aimed at investigating, for the first time, the effect of phosphorus limitation on Se accumulation and uptake efficiency in N. oceanica. A range of phosphorus concentrations (0-2470 mu M) were tested in either the presence or absence of sodium selenite (0, 5, 30 mu M). Se accumulation was increased up to 16-fold and Se uptake efficiency was increased up to 3.6-fold under phosphorus growth-limiting concentrations. N. oceanica was then cultivated in a 1.8 L flat-panel photobioreactor in batch operation under two phosphorus growth-limiting concentrations (250 and 750 mu M) where the accumulation of Se in the microalgal biomass, as well as its presence in the spent medium were analysed. This study is the first to investigate the effect of phosphorus limitation for increasing Se accumulation in microalgae, and to prevent the release of Se in wastewater.

Automated summary

This study investigates the effect of phosphorus limitation on Se accumulation and uptake efficiency in N. oceanica for the first time. Se accumulation increased up to 16-fold and Se uptake efficiency increased up to 3.6-fold under phosphorus growth-limiting concentrations. N. oceanica was then cultivated in a bioreactor with two phosphorus growth-limiting concentrations, analyzing the accumulation of Se in the microalgal biomass and its presence in the spent medium. This study is the first to explore the effect of phosphorus limitation on increasing Se accumulation in microalgae and preventing the release of Se in wastewater.