Recovery of rare earth elements from luminophores using the red alga Galdieria

The red alga Galdieria phlegrea was used as an experimental organism to test bioaccumulation of rare earth elements (REEs) from luminophores. Algal cells were cultured mixotrophically in a liquid medium with addition of glycerol as a source of carbon. Luminophores from two different sources (fluorescence lamps and energy saving light bulbs) were added into the medium in the form of a powder. The cell number was monitored to follow the growth of the algal culture. The content of single REEs in the luminophores and the biomass were determined using ICP-MS. The most abundant element in both luminophores was yttrium representing about 90%. The growth of cultures grown in the presence of both luminophores was comparable with control. Total amount of accumulated REEs in biomass differed with type and concentration of the luminophore used for treatment. The most abundant element accumulated in the biomass was lanthanum. To conclude, Galdieria phlegrea can grow in the presence of luminophores and accumulate REEs. The enriched biomass is a promising template for biotechnological applications. Project was supported by the program Interreg V-A ATCZ172, the National Programme of Sustainability I, ID: LO1416 and by Institutional Research Concept no. AV0Z61388971.