Bioaccumulation of Rare Earth Elements from Waste Luminophores in the Red Algae, Galdieria phlegrea

Growth under Different Trophic Regimes and Synchronization of the Red Microalga Galdieria sulphuraria

“…It was found previously that G. sulphuraria was adapted to an acidic pH, but changes in pH can affect the composition of the biomass [11,23]. Furthermore, pH values can differ, even for closely related species [12,16]. For further synchronization and cell cycle experiments, pH 3 was chosen.…”

“…The unicellular red alga Galdieria sulphuraria (Galdieri) Merola, 002 was obtained from the Algal Collection of Dipartimento delle Scienze Biologiche, Section of Plant Biology, University "Federico II" of Naples, Italy. The algae were grown in modified Galdierianutrient medium [11] Glycerol (to a final concentration of 1% (v/v)) (Penta, Chrudim, Czech Republic) was added as a source of energy and carbon for the mixotrophic cultivations [16]. The algae were routinely sub-cultured on culture plates containing Galdieria-nutrient medium solidified with 3% agar every three weeks.…”

“…They thrive in a wide range of temperatures up to 56 • C and in acidic environments with pH values below 1.0 [9,10]. The adaptation of cyanidialean red algae to high temperature and low pH [9,11] and their resistance to high salt [12], numerous toxic metals [13,14], as well as rare earth elements (REEs) [15,16] is unusual among other eukaryotic algae and makes it a promising candidate for biotechnological exploitation [17,18]. Galdieria is not only resistant to high levels of metals and rare earths, but it can also accumulate them inside the cells [14][15][16]19].…”

“…The adaptation of cyanidialean red algae to high temperature and low pH [9,11] and their resistance to high salt [12], numerous toxic metals [13,14], as well as rare earth elements (REEs) [15,16] is unusual among other eukaryotic algae and makes it a promising candidate for biotechnological exploitation [17,18]. Galdieria is not only resistant to high levels of metals and rare earths, but it can also accumulate them inside the cells [14][15][16]19]. G. sulphuraria is usually cultivated for several biotechnological applications such as recycling of valuable components and nutrients from low pH wastewaters; production of phycocyanin as a main pigment even under heterotrophic conditions; cultivation for biofuels, due to its high resistance to contamination, even under heterotrophic conditions; production of glycogen; nutritional applications (reviewed in [17]).…”

Impacts of Phosphorous Source on Organic Acid Production and Heterotrophic Bioleaching of Rare Earth Elements and Base Metals from Spent Nickel-Metal-Hydride Batteries

“…Typically, NiMH batteries are recycled by using them as a cheap nickel source in stainless steel production, but this approach results in loss of the valuable shares of cobalt and REEs to the smelter slags [6,7]. The existing physicochemical recycling routes for recovery of base metals and REEs from spent NiMH batteries have mainly been studied in laboratory and pilot scale while their scale up and commercialization has been hindered by the complexity and high costs of the processes as well as generation of remarkable amounts of hazardous waste [3,8,9].…”