Boron bio-mining by high boron-tolerant native microalgae in Turkey and boron toxicity in the aquatic environment

Boron (B) is one of the most important trace elements. Turkey has the largest B reserves in the world with 3 billion tons of B. Therefore, the toxicity of B is more important in Turkey. In this study, effective B removal was provided by different types of microalgae and then B recovery in culture media by bio-mining was detected. The water of Lake Mogan in Gölbaşı/Ankara/Turkey was used as the microalgae culture medium as a cost-reducing factor. The effects of light, temperature, NaNO₃ and K₂HPO₄ stresses on B removal were determined. The highest B removal was 17.19% at 25 μmol/m²s light intensity and 25 °C for Phormidium animale in Lake Mogan culture medium. Boron removal of Scenedesmus sp. was 36.42% at 25 μmol/m²s light intensity, at 25 °C, at 1.5 g/L NaNO₃ and 40 mg/L K₂HPO₄ concentrations in BG11 medium on the 15th day. The chl (a + b) concentration of Scenedesmus sp. was 1.63 μg/mL at 75 μmol/m²s light intensity and the chl (a) concentration of P. animale was 2.01 μg/mL at 25 μmol/m²s light intensity. Considering all parameters, Scenedesmus sp. and P. animale are recommended as effective biomaterials for the B removal process.