Influence of TiO2Nanoparticles on Growth and Phenolic Compounds Production in Photosynthetic Microorganisms

Abstract

The influence of titanium dioxide nanoparticles (pure anatase and 15% N doped anatase) on the growth ofChlorella vulgaris,Haematococcus pluvialis, andArthrospira platensiswas investigated. Results showed that pure anatase can lead to a significant growth inhibition ofC. vulgarisandA. platensis(17.0 and 74.1%, resp.), while forH. pluvialisthe nanoparticles do not cause a significant inhibition. Since in these stress conditions photosynthetic microorganisms can produce antioxidant compounds in order to prevent cell damages, we evaluated the polyphenols content either inside the cells or released in the medium. Although results did not show a significant difference inC. vulgaris, the phenolic concentrations of two other microorganisms were statistically affected by the presence of titanium dioxide. In particular, 15% N doped anatase resulted in a higher production of extracellular antioxidant compounds, reaching the concentration of 65.2 and68.0 mg gDB-1forH. pluvialisandA. platensis, respectively.