Influence of chitosan-based carbon dots added in MgAC-containing culture medium on green alga Tetraselmis sp.

Abstract

The aim of this study was to evaluate the growth-promoting effects of the combination of magnesium aminoclay (MgAC) and amino-functionalized carbon dots (N(CD)s) on Tetraselmis sp. cultures with an emphasis on N(CD)s. To that end, simply sol-gel-synthesized MgAC and one-pot carbonization-synthesized N(CD)s were utilized. The as-prepared N(CD)s possessed the expected amino-functional groups, exhibited strong blue emission with bright luminescence, and showed a quantum yield (QY) of 5.69%. The maximum specific growth rate and biomass productivity were achieved with the combination of 0.1 g L−1 MgAC and 40 μg mL−1 N(CD)s, which afforded improvements in lipid and protein accumulation relative to the control, whereas carbohydrate accumulation slightly decreased. At low concentrations (0.1 g L−1), MgAC demonstrated growth stimulation. The N(CD) addition to the MgAC-containing medium further supported the Tetraselmis sp. cultures in counteracting the effects of UV radiation and in improving photosynthesis activity. In these ways, increased growth and biomass productivity under UV irradiation and enhanced pigment contents under the light-irradiance condition were obtained. Therefore, use of the MgAC-N(CD) combination as a culture-medium supplement is a promising method for microalgae biorefinery applications.