Renewal of nanofibers in Chlorella fusca microalgae cultivation to increase CO2 fixation

This study explored strategies to increase the CO2 fixation ability of microalgae by renewing polymeric nanofibers in cultures of Chlorella fusca LEB 111. Nanofibers composed of 10% (w v(-1)) polyacrylonitrile (PAN)/dimethylformamide (DMF) containing 4% (w v(-1)) iron oxide nanoparticles (NPsFe(2)O(3)) were added to photobioreactors. The nanomaterial was renewed in the test cultures as follows: renewal only on day 7; renewal only on day 15; or renewal on both days 7 and 15 (i.e., double renewal). The highest biomass concentration (2.53 g L-1) and CO2 biofixation rate (141.5 mg L-1 d(-1)) were obtained by cultivating with double renewal, resulting in values 21.6% and 23% higher, respectively, than those obtained by cultivation without renewal. The application of nanofiber renewal in the cultivation of C. fusca LEB 111 shows the potential to increase CO2 biofixation, which may contribute to reducing the atmospheric concentrations of this main greenhouse gas intensifier.