Investigating the Potential of Engineered Nano-Enabled Microalgae System to Enhance Simultaneous Phycoremediation of 2-Nitroaniline and Carbon Sequestration

Abstract

Microalgae, particularly Chlorella vulgaris (CV), have gained increasing attention for their role in bioremediation and carbon sequestration due to their high photosynthetic efficiency, rapid biomass production, and ability to mitigate environmental contaminants. This study investigates the potential of an engineered nanoenabled microalgal system to enhance the simultaneous degradation of 2-nitroaniline (2-NA), a persistent nitroaromatic pollutant, and carbon sequestration under the influence of titanium dioxide nanoparticles (TiO₂ NPs). The experimental approach assessed the effects of TiO₂ NPs on CV growth kinetics, photosynthetic pigment synthesis, and CO₂ fixation rates while analyzing the degradation efficiency of 2-NA. Results revealed that 20 mg L^–1 TiO₂ NPs optimized algal growth and photosynthetic activity, leading to a 37.4% increase in biomass productivity and enhanced CO₂ sequestration rates compared to control. Extensive characterization including Raman and Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed TiO₂ NP interactions with algal cellular components, demonstrating maintained structural integrity and biocompatibility. However, coexposure to 2-NA induced oxidative stress, evidenced by significant upregulation of catalase (CAT) and superoxide dismutase (SOD) activities, indicating a defensive response. The TiO₂-integrated CV system demonstrated a 59.8% degradation efficiency of 2-NA at 10 mg L^–1, surpassing biological degradation alone (39%). These findings underscore the dual benefits of integrating nanotechnology with microalgal systems for environmental remediation, offering a circular bioeconomy approach that couples wastewater treatment with carbon capture.