Bioremediation of Contaminated Water: The Potential of Aquatic Plants Ceratophyllum demersum and Pistia stratiotes Against Toxic Bloom

Toxic cyanobacteria, including <i>Microcystis</i>, produce harmful toxins that affect aquatic ecosystems and human health. Biotreatment using macrophytes shows promise in mitigating these blooms. This study investigates the bioaccumulation dynamics and biochemical responses of two aquatic macrophytes, <i>Pistia stratiotes</i> and <i>Ceratophyllum demersum</i>, in removing microcystin from contaminated water. <i>P. stratiotes</i> showed high initial bioaccumulation rates with rapid microcystin uptake, which is effective for short-term bioremediation. <i>C. demersum</i> has shown stable bioaccumulation. Biochemical analyses have revealed the activation of plant antioxidant defenses, with both macrophytes showing an increase in carotenoids, glutathione (GSH), and antioxidant enzymes such as superoxide dismutase (SOD) and glutathione-S-transferase (GST) concentrations. In particular, <i>C. demersum</i> has maintained higher antioxidant levels, contributing to its sustained capacity and resilience. Fluctuations in malondialdehyde (MDA) indicated oxidative stress, with <i>P. stratiotes</i> managing such stress through its defenses. Principal Component Analysis (PCA) supports these findings: Pistia's first two components explained 25.09% and 20.71% of the variance, with Carotenoid and Chl contributing strongly to PC1, and MDA and GST influencing both components. For <i>C. demersum</i>, PC1 and PC2 explained 21.79% and 19.78% of the variance, with Carotenoid and Chl a being major contributors, while SOD and GSH played significant roles in sample differentiation. Integrating both plants into bioremediation strategies could optimize microcystin removal: <i>P. stratiotes</i> offers rapid initial detoxification, while <i>C. demersum</i> ensures continuous, long-term remediation. This combined approach enhances the efficiency and sustainability of phytoremediation. Future research should optimize environmental conditions and explore synergistic effects among multiple plant species for more effective and sustainable bioremediation solutions.