Synthesis of chitosan nanoparticles as a method to regulate cyanobacterial abundance in aquatic environments

Cyanobacterial blooms are a result of eutrophic environments and can cause harm to the health of water bodies. Chitosan nanoparticles (CSNPs) have previously been used for controlling the growth of bacteria. The objective of this research was to determine if chitosan nanoparticles could be used as a natural method for cyanobacterial management. To test this, CSNPs were synthesized using the ionic gelation method, which involves dissolving chitosan and adding a crosslinker into the solution. Flocculation and growth inhibition testing was conducted on Anabaena cyanobacteria cultures, which were tested with and without the addition of CSNPs. The CSNPs were effective in flocculating cyanobacteria, and visible flocs were noticed immediately after the addition of CSNPs. The CSNPs also prevented the growth of the cyanobacteria, as fluorescence in the experimental cultures decreased after two days while it increased in the control cultures. The success of CSNPs against cyanobacteria is likely due to the electrostatic interactions that occur between the surface of the nanoparticles and the surface of the cyanobacterial cells. These interactions result in the disruption of the bacterial cell wall, and can cause the cells to clump together, forming flocs. In conclusion, CSNPs displayed promising results to manage the growth of cyanobacteria.