Synergistic influence of iodine and hydrogen peroxide towards the degradation of harmful algal bloom of Microcystis aeruginosa

Cyanobacterial blooming due to the influence of temperature and increased nutrients in ponds/lakes aided by the runoff from agricultural lands, is a serious environmental issue. The presence of cyanotoxins in water may poison the health of aquatic organisms, animals, and humans. In this study, we focus on chemical assisted degradation of Microcystis aeruginosa- an alga that is of special relevance owing to its consistent blooming, especially in tropical regions. The study aims to ascertain the individual iodine (I) and hydrogen peroxide (H2O2) and their combination (hereinafter referred to as IH) effects on the degradation of Microcystis aeruginosa. As expected, the collected pond water revealed the presence of metal ions viz., Ni, Zn, Pb, Cu and Mn, which enriched the blooming of M. aeruginosa. Interestingly, a complete rupture of the cells - pigment loss, biochemical degradation and oxidative damage-was observed by the IH solution after exposure for-9 h under ambient conditions. In comparison to control (original water without chemicals), the addition IH completely eliminated the pigments phycocyanin (99.5%) and allophycocyanin (98%), and degraded-81% and 91% of carbohydrates and proteins, respectively due to the synergistic action of I and H. Superior degradation of algae through a simple and eco-friendly approach presented in this study could be explored more effectively towards its large-scale applicability.

Automated summary

Cyanobacterial blooming caused by temperature and nutrient changes in ponds/lakes with agricultural runoff is a serious issue. The toxins in cyanobacteria can harm aquatic organisms, animals, and humans. This study focuses on using iodine and hydrogen peroxide, alone or in combination, to degrade Microcystis aeruginosa, which is known for its consistent blooming. The results showed that the IH solution completely destroyed the cells of M. aeruginosa, leading to pigment loss, biochemical degradation, and oxidative damage. It removed nearly all phycocyanin and allophycocyanin, as well as a significant amount of carbohydrates and proteins.