Immediate and long-term impacts of potassium permanganate on photosynthetic activity, survival and microcystin-LR release risk of Microcystis aeruginosa

► KMnO4 was effective on M. aeruginosa inactivation. ► The integrity of M. aeruginosa cells was preserved immediately after KMnO4 oxidation. ► Improper KMnO4 quantity induced microcystin-LR release in subsequent cultivation. ► Photosynthesis parameters are useful to predict the growth profile of M. aeruginosa.