Eco-Friendly Novel Algicidal Efficiency of Streptomyces eurocidicus JXJ-0089 Against Harmful Algal Bloom of Microcystis aeruginosa MDEG1

Cyanobacterial harmful algal blooms occur worldwide and cause deleterious effects on freshwater or marine ecosystems and public health. Cyanobacterial algal blooms create and release toxic odorous chemicals that are really dangerous to the biodiversity of aquatic ecosystems and the drinking water supply. The biological regulation of toxic algal blooms is essential to economic growth, protection of the environment, and promotion of human health. Treatment of the El-Manzala Lake strain of Microcystis aeruginosa MDEG1 (Damietta, Egypt) with Streptomyces eurocidicus JXJ-0089 induced an active algicidal effect and disrupted the antioxidant systems. The data revealed a significant decrease in photosynthetic pigment content (chlorophyll a, carotenoid, C-phycocyanin, allophycocyanin, phycoerythrin, and total phycobiliprotein), size of chloroplasts, photosynthetic efficiency, total carbohydrate, total soluble protein, and total algal biomass production. In this study, the effect of S. eurocidicus treatment on the physiological properties of M. aeruginosa, such as ROS cellular redox status using flow cytometry technique, transmission electron microscopy technologies, was estimated to investigate the ultrastructural of the cell morphology, the oxidative damage indicator malondialdehyde, and the activities of antioxidant enzymes of SOD, CAT, and POD. The main manifestations were the induction of oxidative stress, increasing ROS formation, an impaired cell membrane structure, damage to the cell membrane structure, and potentially disrupting its barrier function leading to cellular damage. These findings suggest that S. aeruginosa has the potential to be used as an eco-friendly biological control agent for managing harmful effects of M. aeruginosa cyanobacterial blooms, particularly in water treatment processes.