Effects on photosynthetic and antioxidant systems of harmful cyanobacteria by nanocrystalline Zn-MOF-FA

Highlights: • MOFs synthesized with doped allelochemical (ferulic acid) were effective in inhibiting algae. • The synergistic effect of Zn²⁺ and ferulic acid can effectively inhibit the growth of algae. • Zn-MOF-FA can effectively inhibit photosynthesis in algae by blocking electron transfer. • Zn-MOF-FA can effectively damage the antioxidant system of algae. Metal-organic frameworks (MOFs) constitute new class of materials recently used by researchers in the field of controlling cyanobacteria. However, the use of MOFs in combination with allelochemicals for cyanobacteria inhibition had not been investigated before. The present study is aimed towards the investigation of the effect and mechanism of cyanobacteria inhibition by combining MOF with allelochemical (ferulic acid, FA) for the first time. In this study, the results showed that the synergistic effect of Zn²⁺ and FA from Zn-MOF-FA could inhibit cyanobacteria to a greater extent than the corresponding dosage of Zn²⁺ and FA. The inhibition ratio of Microcystis aeruginosa has been found to be more than 50% when the Zn-MOF-FA concentration exceeds 2 mg·L⁻¹ after four days exposure. Zn-MOF-FA at 1 mg·L⁻¹ did not completely inhibit M. aeruginosa, and the inhibition effect has been of only temporary type. The inhibitory effect of Zn-MOF-FA on algae has mainly been attributed to the hindrance of electron transfer and energy capture in the photosynthetic system and the oxidative damage caused by reactive oxygen species (ROS).