Synthesis of zinc oxide nanoparticles mediated by Dictyota dichotoma endophytic fungi and its photocatalytic degradation of fast green dye and antibacterial applications

•Seaweed was collected from Ramanathapuram coastal area and the endophytic fungus was isolated.•ZnO nanoparticle was synthesized by utilizing extra cellular products of fungal endophytes is not yet predicted.•ZnONPs show the high efficacy of antimicrobial and antibiofilm activity.•Excellent photocatalytic dye degradation was observed in the ZnO NPs treated samples.