Abstract This research was conducted from February-June, 2023. Sampling of A. marina and S. alba mangroves was collected in the mangrove ecosystems of Mengkapan Village, Sungai Apit District, Siak Regency. This research intended to identify the species and test the antimicrobial activity of endophytic fungi found in the leaves and stems of A. marina and S. alba mangroves in the mangrove ecosys…