Cancer is a threatening disease that needs strong therapy with fewer side effects. A lot of different types of chemotherapy or chemo-drugs are used in cancer treatments but have many side effects. The increasing number of antibiotic-resistant microorganisms requires more study of new antimicrobial compounds and delivery and targeting strategies. This work aims to isolate and identify sp., and extract alginate from sp. As well as fabricating selenium nanoparticles using ascorbic acid as reducing agent (As/Se-NPs), and loading extracted alginate with selenium nanoparticles (Alg-Se-NCMs). The As/Se-NPs and Alg-Se-NCMs were categorized by TEM, EDX, UV-Vis spectrophotometry, FT-IR, and zeta potential. The antifungal activities of both As/Se-NPs and Alg-Se-NCMs were investigated against some human pathogen fungi that cause skin infection such as (RCMB 002005), (RCMB 002008), (RCMB 0049001), (RCMB 005003), and (RCMB 001002). The anticancer activities were determined against HCT-116 colorectal cancer and Hep G2 human liver cancer cells. UV spectra of As/Se-NPs and Alg-Se-NCMs confirmed a surface plasmon resonance at 269 and 296 nm, and zeta potential has negative charges -37.2 and -38.7 mV,. Both As/Se-NPs and Alg-Se-NCMs were hexagonal, size ranging from 16.52 to 97.06 and 17.29 to 44.2. Alg-Se-NCMs had anticancer activities against HCT-116 and HepG2. The Alg-Se-NCMs possessed the highest antifungal activities against , followed by , but did not possess any activities against . Alginate-capped selenium nanoparticles can be used as antifungal and anticancer treatments.