The development of sustainable biomaterials with antifungal properties is an important objective in agricultural, environmental, and materials biotechnology. Chitinases, enzymes that hydrolyze chitin in fungal cell walls, are attractive eco‑friendly biocontrol candidates; however, their industrial application is often limited by low heterologous yields and costly purification. In this study, a Generally Recognized As Safe (GRAS) yeast strain (Saccharomyces cerevisiae Y2805) was engineered to secrete a chitinase (Chit36) from Trichoderma atroviride using an optimized extracellular production system incorporating a plant‑derived signal peptide. This design enabled direct use of culture filtrates without downstream purification, thereby reducing process complexity and potential environmental burden. The recombinant filtrates showed strong chitinolytic activity and significantly inhibited the growth of multiple species of plant and opportunistic fungal pathogens in standardized plate‑ and broth‑based assays relative to vector‑only controls. Time‑course microscopy revealed suppression of early hyphal elongation and germ‑tube abnormalities, resulting in delayed or aberrant colony development. Additional imaging indicated cell wall surface irregularities and localized swelling consistent with chitin degradation and impaired wall integrity. Together, these observations provide experimental evidence that the recombinant yeast platform produces bioactive materials with reproducible antifungal effects. Ongoing studies are assessing enzyme stability, broadening pathogen coverage, and evaluating formulation and storage conditions to define application‑relevant performance and constraints within sustainable antifungal strategies.