Mangroves represent highly diverse marine ecosystems, encompassing various vegetation such as shrubs, plants, trees, palms, and other plant forms that have adapted to thrive in both freshwater and saline environments. Within these mangrove ecosystems, secondary metabolites are present, contributing to various pharmacological functions and holding significant ecological importance. Endophytic fungi constitute a substantial and quantifiable portion of fungal biodiversity and are acknowledged for their impact on the composition and diversity of plant communities. This study aims to investigate the extracellular proteins and enzyme activity exhibited by endophytic fungi discovered in the leaves of Sonneratia alba mangroves collected in Buton, Southeast Sulawesi, Indonesia. The primary objective is to evaluate the compatibility of marine fungi with antibacterial and antioxidant activity. The research involves analyzing the biological activities of marine fungi containing cellulase enzyme through methods such as DNS for reducing sugar, protein concentration determination, antioxidant analysis, and total phenol content assessment. Sample A (shaker) has highest enzyme activity at Day 4 and Sample B has highest enzyme activity at Day 6 (static condition). The protein concentration in the purified cellulase from Aspergillus terreus surpassed that of crude enzyme extracts.