Abstract:A strain Aspergillus terreus PZ-8 was isolated from the marine sediments in Lincheng，Zhoushan，China.A one strain many compounds（OSMAC）strategy was adopted to systematically analyze the influences of three salinity gradients（0.1%，3.0%，and 5.0%）on the diversity，abundance，and in vitro bioactivity of secondary metabolites produced by A.terreus PZ-8.The results showed that salt stress significantly altered the diversity and abundance of secondary metabolites.Ethyl acetate extracts（EA-0.1，EA-3，and EA-5）at a concentration of 0.5 mg/mL exhibited the DPPH and ABTS+ radical scavenging rates over 90%.Further bioactivity assays demonstrated that EA extracts were more effective against Gram-positive bacteria（Staphylococcus aureus）than against Gram-negative bacteria，significantly inhibited the biofilm formation of S.aureus，and reduced the production of biofilm-associated substances such as polysaccharides and proteins.Furthermore，scanning electron microscopy revealed that EA-3 and EA-5 significantly disrupted the integrity of S.aureus cell membranes at 2×minimal inhibitory concentration（MIC）.Additionally，the brine shrimp lethality assay indicated that brine shrimp exposed to EA-0.1，EA-3，and EA-5 at MIC exhibited the relative survival rates of 81.7%，91.7%，and 88.3%，respectively.The IC50 values of EA-0.1，EA-3，and EA-5 were 222.7，753.4 μg/mL，and 504.0 μg/mL，respectively，suggesting low cytotoxicity.In summary，the OSMAC strategy unlocked the abundance and biodiversity of secondary metabolites in A.terreus PZ-8 and the natural，safe，and efficient secondary metabolites with significant antioxidant，antibacterial，and anti-biofilm activities and the potential of serving as eco-friendly food preservatives.