Anti-Microbial Activities of Sea Lettuce, Ulva rigida, Extracts Against Pathogenic Microorganisms

The aim of this study was to determine the antibacterial properties of the green macroalgae Ulva rigida, which was both genetically and morphologically identified and cultivated under laboratory conditions. The study focused on its effects on Gram-positive microorganisms, including Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, and Bacillus subtilis ATCC 6633, as well as Gram-negative microorganisms, such as Escherichia coli ATCC 25922, Salmonella enterica ATCC 13311, and Pseudomonas aeruginosa ATCC 27853. Through the use of disc diffusion and micro-dilution methods, the antibacterial properties of Ulva were scrutinized in regards to both Gram-positive/negative bacteria. Except hexane extracts of Ulva, the other four solvent (acetone, diethyl ether, ethanol, and methanol) extracts of Ulva showed antimicrobial activities on all bacteria types.