<![CDATA[Used cooking oil can be turned into liquid soap by saponification, but soap made only from oil and KOH contains no added antibacterial agent. This study aimed to analyze the antibacterial activity of used cooking oil-based liquid soap with added lemongrass (Cymbopogon citratus) against Escherichia coli and Staphylococcus aureus. A laboratory experiment with a completely randomized design used four formulations: F0 (no lemongrass), F1 (1%), F2 (2%), and F3 (3%). Activity was tested by well diffusion, with chloramphenicol and distilled water as positive and negative controls and pure lemongrass essential oil as a comparison; inhibition zones (mm) were measured in triplicate. All formulations inhibited E. coli, with mean zones increasing from 4.95 ± 0.80 mm (F0, weak) to 6.13 ± 0.5 mm (F3, moderate), indicating a dose-response pattern. Against S. aureus, all formulations showed only weak activity (3.03–3.83 mm) without a clear concentration trend. The soap base alone showed some inhibition, and responses differed between bacteria, possibly because of interactions between surfactants and lemongrass essential oil in the soap matrix.]]>
Copyrights © 2026
