FORMULASI SEDIAAN SABUN PADAT MINYAK ATSIRI SERAI DAPUR (Cymbopogon citratus DC.) SEBAGAI ANTIBAKTERI TERHADAP Escherichia coli DAN Staphylococcus aureus

Essential oil of lemongrass (Cymbopogon citratus DC.) was able to be used as an alternative to synthetic antibacterial in producing of transparent solid soap. The aim of this research is to study of lemongrass as antibacterial against Escherichia coli and Staphylococcus aureus, best formulation of lemongrass essential oil as antibacterial soap, and SNI quality standard of antibacterial soap. The study consisted of 5 formulas and 3 replications. The formula in this study was the addition of lemongrass essential oil of 0, 1, 2, 3, and 5 g. The antibacterial activity test against E. coli and S. aureus was done by diffusion well method, while the soap quality test determined was moisture content, the amount of saponified fatty acid, free fatty acids / alkali, unsaponified lipid, and mineral oil. The results shows that the addition of essential oil of lemongrass on transparent soap had a significant effect on antibacterial activity against E. coli, but did not affect to S. aureus. The best treatment in this research was the addition of essential oil of lemongrass 1 g (formula 2). Essential oils can inhibit the growth of E. coli and S. aureus with strong inhibition. The inhibitory zone towards E. coli was 12.25; 12.25; and 16.75 mm at concentration 25; 50; and 100% respectively, while that towards S. aureus was 10.25; 10.50; and 11.00 mm at the same concentration. The antibacterial activity of transparent soap against E. coli and S. aureus bacteria was also quite strong with both inhibitory diameter of 17-22 mm. The result of transparent solid soap quality test was in accordance with SNI standard except unsaponified fraction. Keywords: antibacterial, Cymbopogon citratus DC., Escherichia coli, soap, Staphylococcus aureus.