Utilization of miroalgae Spirulina platensis as anti-bacterial compound in soap

Antibacterial soap is the best-selling soap in Indonesia as a cleaning agent. Unfortunately, since United States Food and Drug Administration (FDA) posted an article about antibacterial compound danger in soap, antibacterial soap has some issue due to its danger for long and short-term used dangerous effect. However, anti-bacterial soap is still needed in places with high levels of bacterial spread, such as hospitals. To solve this problem, safe antibacterial compounds are needed. Microalgae Spirulina platensis is one of microalgae that contains safe anti-bacterial compound. In addition, these types of microalgae have other compounds that are very beneficial for skin, for example anti-aging and anti-oxidant. Besides the ingredients, the form of soap also needs to be considered to avoid bacterial contamination. The form of soap with a thin layer is the right form to solve this problem. This research aims to obtain optimal NaOH concentration as alkali in antibacterial soap with microalgae S. platensis. NaOH concentration that will be used are 3.75, 5.5, 6.25, and 8,75 M. Based on result of quality test, the best NaOH concentration to use is 3.75 M with 0.478% of free fatty acid and 14.03% of water. With using this concentration, there are no bacterial growth until 25% dilution of sample.