Utilization of the skin and environmental friendliness of sophorolipids in the development of sustainable home care products

While demand for safer products worldwide are increasing as consumers became more conscious of the health and environmental impacts of conventional cleaning agents, in Japan, natural products appeared as early as the 1970s as a measure against environmental issues. A few decades later, to solve skin and the environment issues caused by synthetic surfactants, the development and application of biosurfactants such as glycolipid-type sophorolipids (SLs), which are both safe for the skin and the environment, emerged and are used as alternatives.

To use SL in the development of home care products, cytotoxicity test and skin irritation test were performed to confirm its mildness to the skin. Biodegradability and aquatic toxicity tests in accordance with OECD guidelines were also checked to confirm its safety to the environment. 

The cytotoxicity and skin irritation induced by SL were extremely low (logIC ₅₀ = 4.76 mg/L) and equivalent to those of solvents and oils used in home care and personal care products. Biodegradability tests showed that after 28 days, the biodegradability of SL reached 100%, indicating that SL are readily biodegradable. For the aquatic toxicity tests, the EC₅₀ of SL >473 mg/L was found in P. subcapitata, LC₅₀ of 64.8 mg/L in O. latipes, EC₅₀ of 48.2 mg/L in D. magna, with aquatic surface tension of 39 mN/m in O. latipes and to 41 mN/m in D. magna, exhibiting SL has low cytotoxicity with surface activity.

The overall results showed that SL are suitable for home care applications as mild and eco-friendly alternatives; they are safe for both the user and for the environment.

References
1. Kumano et al. J. Oleo Science, 73, 1169-1175 (2024).
2. Kumano et al. J. Environ. Biol., 40, 595-600 (2019)