Research Summary
Human skin is a complex ecosystem and is host to a large number of microorganisms. When the bacterial ecosystem is balanced and differentiated, the skin remains healthy. However, the use of cosmetics can alter this balance and promote the appearance of skin diseases. Some microorganisms on the skin can utilize certain cosmetic components, which either promote their growth or produce metabolites that influence the skin environment.
In this study, we tested the ability of the *Malassezia* species and some bacterial strains to assimilate substances frequently used in dermal formulations. The growth capability of microorganisms was determined, and their lipase activity was analyzed. The growth of all *Malassezia* species in the presence of free acids, free acid esters, and fatty alcohols with a fatty chain length of more than 12 carbon atoms was observed. No growth was observed in the presence of fatty alcohol ethers, secondary fatty alcohols, paraffin- and silicon-based substances, polymers, polyethylene glycols, quaternary ammonium salts, hydroxy fatty acid esters, or fatty acids and fatty acid esters with a fatty chain length shorter than 12 carbon atoms.
The hydrolysis of esters by *Malassezia* lipases was detected using High Performance Thin Layer Chromatography (HPTLC). The production of free fatty acids as well as fatty alcohols was observed. Growth promotion or inhibition of bacterial strains was only found in the presence of a few ingredients. Based on these results, formulations containing microbiome-inert ingredients were developed.
Keywords: *Malassezia* spp.; *Staphylococcus* spp.; *Corynebacterium* spp.; lipases; cosmetics
<Access the full report below>