Development of Bacterial Cocktail of Strains Staphylococcus hominis, Staphylococcus warneri, Bacillus subtilis, and Micrococcus luteus as active ingredients for Skin Care Formula

The microbial-based skin health care products that balance one's skin microbiome mimicking healthy skin are rapidly growing. Postbiotics gain more advantages in safety, shelf life, active peptides, and other active compounds such as GABA, which benefit human skin. We have isolated skin commensal bacteria, i.e., Staphylococcus hominis MBF12-19J, Staphylococcus warneri MBF02-19J, Micrococcus luteus MBF05-19J and Bacillus subtilis MBF10-19J in our previous study. This study aimed to make a formula of bacterial cocktail (BC) of those strains, elevate the BC formula into a ferment lysate (FL), and characterize the activities and test for skin sensitivity. The antibacterial activity was done by conducting a competition test using Propionibacterium acnes as an indicator bacterium, whereas the antioxidant activity assay was carried out using the DPPH method. The skin sensitivity was tested using the patch test method. The BC was lyzed by optimizing the enzymatic and ultrasonication methods, whereas sucrose was added as lyoprotectant to obtain a stable powder FL. Potential activity to inhibit P. acnes growth was achieved by a formula of FL consisting of M. luteus MBF05-19J: B. subtilis MBF10-19J: S. warneri MBF02-19J: S. hominis MBF12-19J in a ratio 1.5:1.5:0.5:0.5 or equivalent to DNA copy number/mL 1.01E+16: 1.14E+24: 1.96E+22: 1.50E+18. Skin sensitivity test results showed no sensitivity reaction, guaranteeing that CFS and FL are safe to use for the skin. Sucrose-FL at 12% sucrose formula showed higher physical stability than those without. However, the result of potential antioxidants showed mild and very mild activities compared to standard ascorbic acid.