Introduction. Keratin hydrolysates have been shown to be effective in restoring hair structure, forming a protective film, and providing elasticity. Traditional chemical methods for producing keratin, however, are not environmentally friendly. A biotechnological approach using keratinolytic microorganisms presents a more sustainable alternative. Although several keratinase drugs are available on the market, only one is produced in Russia, by Biopreparat Trading House.

Purpose. This study aims to develop a biotechnological method for producing keratin hydrolysate using two newly isolated strains of Bacillus licheniformis, BAL-1 and BAL-2, and to assess its efficacy in a cosmetic hair serum formulation.

Materials and methods. Bacillus licheniformis strains BAL-1 and BAL-2 were used for the study. Chicken feathers with a moisture content of 75% were used as a source of keratin. SPEV and MDBK cell lines were employed for biotesting.

Cultivation was carried out on a modified medium with feather at 5 g/100 ml at 28°C and 80 rpm for 72 hours. The parameters were optimized to include temperature (20-40°C), stirring (80-160 rpm), feather content (5-20 g), and adding up to 8 g of urea to the nutrient medium. Keratinase activity was determined spectrophotometrically.

Results. Optimization of the conditions resulted in an increase in keratinase activity by 2.4 times, up to 39 KA/cm³ for BAL-1 and 44 KA/cm³ for BAL-2. The hydrolysate was safe for use on SPEV and MDBK cell lines, with cell viability ≥65%. The serum (containing 3% hydrolysate) improved hair condition in a focus group of 5 people over 2 months, with 100% reporting increased smoothness and 80% reporting elasticity and shine.

Conclusions. The developed method of enzymatic hydrolysis of feathers has been shown to be effective in creating a cosmetic ingredient, keratin hydrolysate. Future research will focus on identifying biologically active peptides in feather hydrolysate and assessing their potential contribution to the efficacy of cosmetic hair serums.

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