Investigation of the antibacterial activity against Cutibacterium acnes of lysozyme pu-rified from “Co Co” duck egg whites

Abstract

Lysozyme has been applied in various fields such as food technology, medicine, and diagnostics because it can resist many types of bacteria. In this research, lysozyme from duck egg whites was studied to evaluate the antibacterial activity against Cutibacterium acnes (C. acnes) often causing acne on human skin. Lysozyme was purified from duck egg whites by ion-exchange chromatography and gel-filtration chromatography. After that, this enzyme was used to investigate the resistance to C. acnes at different pH, temperature, concentration, and storage conditions. The results presented that lysozyme exhibited the best resistance to C. acnes at pH 6.0 and 6.5 on trypticase - yeast extract - heart extract - glycerol agar (TYEG) medium, at 30°C and 35°C. Additionally, these conditions had the least effect on lysozyme antibacterial activity. The minimal inhibitory concentration (MIC80) and minimum bactericidal concentration (MBC) of lysozyme to C. acnes were 0.55 mg/mL and 1.11 mg/mL, respectively. Lysozyme could keep up the best antimicrobial activity when stored at -20oC and -10oC; After 30 days, it still kept nearly 80% of its activity. These findings will offer a basis for larger-scale production of lysozyme powder for further research and commercial purposes, especially skin-care products.