Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i>
ε-Polylysine (ε-PL) is a cationic antimicrobial peptide, which easily forms complexes with food polyanions to weaken its antibacterial activity. A whey protein-ε-PL complex delivery system was found to be able to solve this problem. This study investigated the antimicrobial activity of the complexes...
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MDPI AG
2022-08-01
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| Series: | Foods |
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| Online Access: | https://www.mdpi.com/2304-8158/11/15/2311 |
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| author | Yuecheng Meng Li Lou Zhipeng Shao Jie Chen Yanhua Li Tianqi Zhang |
| author_facet | Yuecheng Meng Li Lou Zhipeng Shao Jie Chen Yanhua Li Tianqi Zhang |
| author_sort | Yuecheng Meng |
| collection | DOAJ |
| description | ε-Polylysine (ε-PL) is a cationic antimicrobial peptide, which easily forms complexes with food polyanions to weaken its antibacterial activity. A whey protein-ε-PL complex delivery system was found to be able to solve this problem. This study investigated the antimicrobial activity of the complexes and their mechanism against Gram-positive bacteria. The minimal inhibitory concentration of the complexes with different ε-PL contents against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> were 19.53–31.26 and 3.90–7.81 μg/mL, respectively, which were similar to free ε-PL. Furthermore, the whey protein-ε-PL complexes had a strong bactericidal effect on <i>Bacillus subtilis</i>. The inhibition zone diameters of the complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> containing 5000 μg/mL of ε-PL were 14.14 and 16.69 mm, respectively. The results of scanning electron microscopy showed that the complexes could destroy the cell membrane structure in <i>Bacillus</i><i>subtilis</i>, resulting in holes on the surface, but not in <i>Staphylococcus aureus</i>. The results of molecular dynamics simulation showed that under electrostatic interaction, the complexes captured the phospholipid molecules of the bacterial membrane through the hydrogen bonds. Parts of the ε-PL molecules of the complexes were embedded in the bilayer membrane, and parts of the ε-PL molecules could penetrate the bilayer membrane and enter the bacterial internal environment, forming holes on the surface of the bacteria. The antibacterial results in fresh meat showed that the whey protein-ε-PL complexes could reduce the total mesophilic and <i>Staphylococcus aureus</i> counts. This study on the antibacterial activity mechanism of whey protein-ε-PL complexes could provide a reference for the application of ε-PL in protein food matrices. |
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| language | English |
| last_indexed | 2024-03-09T05:24:42Z |
| publishDate | 2022-08-01 |
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| series | Foods |
| spelling | doaj.art-cbdfc33c75674fc7b6a84eff15bb9c6b2023-12-03T12:37:43ZengMDPI AGFoods2304-81582022-08-011115231110.3390/foods11152311Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i>Yuecheng Meng0Li Lou1Zhipeng Shao2Jie Chen3Yanhua Li4Tianqi Zhang5School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, ChinaSchool of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, ChinaResearch and Development Center, Wuxi Biortus Biosciences Co., Ltd., Jiangyin 214437, ChinaSchool of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, ChinaSchool of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, ChinaSchool of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, Chinaε-Polylysine (ε-PL) is a cationic antimicrobial peptide, which easily forms complexes with food polyanions to weaken its antibacterial activity. A whey protein-ε-PL complex delivery system was found to be able to solve this problem. This study investigated the antimicrobial activity of the complexes and their mechanism against Gram-positive bacteria. The minimal inhibitory concentration of the complexes with different ε-PL contents against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> were 19.53–31.26 and 3.90–7.81 μg/mL, respectively, which were similar to free ε-PL. Furthermore, the whey protein-ε-PL complexes had a strong bactericidal effect on <i>Bacillus subtilis</i>. The inhibition zone diameters of the complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> containing 5000 μg/mL of ε-PL were 14.14 and 16.69 mm, respectively. The results of scanning electron microscopy showed that the complexes could destroy the cell membrane structure in <i>Bacillus</i><i>subtilis</i>, resulting in holes on the surface, but not in <i>Staphylococcus aureus</i>. The results of molecular dynamics simulation showed that under electrostatic interaction, the complexes captured the phospholipid molecules of the bacterial membrane through the hydrogen bonds. Parts of the ε-PL molecules of the complexes were embedded in the bilayer membrane, and parts of the ε-PL molecules could penetrate the bilayer membrane and enter the bacterial internal environment, forming holes on the surface of the bacteria. The antibacterial results in fresh meat showed that the whey protein-ε-PL complexes could reduce the total mesophilic and <i>Staphylococcus aureus</i> counts. This study on the antibacterial activity mechanism of whey protein-ε-PL complexes could provide a reference for the application of ε-PL in protein food matrices.https://www.mdpi.com/2304-8158/11/15/2311whey protein-ε-polylysine complexesGram-positive bacteriaantibacterial activityantibacterial mechanism |
| spellingShingle | Yuecheng Meng Li Lou Zhipeng Shao Jie Chen Yanhua Li Tianqi Zhang Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> Foods whey protein-ε-polylysine complexes Gram-positive bacteria antibacterial activity antibacterial mechanism |
| title | Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> |
| title_full | Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> |
| title_fullStr | Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> |
| title_full_unstemmed | Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> |
| title_short | Antibacterial Activity and Mechanism of Action of Whey Protein-ε-Polylysine Complexes against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i> |
| title_sort | antibacterial activity and mechanism of action of whey protein ε polylysine complexes against i staphylococcus aureus i and i bacillus subtilis i |
| topic | whey protein-ε-polylysine complexes Gram-positive bacteria antibacterial activity antibacterial mechanism |
| url | https://www.mdpi.com/2304-8158/11/15/2311 |
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