乳源抗菌肽的抑菌活性及其影响因素

Antibacterial activity and influential factors of milk-derived antimicrobial peptides

以大肠杆菌和金黄色葡萄球菌为实验菌,研究了乳源抗菌肽的抑菌活性,以及pH值、温度、热处理时间、胃蛋白酶水解和离子强度等不同因素对乳源抗菌肽抑菌活性的影响.结果表明:乳源抗菌肽对金黄色葡萄球菌的最小抑菌浓度为4μg/mL,对大肠杆菌的最小抑菌浓度为8μg/mL;乳源抗菌肽在pH值为7.0～8.0时的抑菌活性最高;在60℃以上时,随着温度的升高及加热时间的延长,乳源抗菌肽抑菌活性逐渐降低;胃蛋白酶能够部分水解乳源抗菌肽,降低乳源抗菌肽的抑菌活性;当NaCl浓度为0～100 mmol/L,CaCl2浓度为0～5.0 mmol/L时,离子强度越大,乳源抗菌肽的抑菌活性越低.

Considering pH,temperature,heat-treated time,pepsin hydrolysis,and ionic strength on the antibacterial activity of milk-derived antimicrobial peptides against Escherichia coli and Staphylococcus aureus,antibacterial activity and influence factors were investigated in this paper.The results show that the MIC of milk-derived antimicrobial peptides repressing S.aureus and E.coli is 4 μg/mL and 8 μg/mL respectively.The milk-derived antimicrobial peptides have best antibacterial activity at pH 7.0～8.0,and its antibacterial activity decreases with the increase of temperature when the heating time is above 60 ℃.Activities of antibacterial peptides obtained from milk decrease after treatment with pepsin.Antibacterial effectiveness reduces in presences of NaCl at concentration 0～100 mmol/L,CaCl2 at concentration 0～5.0 mmol/L.The antibacterial activities of milk-derived peptides decrease with the increase of ionic strength.