抗菌乳的制备及其初步纯化

Preparation and primary purification of antibacterial milk

确定了木瓜蛋白酶酶解乳蛋白所得抗菌乳对不同菌抗菌效果最佳时的酶解条件。最佳抑制金黄色葡萄球菌的酶解条件:pH值为6.0,温度为35℃,加酶量为1.9%,酶解时间90 min;最佳抑制大肠杆菌的酶解条件:pH值为6.0,温度为35℃,加酶量为2.5%,酶解时间30 min。比较了两种抗菌乳经离心、超滤后所制备的不同分子量多肽片断的抑菌效果。结果表明,分子量大于10 ku的多肽分子基本无抑菌作用;抑制金黄色葡萄球菌的多肽片段以分子量小于5 ku的多肽为主,而抑制大肠杆菌的多肽的分子量则集中在5～10 ku。

In this paper,we have gotten the optimum condition to prepare antibacterial milk with papain emymolysis for inhibiting different bacterium. The optimum condition to prepare antibacterial milk inhibiting Staphylococcusaureus was：pH=6.0, temperature 35℃, papain ratio 1.9%, time 90min,and inhibiting Escherichia coli was：pH=6.0, temperature 35℃, papain ratio 2.5%, time 30min. The antibacterial effects of different polypeptides,by centrifugation and ultrafiltration fi：om antibacterial milk,were compared. The results showed that the molecular weight of peptides having more than 10 ku had uncompicuous antibacterial effects, the polypeptide segments that inhibiting Staphylococ- cusaureus had a molecular weight mainly less than 5 ku, and the molecular weight of polypeptides inhibiting Escherichia coli was between 5 ku and 10 ku.