从内蒙古传统乳制品酸马奶中筛选出1株产生具有广谱抑菌活性物质的嗜酸乳杆菌NX2-6。在排除酸性产物和过氧化氢的干扰后,菌株NX2-6所产生的类细菌素对金黄色葡萄球菌等革兰氏阳性菌和大肠杆菌等革兰氏阴性菌及米曲霉等真菌具有较强的抑制作用;经胰蛋白酶、胃蛋白酶、蛋白酶K处理后发酵液抑菌活性明显下降,但仍具有较强的抑菌活性,对α-胰凝乳蛋白酶抗菌活性没有显著变化,因此表明该抗菌活性物质为蛋白类物质或非单一物质。在酸性条件下它具有很好的热稳定性,pH2.0时活性最强,中性或碱性条件下不具有抗菌活性,抑菌活性pH值范围在2.0-5.0。此抗菌物质不同于一般细菌素,属于类细菌素,命名为Lactobacillin NX2-6。菌株NX2-6产物在生防、食品具有潜在的应用价值。

A strain,Lactobacillus acidophilus NX2-6,was isolated from Chigee,having ability of producing broad-spectrum antimicrobial substance.Precluding the effect of organic acids and hydrogen peroxide,the fermentation broth of strain NX2-6 exhibited significant inhibitory activity against gram-positive bacteria,such as Staphyloccous aureus;gram-negative bacteria such as Escherichia coli and fungi such as Aspergillus oryzae.After treated with trypsin,pepsin,protease K and α-chymotrypsin,it's antimicrobial substances inhibitory activity decreased sharply with all of them but α-chymotrypsin,which showed the antimicrobial substance might be a protein or a mixed substance.The antimicrobial substance showed good thermal stability in antimicrobial activity within the range pH 2.0-5.0,with the optimum activity at pH 2.0.So it indicated the antimicrobial substance,termed Lactobacillin NX2-6,belongs to a bacteriocin.The substance produced by strain NX2-6 was a promising cadidate applicable in the bio-control and food industries.