中文摘要：

研究了来自青海省发酵乳制品的45株乳酸菌对常见病原菌的抑制作用.通过排除有机酸和过氧化氢实验,菌株QHH7的上清液对指示菌仍有抑制作用;用蛋白酶处理后,发酵菌液的抑菌活性降低,因此确定其所产的抑菌物质具有蛋白质活性,是一种细菌素.菌株QHH7既能抑制G＋又能抑制G-菌,所以其产生的抑菌素是一种广谱细菌素.该种细菌素在100℃和pH值为2.0～10.0条件下分别处理30 min和2h后仍具有活性,但在pH值为8.0以上条件下处理2h,活性急剧下降.通过生理生化分析和16S rRNA基因序列分析,菌株QHH7被鉴定为Leuconostoc mesenteroides.菌株QHH7所产细菌素在100℃热稳定性良好,易被人体蛋白酶降解,而且QHH7来自传统发酵乳制品,因此其产生的细菌素具有一定的食品安全性.

英文摘要：

The ability of inhibiting growth of common pathogenic bacteria displayed by 45 lactic acid bacteria strains, isolated from fermentation dairy of Qinghai province, was surveyed in this paper. The supematant of QFIH7 strain could inhibit the growth of indicator strains excluded hydrogen peroxide and organic acid, while the inhibitive activity decreased after treatment with pepsin, which indicated that this inhibitory material had the features of protein and it could be classed as bacteriocin. QHH7 can both inhibit the growth of G＋ and G- strains, so its bac- teriocin was a broad spectrum one. After placed in 100 ℃ bath water for 30 minutes or at pH from 2.0 to 10.0 for 2 hours, bacteriocin still owned inhibitive activity, however, the inhibitive activity fell sharply under conditions of pH 8 or pH value higher than 8 for 2 hours. Ac- cording to results of physiology, biochemistry and 16S rRNA gene sequencing, QHH7 strain belongs to Leuconostoc mesenteroides. Bacteriocin yielded by QHH7 had good stability at 100 ℃ and can be degraded by pepsin of human beings and the source ensured its food safety.