青海湖裸鲤肠道乳酸菌多样性与抑菌活性

Diversity and antimicrobial activity of intestinal lactic acid bacteria isolated from Gymnocypris przewalskii

摘要:

【目的】通过生理生化特性，结合16S rRNA基因序列分析研究青海湖裸鲤肠道乳酸菌分离株的多样性，并对这些代表株的抑菌活性进行初步探讨，以期筛选具有高效抑菌活性的鱼源益生菌。【方法】对分离的47株乳酸菌代表株进行pH、温度生长范围、耐盐性等生理生化特征检测，结合16S rRNA基因序列对已分离到的乳酸菌进行基因分型和菌种鉴定，采用牛津杯双层平板法检测乳酸菌代表株的抑菌活性。【结果】鉴定结果显示：23株为Lactobacillus fuchuensis (48.94%)，12株为Lactobacillus curvatus (25.53%)，3株为Leuconostoc fallax (6.38%)，2株为Lactobacillus sakei (4.26%)，2株为Weissella ceti (4.26%)；2株为Lactococcus cremoris (4.26%)，1株为Leuconostoc lactis (2.13%)，1株为Weissella minor (2.13%)，1株为Enterococcus devriesei (2.13%)。qz1217、qz1196、qz1220所在的A、B、C三组乳酸菌在5?50 °C的温度范围内生长良好，qz1196、qz1220所在的B、C组在pH 3.0?10.0的范围内生长良好，几乎所有乳酸菌都具有耐6.5%盐浓度特性。13株乳酸菌菌株对6种病原菌都具有抑制作用。通过排除酸、过氧化氢实验，发现上清液仍然具有抑菌活性。对qz1251发酵液进行蛋白酶处理，抑菌活性消失，确定其抑菌物质属于蛋白类物质，是一种细菌素。【结论】青海湖裸鲤肠道附着乳酸菌的多样性为益生性乳酸菌的筛选提供优质资源及数据参考。

Abstract:

[Objective] To understand the diversity and antimicrobial activity of intestinal lactic acid bacteria isolated from Gymnocypris przewalskii. [Methods] We identified 47 lactic acid bacteria by the physiological and biochemical properties (pH, temperature and salt resistance) and sequence analysis of 16S rRNA gene. Antibacterial activity of representative strains of lactic acid bacteria were detected. [Results] We identified 23 strains as Lactobacillus fuchuensis (48.94%), 12 strains Lactobacillus curvatus (25.53%), 3 strains Leuconostoc fallax (6.38%), 2 strains Lactobacillus sakei (4.26%), 2 strains Weissella ceti (4.26%); 2 strains Lactococcus cremoris (4.26%), 1 strains Leuconostoc lactis (2.13%), 1 strains Weissella minor (2.13%), and 1 strains Enterococcus devriesei (2.13%). Groups A, B and C could grow between 5 and 50 °C. Groups B and C could grow between pH 3.0 and 10.0. Almost all of the lactic acid bacteria were resistant to 6.5% Nacl concentration. The supernatant could inhibit the growth of indicator strains. By excluding hydrogen peroxide and organic acid, we found that it still has antimicrobial activity. The inhibitive activity decreased after treatment with pepsin, which indicated that this inhibitory material had the features of protein. It could be classified as bacteriocin. [Conclusion] G. przewalskii intestine adhesion diversity of lactic acid bacteria, which will provide quality resources for probiotic lactic acid bacteria and data reference.