发酵乳杆菌(Lactobacillus fermentum)YB5生理特征的研究

Studies on the Physiological Characteristics of Lactobacillus Fermentum YB5

为了开发优良的益生菌菌株,对分离自酸奶的发酵乳杆菌(Lactobacillus fermentum)YB5的生理特性进行了系统研究。耐渗透压试验结果表明,发酵乳杆菌YB5具有一定的耐渗透压能力,其在4%NaCl溶液中生长正常,而在6%NaCl溶液中生长受到抑制;耐酸性试验结果表明发酵乳杆菌YB5具有较强的耐酸性,能够在pH值2.5的培养基中生长;双层平板法抑菌试验结果表明,发酵乳杆菌YB5能产生抑菌物质,该物质对革兰氏阳性菌有明显的抑制作用;YB5抑菌活性具有较强的热稳定性,经40℃或60℃热处理后,其抑菌活性增强;YB5抑菌活性耐酸性,在弱酸和中性环境中其活性降低或丧失。淀粉酶活力检测结果表明,发酵乳杆菌YB5在生长过程中能产生淀粉酶。YB5的这些特性预示着其在食品加工中具有很好的应用潜力。

In order to investigate the probiotie function, the physiological characteristics of heterofermentative Lactobacillus fermentum YB5 were studied systematically. The results showed that L. fermentum YB5 had a stronger osmotictolerant ability, it grew well on MRS agar supplemented with 6% NaCI, while Lactic acid bacteria toleranted normally 4% NaCl. L. fermenturn YB5 have an acidic resistance which could survive at pH 2.5. The bacteriocin, produced by L. fermentum YB5, is active against a widely range of Gram positive bacteria, as well as some pathogens such as E.coli, Staphylococcus aureus. Interestingly, this antimicrobial substance could promote the growth of Aspergillus niger under low concentration. It was heat stable even at 40 ℃ or 60 ℃ temperature and highest activity in the lower pH range （2-3）. Moreover, L. fermentum YB5 had the capability of amylase activity when grew in the medium containing starch. As a result, L. fermentum YB5 is a good strain in the potential application as probiotics.