风干香肠中乳酸菌的分离鉴定及益生特性研究

Probiotic characteristics of lactic acid bacteria from dry fermented sausages

由风干香肠中分离纯化得到的3株乳酸菌ORC2、QM7和QM8,均能产乳酸、革兰氏染色阳性、接触酶阴性。经系统发育分析,结合菌落形态、细胞形态、生化反应试验,确定菌株ORC2和QM7为肠膜明串珠菌,QM8为柠檬明串珠菌。乳酸菌ORC2、QM7和QM8均能降低培养基中的胆固醇,且对·OH、DPPH·和O-2·有一定的清除能力,其清除率都与细胞浓度呈正相关。在细胞浓度为5×108CFU/mL时,菌株ORC2对·OH的清除率最高,为65.36%;菌株QM8对DPPH·的清除率最高,为61.21%;而对O-2·的清除率最高的菌株为QM7,达到75.70%。菌株QM7在培养96 h能清除最多的胆固醇,清除率为51.2%。

Three strains of lactic acid bacteria, strain ORC2, QM7 and QM8, were obtained from dry fermented sausages. All 3 strains were gram-positive, lactic acid-producing, and catalase-negative. Based on morphological, physiological, biochemistry test and 16S rDNA sequencing analysis, ORC2 and QM7 were identified as Leuconostoc mesenteroides, and strain QM8 as Leuconostoc citreum. These isolates showed the ability to remove cholesterol, and to inhibit ·OH, DPPH· , and O2-·. The three radicals scavenging ratios for three strains were positively correlated with bacterial density. At a concentration of 5×10^8 CFU/mL, ORC2 showed the highest radical-scavenging ratios （removal rate, 65.36% ） on·OH, QM8 exhibited the strongest DPPH · radical scavenging ability （removal rate, 61.21% ）, and QM7 scavenged most O2-· radical （removal rate, 75.70% ）. For 96 h, strain QM7 could remove 51.2% cholesterol in media, which was far more than either LAB alone.