摘要

从能够产生细菌素的传统发酵食品和生物提取物中分离出32株乳酸菌。发现从生物提取物中分离的一种菌株LAB7能够抑制大肠杆菌TISTR780和金黄色葡萄球菌TISTR1466。它的特性是在121℃下15分钟的耐热性和在pH2-9的宽范围内稳定。包封实验使用截留在含有106CFU /珠的藻酸钙珠中的LAB7菌株进行。将包封的细胞以10％接种量接种到MRS肉汤中，并在30℃下在分批条件下生长24小时。使用和不使用搅动的游离细胞用于比较封装对细菌素生产的影响。还研究了底物消耗量，生物量和乳酸产量。结果显示包封的细胞产生2.92g / l / h的最高乳酸。培养10h后，抗大肠杆菌TISTR780的细菌素活性为3200AU / ml，培养8h后抗金黄色葡萄球菌TISTR1466的活性为800AU / ml。然而，没有搅动条件的游离细胞分别对抗大肠杆菌TISTR780和金黄色葡萄球菌TISTR1466仅产生1600AU / ml和400AU / ml的细菌素活性。结果表明，LAB7不仅产生针对革兰氏阳性菌和革兰氏阴性菌的细菌素，而且在藻酸钙珠中封装细胞时也强烈表现出高细菌素活性。

Thirty two strains of lactic acid bacteria were isolated form traditional fermented foods and bio-extract for their abilities to produce bacteriocins. One strain, LAB7, which isolated from bio-extract were found to be able to inhibit Escherichia coli TISTR 780 and Staphylococcus aureus TISTR 1466. Its properties were heat tolerance at 121 °C for 15 min and stable at wide pH range of 2-9. The encapsulation experiments were conducted with LAB7 strain entrapped in calcium alginate beads which contained 106 CFU/bead. The encapsulated cells were inoculated into MRS broth at 10% inoculums and grew in batch condition at 30°C for 24 h. Free cells with and without agitation were used to compare the effect of encapsulation on the bacteriocin production. Substrate consumption, biomass and lactic acid production were also investigated. The results showed that the encapsulated cells produced the highest lactic acid at 2.92 g/l/h. The bacteriocin activity against E. coli TISTR 780 was 3200 AU/ml after cultured for 10 h and the activity against S. aureus TISTR 1466 was 800 AU/ml after cultured for 8 h. Whereas, free cells without agitation condition gave bacteriocin activity against E. coli TISTR 780 and S. aureus TISTR 1466 only 1600 AU/ml and 400 AU/ml, respectively. It was indicated that LAB7 not only produced bacteriocin against both Gram positive and Gram negative bacteria, but also strongly present high bacteriocin activity when encapsulated cell in calcium alginate beads.

https://www.tci-thaijo.org/index.php/APST/article/view/84071