摘要

本研究集中于使用M-17肉汤从乳酸乳球菌MTCC440产生，纯化细菌素特别是乳链菌肽并评估其对各种病原体的拮抗活性。细菌素的最佳生产发生在pH 5，温度30℃，1％盐度，葡萄糖作为碳源和蛋白胨作为氮源。使用来自粗提物的硫酸铵沉淀细菌素并使用透析进行部分纯化。通过SDS PAGE进一步分析纯化的细菌素，发现乳链菌肽的分子量为3.4kDa。抗菌活性显示出对金黄色葡萄球菌（20mm），藤黄微球菌（11mm）和马戏芽孢杆菌（11mm）的最大抑制区域。这揭示了细菌素尤其是乳酸乳球菌MTCC440产生的乳链菌肽作为保护培养物用于提高发酵食品的微生物安全性和减少导致人类疾病的食物污染的潜在应用。因此，本研究证实了使用菌株乳酸乳球菌MTCC 440作为生物防腐剂和益生菌的可能性。

The present study was concentrated on the production, purification of bacteriocin particularly Nisin from Lactococcus lactis MTCC 440 using M-17 broth and its antagonistic activity against various pathogens were assessed. Optimal production of bacteriocin occurred at pH 5, temperature of 30ºC, 1% salinity, glucose as carbon source and peptone as nitrogen source. Bacteriocin was precipitated using ammonium sulphate from the crude extract and partially purified using dialysis. The purified bacteriocin was further analysed by SDS PAGE and the molecular weight of Nisin was found to be 3.4 kDa. Antibacterial activity showed maximal zone of inhibition against Staphylococcus aureus (20mm), Micrococcus luteus (11mm) and Bacillus circus (11mm). This reveals that the potential application of bacteriocin particularly nisin produced by Lactococcus lactis MTCC 440 as a protective culture for the improvement of the microbial safety of fermented foods and reduction in food contamination which causes illness to human beings. The present study thus confirmed the possibility of using the strain Lactococcus lactis MTCC 440 as a bio-preservative and a probiotic.

http://ijamicro.com/19-2-2016/D-Selvakumar.pdf