在大自然中包括動植物、昆蟲與細菌等，均可以產生天然抗菌月生肽，而細菌所產生的抑菌蛋白質稱為細菌素 (bacteriocin)。對動物無毒性、易被人體消化道中的蛋白酶降解、不會在體內蓄積引起不良反應等特性，被認為是一種具有廣闊應用前景的天然食品防腐劑，非常適用於食品工業。其中乳鏈球菌素 (Nisin)已被廣泛應用。
本研究的主要目的是篩選和鑑定具有較廣抑菌範圍之細菌素生產菌株並探討細菌素之最適純化條件。在159株乳酸菌菌株中，排除有機酸、過氧化氫等干擾因素後，篩選出編號NO.13菌株，經菌種鑑定後確認為 Lactobacillus plantarum，以此菌株作為我們的研究對象。種菌培養時，在24小時為菌體與細菌素的含量為最大量。使用菌體吸附釋放法在時間上可以比傳統蛋白質純化法快。蛋白質電泳分析得到主要條帶，與抑菌位置相同，分子量低於14 kDa。Lipase對細菌素有較強之抑制，抑菌活性僅餘12.8%。Typsin對細菌素有較弱之抑制，抑菌活性仍有62.3%。Staphylococcus aureus對細菌素作用最好，抑菌活性達100％。Shigella flexneri對細菌素作用較差，抑菌活性僅14.1%。細菌素隨著pH 的增加，抑菌活性逐漸消失。細菌素隨著加熱溫度至70℃以後，抑菌活性逐漸下降。 Among the variety of antimicrobial substance produced by lactic acid bacteria (LAB), bacteriocins are one of the most promising natural food preservatives. Because of the inhibitory activity of bacteriocins against a variety of food spoilage-causing and/or competing organisms, bacteriocin producing LAB have been widely used in dairy, meat, and vegetable fermentations.
The main purpose of this research is screening, identification and purification conditions of high productivity bacteriocin- producing Lactic Acid Bacteria Strain for bacteriocin. Lactobacillus plantarum No.13, which is a bacteriocin producer isolated from kimchi. Kinetic study of L. plantarum No.13 showed that the production of antibacterial activity started at the fourth day after inoculation, then gradually increase to reach a maxium at the 24 hours. Bacteriocin can be recovered by cells adsorption- desorption. The specific activity of the purified bacteriocin was 256.9 AU/mg, with 1.5% recovery. Bacteriocin has been described as the Class II produced by a strain of L. plantarum No.13, with a molecular mass lower than ca. 14 kDa. The bacteriocin had a high substrate specificity for lipase and was inhibited by trypsin. The bacteriocin were active against Staphylococcus aureus. Optimal pH and temperature of the purified bacteriocin from L. plantarum No.13 was stable in 2.0 and below 70℃, respectively.
