Lactobacillus spp. (LAB) 屬是被廣泛研究的益生菌。在釵h實驗及臨床研究證實對人類的健康是有幫助的。乳酸菌的代謝物質已經發現對不同細菌種類具有潛在的抑制活性，包含Streptococcus spp.。在排除酸與過氧化氫的干擾後，乳酸菌分離株編號 B0105 生產的細菌素（bacteriocin），以平板擴散法分析抗菌活性，並與工業上常用來生產細菌素（nisin）的菌株進行比較，乳酸菌 B0105 生命的細菌素具有抑制 S. mutans 的能力，經由初步生理特性判定，再以 16S rDNA sequences 作序列鑑定後，確定為Lactobacillus plantarum。此外，我們發現以自製培養基 DMB（20％ dextrin）生產的細菌素（bacteriocin）與MRS broth 生產之細菌素，具有相同的抑菌活性。使用吸附釋放法純化細菌素並經由 SDS-PAGE 分析後，分子量介於3.5 kDa ～ 17.0 kDa 之間。 Lactobacillus spp. (LAB) are widely studied probiotic bacterium. Its beneficial effects on human health are documented in many experimental and clinical studies. LAB have been shown to produce a substance with potential inhibitory activity against different bacterial species including cariogenic Streptococcus spp.. LAB isolated strain (B0105) producing bacteriocin against Streptococcus mutans under the condition of elimination of acid and hydrogen peroxide effect was identified and name as Lactobacillus plantarum based on the biochemical properties and 16S rDNA sequences. Antibacterial activity was examined by the diffusion plate method as compared with a reference strain used as industrial producing bacteriocin（nisin）. The bacteriocin from LAB B0105 had the ability to inhibit S. mutans, suggesting that it could be a promising alternative biopreservative agent for S. mutans infections. Antimicrobial peptide, bacteriocin, produced by B0105 incubated in DMB (20％ dextrin) medium produced by self-prepared had the same antimicrobial activity with bacteriocin produced by MRS medium. On the basis of absorption method, the partially purified bacteriocin had a molecular weight of approximately 17.0 to 3.5 kDa, analyzed by SDS-PAGE.