一株高产细菌素乳酸菌的分离与鉴定

Isolation and Identification of a High Bacteriocin-producing Lactic Acid Bacterium

为了满足细菌素的市场需求,降低生产成本,筛选高产细菌素菌株并应用于食品生产成为当前研究的重点。本研究从东北自然酸菜发酵液中分离筛选出一株高产细菌素的乳酸菌11MZ-5-2,发酵48 h时,细菌素含量达到(344.47±5.50)IU/m L。采用生理生化及分子生物学方法鉴定该菌株,并构建系统发育树。结果表明:菌株11MZ-5-2为革兰氏阳性细菌,杆状,无芽胞,最适生长温度为30~37℃,耐盐范围为0%~10%,最适pH 5.5~6.5,主要脂肪酸组分为C16:0、C18:0和C18:1。16S r DNA部分序列长度为1446 bp,与植物乳杆菌(Lactobacillus plantarum)IDCC 3501相似性最大,达99%,将该菌株命名为L.plantarum 11MZ-5-2。菌株L.plantarum 11MZ-5-2可作为发酵剂或将细菌素产物应用于食品中,可以有效地防止杂菌污染,延长食品保质期。

In order to meet the market demand of bacteriocin and reduce the production cost, screening a high bacteriocin-producing bacterium and applying it to food production has become the focus of current research. In this study, a lactic acid bacterium 11MZ-5-2 with high bacteriocin-producing ability was isolated from liquid sample of pickle Chinese cabbage. The bacteriocin titer of strain 11MZ-5-2 was （344.47＋5.50） IU/mL after 48 h fermentation. Strain 11MZ-5-2 was identified according to physiological and biochemical methods. Meanwhile, the phylogenetic tree was constructed based on its partial 16S rDNA sequence. The results showed that strain 11MZ-5-2 was a kind of rod gram-positive bacterium with no spores, the optimum temperature range was 30-37~C and the salt-tolerance range was 0%-10%, and the optimum pH range was 5.5-6.5. The main aliphatic acid components of strain 11MZ-5-2 were C16：0, C18：0 and C18：1. The partial sequence of the 16S rDNA of strain llMZ-5-2 was 1446 bp which was 99% similar with Lactobaeillusplantarum IDCC 3501. Strain 11MZ-5-2 was identified as L. plantarum. L. plantarum 11MZ-5-2 could be applied as a starter culture in food fermentation. Furthermore, the bacteriocins produced by L. plantarum l lMZ-5-2 could be used as preservatives in food to prevent bacterial pollution and prolong the shelf-life.