内蒙古奶豆腐中产胞外多糖乳酸菌的分离筛选

Isolation and Screening of Exopolysaccharides-producing Lactic Acid Bacteria from Inner Mongolia Dairy Tofu

从内蒙古牧民自制的传统发酵乳制品"奶豆腐"中分离得到4株乳酸杆菌。经表型、生理生化和API鉴定,这4株菌都是植物乳杆菌,分别为植物乳杆菌C2、C8、C15和C21。采用负染法观察菌株荚膜多糖产生情况,菌株C8、C15和C21都产生荚膜多糖,在普通光学显微镜下荚膜清晰可见。对4株植物乳杆菌48h内的生长和产胞外多糖情况进行分析发现,本实验中的4株植物乳杆菌在发酵48h内的胞外多糖产量逐渐增加,其中植物乳杆菌C21的产量最高。

Four Lactobacilli stains were isolated and screened from traditional fermented dairy products dairy tofu popular in Inner Mongolia.According to phenotypic,physiological-biochemical and API tests,the strains were all identified as Lactobacillus plantarum and named C2,C8,C15,and C21,respectively.The negative staining method was used to observe their capsules,and the results indicated that except strain C2,all the others produced capsular polysaccharides and the capsules could be seen by using optical microscopy.The 48 h growth and exopolysaccharide-producing ability of the four strains were analyzed.It was found that all these strains exhibited a gradually increasing exopolysaccharides production during 48 h culture,and strain C21 produced the highest amount of exopolysaccharides.